INTELLIGENCE MEASUREMENT A Psychological and Statistical Study Based upon the Block-design Tests. THE MACMILLAN COMPANY NEW YORK • BOSTON • CHICAGO • DALLAS ATLANTA • SAN FRANCISCO MACMILLAN & CO., Limited LONDON • BOMBAY • CALCUTTA MELBOURNE THE MACMILLAN CO. OF CANADA. Ltd. TORONTO THE BLOCK-DESIGN TEST Courtesy Psychological Review Co. INTELLIGENCE MEASUREMENT A Psychological and Statistical Study Based upon the Block-design Tests BY S. C. KOHS, Ph.D. PSYCHOLOGIST, COURT OF DOMES'!IC RELATIONS, PORTLAND, OREGON; ASSISTANT PROFESSOR OF PSYCHOLOGY, REED COLLEGE, AND PROFESSOR OF PSYCHOLOGY, PORTLAND CENTER, UNIVERSITY OF OREGON 1Rew Jflorfe THE MACMILLAN COMPANY 1923 All rights restrved PRINTED IN THE UNITED STATES OP AMERICA Copyright, 1928, By THE MACMILLAN COMPANY Set up and electrotyped. Published April, 1923. Press of J. J. Little & Ives Company New York, U. S. A. TO HENRY HERBERT GODDARD WHOSE PIONEER INTEREST IN INTELLIGENCE MEASUREMENT GREATLY ACCELERATED THE RAPID PROGRESS OF THIS PROMIS- ING BRANCH OF SCIENCE, A MAN OF BROAD SYMPATHY, WITH KEEN UNDERSTANDING OF THE PROBLEMS CONFRONTING THOSE OF DEFICIENT MENTALITY, ONE TO WHOM THE WRITER OWES HIS INITIAL DIRECTION IN THIS BROADLY HUMANITARIAN FIELD, THIS BOOK IS GRATEFULLY DEDICATED PREFACE New mental test methods of demonstrated validity are always welcome, and this is especially true just now of those which are relatively independent of the language factor. Other things being equal, any psychologist prefers to rate the intelligence of his subjects by what they can do rather than by what they say. Very often the “other things” are not equal, and the test which uses language possesses certain advantages that are not to be lightly set aside. The carefully worked out per- formance test, however, has a wide field of usefulness, as all who have engaged in clinical work will readily admit. The need for such tests has never been adequately met, largely because really valid ones are much more difficult to devise than is the case with tests which utilize lan- guage. In the upper ranges of intelligence, especially, most performance tests have but little differentiating value, simply because they do not draw heavily enough upon the higher mental processes. In the Block-design test, Dr. Kohs has largely overcome this difficulty, and has given us an intelligence scale which is certain to prove extremely useful. His success, we believe, is the direct result of his thoroughgoing appreciation of the real nature of the mental processes involved in what we call intelligence. Lewis M. Terman. VII INTRODUCTION “What is the nature of mind?” This question, pro- pounded when man first became conscious of himself, still remains but inadequately answered. Nevertheless, some evident progress has been made. The light of scientific progress is gradually penetrating the various nooks and recesses of our mental life, and the machinery of thought, although dimly revealed, is becoming more apparent in its operation. This monograph is but a mere fragment, explaining little if anything regarding the dynamics of mental process, yet it hopes to place a variety of perplexing problems in a new perspective. We shall have occasion, for example, to examine some current definitions of intelligence, and we shall indicate wherein our research into the value and significance of completion and combination tests forces us to a recon- sideration of the criteria of intelligence and to a restate- ment and a redefining of some fundamental principles. By mentioning in this connection the great importance of the “analytic-synthetic” tendency characteristic of all mental behavior, from the simplest sensory, ideational, and affective states to the most complex, wre are really anticipating a later discussion of these matters. Suffice it to say that psychology has not yet interpreted our mental constructs in terms of a synthetic principle, although our philosophers have already blazed a some- what ambiguous trail. IX X INTRODUCTION It has often been urged that the position of neutrality is one full of danger for its claimant. Although this may be adjudged a “ behaviorist ” study, nevertheless full weight has been given to those contributions of “ struc- turalists’’ and “functionalists” which have thrown light upon our particular problem. The psychological family is at discord unless each member is willing, not alone to see the others’ point of view with tolerance, but to accept at its real value any scientific contribution no matter what the standpoint of the experimenter. This is no apology for the present study — the remarks are intended merely to emphasize our community of problems, and the possibility that each school of method may throw some light on all of them. We are all confronted with the question, “What is the nature of mind?” Knowing the futility of any complete reply, we have accustomed ourselves either to ignore the question or to maneuver a Freudian “escape from reality” by losing ourselves in metaphysical speculation. If this piece of work yields but a little toward an additional understanding of this baffling problem our efforts will, indeed, be wrell rewarded. S. C. Kohs. Portland, Oregon, August 30, 1921 CONTENTS PAGE Dedication to H. H. Goddard v Preface by Dr. L. M. Terman vii Introduction ix PART A: THE PSYCHOLOGY OF ANALYSIS AND SYNTHESIS 1. Philosophical Orientation 3 2. Psychological Orientation 7 3. Neurological Orientation 27 4. Summary 32 PART B: THE BLOCK-DESIGN TEST CHAPTER I. Statistics Regarding the Subjects Who Were Given the Block-design Tests .... 39 II. The Test Material 1. The Material 64 (a) The Blocks (b) The Designs (c) The Score Card and the Method of Scoring (d) The Norms 2. The Directions for Applying the Tests ... 74 III. Standardization Technique 1. The Year-Scale Method 78 2. The Percentile Method 80 3. The Point-scale Method 98 4. The P. E. or Linear Projection Method ... 99 IV. The Standardization of the Block-design Tests 1. Introduction .102 XI XII CONTENTS CHAPTER PAGE 2. Age Standardization 104 (a) Mental Age Norms (b) Sex Differences (Mental Age Norms) (c) Chronological Age Norms (d) Sex Differences (Chronological Age Norms) (e) Graphic Presentation of Norms (/) Final Year Scale 3. P. E. Standardization 130 (a) Method (b) Time and Move Norms (c) Result: The P. E. Scale 4. Final Revision 161 (a) Eliminations (b) Sex Differences (c) Final Norms V. The Results 1. Do the Block Designs Measure Intelligence ? . 168 2. Validity 172 3. Diagnostic Value of the Tests 233 4. Serviceability 235 VI. Supplemental Observations 1. Average Mental Age of Adults 237 2. Increasing Divergence vs. Parallel Progress of Mental Development 262 3. A Performance Intelligence Scale 271 PART C: APPENDICES I. Grouped Distributions op Ability 273 II. New Correlation Method 289 III. Elaboration op Sheppard’s Table 296 IV. Typical Block-design Records 300 Index 305 PART A THE PSYCHOLOGY OF ANALYSIS AND SYNTHESIS THE PSYCHOLOGY OF ANALYSIS AND SYNTHESIS The Place of Synthetic and Analytic Functioning in Psychic Activity I. PHILOSOPHICAL ORIENTATION The psychology of combinative or completive ability leads us back through the early history of psychology to the time when philosophers psychologized and psycholo- gists philosophized. The limited confines of our study compel brevity, and we need go back no farther than the “associationist” school. Hobbes, a staunch materialist, the contemporary of Bacon, Descartes, and Galileo, may rightly be called the father of “associational” psychology. Hobbes “mate- rialized” mental activity. Psychic behavior was inter- preted as mental physics or chemistry. All knowledge arises through sensations, which, combined in certain definite forms, yield the various complex mental pro- cesses. Conscious states are due to the refined move- ments of mental atoms controlled by the laws of asso- ciation, the foundation-stones of mental functioning. Words are nothing but mere symbols, markers. It is their combination, their addition, their subtraction, which yields thought. 3 4 INTELLIGENCE MEASUREMENT The legitimate successor of Bacon and Hobbes was John Locke. From a psychological point of view, it may be of interest to note that his “Essay on the Human Understanding” grew out of his attempt to answer the question: “What is the nature of sensations?” He began by asserting that there are no “innate ideas,” in opposition to the position of Descartes and to the later views of Spinoza and Leibniz. At the beginning, mind is a “white piece of paper,” upon which impres- sions are marked. Ultimately “nothing is in the intel- lect that has not been first in the sense.” But the mind is not a passive receptacle. It can manipulate and com- bine ideas. These ideas are derivates of “simple ideas” out of which the more complex have been compounded. This compounding is explainable in terms of the laws of association. Hume, an outstanding sensationalist, maintained that no ideas existed which were not derived from impressions, a position to which many of our present-day psycholo- gists would claim adherence. Impressions are of two kinds: sensational (outer) and affective (inner). And ideas are copies or echoes of these simple elemental states. Much of his psychology is devoted to a discus- sion of the compounding or the combination of ideas, and this to such a degree, that his whole psychology be- comes warped in its exaggeration of the actual part played by associational processes. The differences be- tween conception, memory, imagination, judgment, and so on, are largely differences in the forms by means of which ideas combine. All mental behavior is just asso- ciation between ideas. Ideas possess “forces” or “de- PHILOSOPHICAL ORIENTATION 5 terminations ” which tend to bring and keep them together. The individual then is helpless, since these “forces” follow fixed, mechanical laws. Leaving the “associationists,” we find Kant, among philosophers, giving perhaps the clearest exposition of the hierarchies of mental functioning, progressing through hierarchies of mental “synthesis.” Kant, perhaps, has dealt more extensively with “men- tal synthesis” than any other single philosopher. His task as a philosopher was largely epistemological. His metaphysical structure, although promised, never ap- peared complete. It remained for others, Fichte, Hegel, Schelling, Herbart, and Schopenhauer, to take the step beyond. Kant was interested in the processes which give us knowledge. He postulated a threefold world: one, of subjective states (inner consciousness), another of phenomena (knowledge), and another of absolute reality (Ding-an-Sich). The first realm each individual can alone experience, the last no one can experience, the second, however, is common property and can be intel- ligently discussed by all of us. To Kant, subjective states are synthetic products, different in every one of us. And in each of his three books which compose his “Critique of Pure Reason” he discusses the different levels of synthetic activity: (a) in perception, (b) in understanding, (c) in reason. In his search for the pro- cesses which yield knowledge, he concluded that the im- portant factor was the synthetic power of mind. In this sense mental functioning is dynamic. If one can imagine an individual who lacks this synthetic power, the ticking of a clock would be nothing more than tock, tock, tock. 6 INTELLIGENCE MEASUREMENT To those, however, who do possess it, the clock’s ticking is perceived as one, two, three, etc. The experience is cumulative, each item including its prede- cessors. Kant very clearly differentiated between mental end- results and synthesis — one a product, the other a process. Synthesis is not subject to volitional vicissi- tudes, but is a heritage common to all. It is for that reason that we can agree upon such matters as physical laws, time-estimates, standards, and so on. Racial differences in thought and knowledge are differences largely of synthetic potentiality. Groups, therefore, may misunderstand each other because of this basic difference, since differences in synthetic power will lead to differences in thought and behavior. “The world is my representation,” says Kant. Knowledge is a com- bination of sensations or ideas, “a unification of the manifold.” And the expression of knowledge is through the judgment, which may be analytic or synthetic. Kant discusses quite extensively the distinction between the two types, but there is no need of our following his argument farther. Few, if any, of the terms we use to express our thoughts come to us as an immutable, unchanged, and unchange- able heritage. Although we continue using the same terms, these take on changing meanings with the changes in our notions regarding the character of the individual and of the cosmos. Therefore, although we shall fre- quently utilize the terms “analysis” and “synthesis” throughout this monograph, thev are not to be construed other than as here defined. PSYCHOLOGICAL ORIENTATION 7 1. By “synthesis” we mean, on the one hand, the intensity of that fundamental force or condition innate in nervous protoplasm which binds neurons into complex systems, and, on the other hand, the capacity of a living organism to construct out of mental elements and frag- mentary experiences, concepts and notions of a higher order. The fuller elaboration of these statements is left for the succeeding paragraphs. 2. By “analysis” we mean the capacity for observing or discovering parts or differences in objects or qualities which for themselves seem unitary. 3. Although one can only speculate on these matters, it seems reasonable that analysis and synthesis are but the head and tail of a single function-tendency. This “analytic-synthetic” activity may be regarded a funda- mental property characteristic of all irritable tissue, and more markedly so of nervous tissue. All forms and degrees of this function-tendency seem possible, from the simplest to the most complex. 2. PSYCHOLOGICAL ORIENTATION If one thumb through the average psychology for a description and an analysis of the mental process of synthesization, integration, fusion, discrimination, differ- entiation, comparison, combination, blending, assimila- tion, and analysis, one’s search will prove rather barren. Yet, as we shall have occasion to observe in greater detail later, these processes appear most fundamental for normal mental development. The elements or primary structures of consciousness escape our observation. What we experience, what we 8 INTELLIGENCE MEASUREMENT observe when we introspect, are fused or synthesized products of these elements. It has been said with justice that “Whoever would understand the facts of experience must know how they are built up out of the combination of elements.”1 Take mental functioning anywhere along the line, from the simplest type of perception to the most complex higher thought process, and at every point evi- dences of synthetic activity are observable or may safely be postulated. Percepts are synthesized sensations, ideas are synthesized percepts, images are recalled traces of these synthesized products, coordinations are orderly combinations of reflexes, judgments are orderly combina- tions of ideas, reasoning results from an orderly combina- tion of judgments — emotion, will, learning, habit, all are combinations of some elementary form of mental process, these conscious states becoming more complex with the increase in complexity of the integrative pattern. “Consciousness is not a shower of shot,”2 a mass of disconnected elementary states, but at every stage it consists of a fusion of elementary processes into those more complex, and these finally into a functional unity. Psychology may well be defined as the science devoted to a study of mental elements, sensations, images, and affections, and the manner, condition, laws, concomitants, and effects of their combination at different develop- mental levels, phylogenetic and ontogenetic, normal and abnormal. This is a task alike for the structuralist, 1 Judd, 13; 28. All references are to the bibliography at the end of Part A. * Royce, 24; 108. PSYCHOLOGICAL ORIENTATION 9 the behaviorist, the functionalist. It cannot be pre- empted by one, nor completely dealt with except by all. At the bottom of this conception of mental elaboration is an implication which approaches the speculative. We cannot, however, on that account escape the force of its bearing on a reasonable explanation of observed con- ditions. In chemistry and physics the phenomenon of crystallization is thoroughly familiar. Given a fluid containing the proper ingredients, under certain condi- tions crystallization will take place. The canons of science justify our inquiry into the “how” but not the “why.” Nevertheless, the postulation of a force or of forces, closely bound up perhaps with the atoms or the molecules, acting concertedly under fixed law and resulting in a new product, is a postulation which few will attempt to deny scientific scrutiny. So, too, in considering the mechanics of mental elaboration, to postulate a fundamental force or forces making for higher degrees of mental organization and for varieties of higher thought forms need not be considered irrelevant. The fundamental “ability” to “synthesize” or “combine” is not one which we may “will” to possess or not. We “synthesize” entirely independent of our personal choice in the matter. Just as we can exercise little if any control on the hyperfunction or hypofunction of some of the other organs of the body — for example, the kidney, the thyroid, the intestines — so also is our interference with brain function nominal. It seems evident that if one is born with good mental endowment his brain will “synthesize” to a degree and in a manner impossible to one whose native mental endowment is poor. Of course, 10 INTELLIGENCE MEASUREMENT it is left, more or less, to individual initiative to exercise this inherited endowment efficiently. And yet, tests of “completion” or “combination” may measure this “synthesizing ability” in a very rough fashion, quite independent of schooling or other formalized training. Differences in level of mental ability may some day be explained, among other things, on the basis of differences in fundamental synthesizing ability, or the capacity of the nervous system to fuse elementary states of conscious- ness into higher thought forms. And perhaps the dif- ferences between a superior intelligence and a deficient intelligence may be found largely due to differences in this original basic synthesizing capacity. Hobhouse has stated: “ Where there is mind there is order and system, corre- lation and proportion, a harmonising of forces, an inter- connection of parts. The organism which is gifted with intelligence shows it by arranging its actions on a certain plan. It adapts means to ends, which is one sort of correlation, and in so doing it perhaps brings a past experience to bear, interpreting a perception, for exam- ple, by memory; and this is another sort of correlation.”1 Wherever we find traces of mental functioning there we inevitably observe the organization and correlation of mental elements into hierarchies. And this organization of mind on any functional level is evidenced by a parallel organization of behavior. In general, it might be stated that organized action is a product of intelligence, un- organized action the result of the absence or non-use of intelligence. And throughout the realm of mental func- 1 Hobhouse, io; 6. PSYCHOLOGICAL ORIENTATION 11 tioning we note rather clearly the tendency for the fusion of elemental, conscious states into more complex forms, forms which serve more readily for individual adapta- tion to environmental demands. “Our assimilations have not merely to do with the processes of perception and memory: they appear on the highest level of the intellectual life. All our thinking involves assimilation. When a novel object puzzles us, or when a problem baffles us, that is because we have not yet learned to assimilate the new experience to our former fashions of conduct. But when our puzzle is thought- fully satisfied, this occurs because we have learned to assimilate the new facts to the old principles, i.e., to adjust our former methods of conduct, with a minimum of change, to the new situation. When the problem is solved, that is because what baffled us about a question which was asked, but to which we could not respond, disappears, because we have assimilated the matter at issue by remembering from our former experience an answer that serves the purpose. To be sure, such assimi- lation may be accompanied with alterations of habits that will need to be considered later under the head of Mental Initiative. But every thoughtful process is, in at least one respect, a process of assimilation1 In what manner is this concept of a synthesizing, or an assimilative, or combinative, or integrative principle different from our earlier and now discarded view that “associations of ideas” serve as a complete explanation of the varieties of mental experience? Our present hy- pothesis is rather one which assumes nervous tissue to possess the property or tendency of becoming integrated into higher units of complexity, as well as the tendency 1 Royce, 24; 245. 12 INTELLIGENCE MEASUREMENT for organizing environmental stimuli which appeal to various sense modalities into a consistent, understand- able, and assimilable unity. The “association of ideas” is perhaps the most obvious superficial result of this synthetic-analytic tendency. It should be kept in mind, however, that “associations” evidence the result and not the process of this fundamental integrative force. The process is inherent in nervous tissue, and the result is present in consciousness as “associations between ideas.” Titchener admirably summarizes the situation in seven words: “The brain associates, and meanings are associated.” 1 In general, it may be said that “the entire process of elaborating . . . objects of perception by the senses, presupposes for its explanation a constant activity of the mind ... in combining the sensations into ever more complex forms. This combining activity is best called ‘syntheticor ‘constructive”2 Nevertheless, there is an analyzing activity of mind which apparently is as important as the synthesizing. And perhaps analysis and synthesis are merely two aspects of nerve cell mechanism. Although antonyms, and expressing oppo- site tendencies, analysis and synthesis show evidences of each reenforcing and aiding the other. Our aim is not to make hair-splitting distinctions be- tween the processes of synthesis, assimilation, blending, combination, completion, induction, fusion, on the one hand, and analysis, comparison, deduction, differentia- tion, discrimination, on the other. It is sufficient to 1 Titchener, 29; 149. 2 Ladd and Woodworth, 14; 384. PSYCHOLOGICAL ORIENTATION 13 state that the process or processes to which these terms refer are fundamental and may represent innate, dynamic potentialities characteristic of all nervous tissue. Many have attempted to differentiate the analytic activity from the synthetic. Our immediate purpose, however, will not necessitate any other assumption than that brain substance fundamentally manifests this activity — analysis and synthesis. Whether there are different “types”1 is irrelevant to the present discussion. It perhaps is true, however, that at different age levels the character of the analyses and syntheses is different, the processes themselves changing as one passes through infancy to childhood, to adolescence, to adulthood, and finally through senescence. Thorndike remarks that “the intellectual life of man seems to consist as much in discriminating, abstracting, taking apart, as in associating or connecting.”2 Al- though “fusion of some kind is always present in expe- rience,”3 nevertheless, the other aspect cannot be over- looked: “Closely allied to the fact of focalness of thinking is the fact of analysis, the fact of breaking up a total fact into its elements, parts, or aspects. It is only as a result of such a process of breaking up total facts into their qualities that the elements of color, size, shape, weight, pressure, and the like are felt, in place of a ‘big, blooming, buzzing confusion.’ It is only as a result of such a process that many feelings of meanings and of intellectual relationships arise at all.”4 1 Meumann, 17. 2 Thorndike, 27; 35 3 Judd (ist ed.), 13; 137* 4 Thorndike, 28; 105. 14 INTELLIGENCE MEASUREMENT James clearly and with due emphasis maintains: “After discrimination, association!”1 In speaking of these two processes, he says: “It is obvious that the advance of our knowledge must consist of both operations; for objects at first appearing as wholes are analyzed into parts, and objects appearing separately are brought together and appear as new compound wholes to the mind. Analysis and synthesis are thus the incessantly alternating mental activities, a stroke of the one preparing the way for a stroke of the other, much as, in walking, a man’s two legs are alternately brought into use, both being indis- pensable for any orderly advance.” 2 Hobhouse expresses a somewhat similar idea: “Analysis rests on comparison, which is an act of synthesis, since it brings different experiences into rela- tion; and gains in explicitness, pari passu with the com- mon character on which the comparison turns. And not only does the concept rest on a synthesis, but its essen- tial function is to make a further synthesis possible . . . There is thus in the free usage of detached concepts a synthetic process always at work articulating what has been disarticulated by analysis.” 3 The process of comparison stands out clearly in many writings and experiments as perhaps the most important feature of the analyzing procedure. “By deliberate comparison I mean a mental confront- ing of the two objects, and a transition of attention from the one to the other, so as to discover some respect in which similar things differ in spite of their similarity, or in which different things agree in spite of their diversity, 1 James, 11; 550. 2 James, 11; 550. 3 Hobhouse, 10; 294. PSYCHOLOGICAL ORIENTATION 15 and also a fixing of the precise nature of this agreement or difference.”1 Stout has so ably described this activity of “com- paring” that this lengthy quotation may be pardoned: “ Comparison in all but a most rudimentary form is an ideational activity. Even when the objects compared are both present to the senses, each is scrutinised in turn. For anything more than a vague awareness of resemblance or difference, it is necessary to keep before the mind the ideal representation of the one object in the very act of examining the other. Only in this way can each detail and characteristic in turn be selected for comparison, so as to distinguish the points of difference from the points of agreement. Hence we may attribute the absence of comparison in animals in all but its most vague and rudimentary form, to the absence or extremely imperfect development of ideational activity in general. “When the process of deliberate comparison plays an important part in the mental life, it involves a corre- sponding development in conceptual thinking, in the dis- tinction of the general or universal from the particular. To compare is always to compare in some special respect. Some theoretical or practical end is to be subserved by the comparison. The difference or agreement to be dis- covered is not any difference or agreement, but one which has significance for the guidance of conduct or for the solution of a theoretical difficulty. Thus comparison takes place only in regard to the characteristics which happen to be interesting at the moment, other character- istics being disregarded or set aside as unimportant. Objects in other ways most diverse may yet in a certain respect be compared and found more or less similar, and objects in other ways most similar may be compared in a certain respect and found more or less unlike.”2 1 Stout, 26; 452. 2Stout, 26; 455-456. 16 INTELLIGENCE MEASUREMENT It may be of interest to recall at this point that Binet, with his unusually clear insight into the problems related to the development of intelligence, realized that the observation of the ways in which two things are alike is of as great a diagnostic value in determining intelli- gence level as the observation of ways in which two things are different. For that reason he devised tests for the purpose of determining a child’s capacity to note simi- larities as well as differences. Terman, recognizing the importance of both processes, has included tests which measure both capacities in his revision and extension of the Binet scale. These tests, however, deal with concrete objects. Additional tests might be devised to measure the ability to note differences, using abstract material. Thus, “To note the fall of an apple is to analyze out a com- paratively obvious feature; to distinguish falling as a feature of the moon’s revolution about the earth is still analysis, proceeding in much the same manner, but deal- ing with more difficult material and working with much more refined and elaborate tools.” 1 That there are individual differences in ability to compare and in ability to note similarities and differences seems obvious. According to James: “Some people are far more sensitive to resemblances and far more ready to point out wherein they consist, than others are. They are the wits, the poets, the in- ventors, the scientific men, the practical geniuses. A native talent for perceiving analogies is reckoned by Professor Bain (‘Study of Character,’ p. 317) and by 1 Ladd and Woodworth, 14; 606-607. PSYCHOLOGICAL ORIENTATION 17 others before and after him, as the leading fact in genius of every order.” 1 The extent to which two things which are compared may appear different, may run from one extreme to the other. Two occurrences or things or facts may be so strikingly different that discrimination is relatively easy. On the other hand, the difference in the detail of the two objects under inspection may be so fine as to escape the notice of all but the most mature or the most expert. “We all cease analyzing the world at some point, and notice no more differences. The last units with which we stop are our objective elements of being. Those of a dog are different from those of a Humboldt; those of a practical man from those of a metaphysician. . . . And when the omitted things are discovered and the unnoticed things are laid bare, it is not that the old thoughts split up, but that new thoughts supersede them, which make new judgments about the same objective world.” 2 A phenomenon closely linked with the matters men- tioned above, and of considerable significance for mental progress, is that to which Mach has called attention,3 namely, the inborn nature of experimentation in man — not the organized, thoroughly planned experimentation of the scientist, but the searching and the testing, the manipulating and the trying so characteristic of any normally developing child. An item of great relevancy at this point is the question of individual differences in this experimenting attitude, the differences in the character of the observations (analyses), and the differences in the final syntheses. 1 James, 11; 53c. 2 James, 11; 489. 3 Mach, 15; 180. 18 INTELLIGENCE MEASUREMENT Let us assume two children observing an object for the first time, one of superior and one of inferior mental ability. The little objective data which we now possess tend to show that the later imagery of this experience is markedly different in the two. The initial attitude is different. The observational procedure is different: the analyzing, the comparing, the selecting, the assimilating processes are different. “This selective activity not only differs from individual to individual, but even in the same individual it varies with the progress of his development and of his knowledge.” 1 It is evident, therefore, that the final syntheses or products of observa- tion will be different in the two. Many students of the graphic functions have frequently pointed out the devel- opment of a child’s ability in drawing through distinct stages. Thus, the first phase is that of purposeless draw- ing— a mere scribbling for scribbling’s sake; details, if observed at all, are detached entities, synthesis appearing only in its crudest form. Then follows a second stage, in which the child attempts a reproduction of objects seen, but synthetic incapacity is evident through inability to evaluate properly and place the numerous details into a reasonable whole. Thus, in drawing a picture of a human being the head is of enor- mous proportions, the limbs being appended from the chin, while other important parts of the body are omitted. In the final stage keenness of perception, a well-developed capacity for discrimination of detail, a knowledge and an experience of the laws of perspective, harmony, and balance, together with rigid self-criticism, are operative. 1 Meumann, 16; io, n. PSYCHOLOGICAL ORIENTATION 19 These steps in the development of mental ability are more or less duplicated in any variety of specific fields. For example, an average child of three can do no more than merely enumerate objects in a picture: the rela- tionships between objects are not perceived. At seven, however, he can observe that the details bear some rela- tion to one another and that some activity is portrayed. Only relationships of an obvious sort are observed. While at twelve, not only does he observe certain activi- ties, but he obtains something more than is directly presented: he reads an interpretation into the picture, and perceives the subtle meanings underlying a given situation. Each higher stage requires a higher degree of mental synthesis, of combinative power. So, again, the same is true of ability to copy a circle, a square, a dia- mond, and a design. Each one of these figures seems to require a higher form of analytic-synthetic ability for successful performance. It is in this respect that the feeble-minded are characteristically defective. The con- summation of associations or synthesizations of higher order, especially if of an abstract nature, are very difficult if not impossible for them. Meumann summarizes the differences observable in children of different age levels in this capacity to elabo- rate and assimilate their worldly experiences.1 He distinguishes three levels. On the first, synthesis is most predominant. Each object is cognized as a unit, its detail being distinguished separately in but a very inade- quate fashion. A true analytic tendency is not yet observable. Whatever meager characteristics are noted 1 Meumann, 17; 116 fit. 20 INTELLIGENCE MEASUREMENT by the child are combined into a most illusory and fantastic notion. It is this stage which Meumann designates as the “Imaginative-Synthetic Period.” This stage ends at about the age of eight or nine. Then fol- lows a period which is characterized by a pronounced tendency toward analysis. The parts, peculiarities, and relationships of things are more attentively observed. The child develops a more truthful, a more accurate knowledge of objects. Imaginative combinations, elab- orations, and interpretations become far less frequent. At about adolescence another period follows which is again synthetic, but of distinctly different character. The trend now is toward logical, reasonable combinations of impressions characteristic of the adult. “In that first period the child lives as in a fairy-world, in the third the sensing of reality appears normally active.”1 There have been many attempts to divide “mental types” into the synthetic and the analytic. Whatever one’s own reaction to the question of “types,” it is never- theless of interest to note some of the generalizations which have been made. Rignano2 distinguishes between the synthetic and analytic “mentality” as follows: the possessor of the first is the discoverer of new concepts, he prefers comparison, analogies, the study of the broader relationships of cause and effect, and gives us an insight into the broad realm of any given field of en- deavor. The analyst, on the other hand, is reflective, patient, persevering, deductive in his method; an experi- menter, he prefers long, patient reasoning, and calculations complicated and almost unending. He appears to ad- 1 Meumann, 17; 117. 2Rignano, 22; 96. PSYCHOLOGICAL ORIENTATION 21 vance prudently and surely, taking but a single step at a time. Among the synthesizers Rignano would place men such as Galileo, Newton, Faraday, Darwin, Comte, and among the analyzers, Watt, Stephenson, and Marconi. Maudsley distinguishes between assimilative and dis- criminative types. The first observes small, delicate resemblances which are imperceptible to others, the latter possesses predominantly the capacity for recognizing points of difference.1 Again, Meumann, who has devoted so much of his dis- cussion of individual differences to “types,” distinguishes between the “analytic type” of person who is especially capable in the solution of single problems, in exact and analytic observation, a critic, a classifier — and the syn- thetic type, who is the builder of systems, one who manipulates and fashions whole regions of science.2 The analyzer is concerned more with differences, the synthesizer more with similarities, with the search for similarity and analogy.3 The first is “keen-sensed,” the latter is “deep-sensed” or especially capable of noting wider and wider relationships. The highest type is that in which both attain their highest development in a single individual. Meumann distinguishes still other types, which need not concern us for the present. Some data from animal and genetic psychology have an application to the questions under discussion. Biologists have almost entirely abandoned the search 1 Maudsley, “The Physiology of Mind,” 283. 1 Meumann, 17; 159 ff. sMeumann, 17; 161. 22 INTELLIGENCE MEASUREMENT for that elusive if existent principle or trait which sepa- rates plants from animals. It would be rather generally conceded that all organisms manifest to some degree practically all the traits now claimed for higher animals.1 The difference has been maintained to be one merely of degree or proportion. This view seems to be especially agreeable to those Weismannian disciples who believe that the primordial organism possessed, in the form of germinal determiners, all the potentialities for the devel- opment of all the higher species. From the simplest one-celled organism up to man, Jennings finds evidence of perception, discrimination, choice, attention, fatigue, desire, pleasure, pain, fear, memory, habit, and even • intelligence.2 Of course, the lower down the scale the animal, the simpler are its mental mechanisms. But the germs of man’s psychic activity are assumed to exist as far down the phylogenetic line as the protozoa. There is a string of unbroken continuity between the behavior of lower and higher species. Hobhouse distinguishes four stages in mental evolution, each representing a separate degree of mental correlation and adaptation, which basically reduces to differences in the character and development of the processes of synthesis and analysis at each of the four levels.3 Ladd and Woodworth conclude that “greater power of analysis or discrimination belongs to man”4 as compared with animals. 1 Tashiro, “A Chemical Sign of Life.” 2 Jennings, 12. * Hobhouse, 10. 4 Ladd and Woodworth, 14; 555. PSYCHOLOGICAL ORIENTATION 23 All experiments upon learning, animal and human, have clearly indicated the importance of attention, dis- crimination, and association in this process. This is illus- trated in the attempt of Ladd and Woodworth to term the ‘Trial and error” learning in animals “learning by varied reaction through selection of the successful variants.” 1 Without variation in behavior-habit the right method would not have been hit upon by the animal in his learning efforts. And without attention, discrimi- nation, and association, even if chance success favored the animal, nothing would be gained which would be of future service in the same situation. James cites an instance where a dog, arriving with its master before a rowboat which they were in the habit of using, found it full of water. A sponge was generally used to bale this out. On this occasion the sponge had been left at home, about a third of a mile away. The master, disliking to make the trip, made gestures of clean- ing out the boat, at the same time saying to the dog, “Sponge, sponge; go get the sponge.” The dog ran off and brought back the desired article. To James this was evidence of nothing but contiguous association. If the dog had been unable to find the sponge and had brought back a dipper or a mop instead, “such a substi- tution would have shown that embedded in the very different appearances of these articles, he had been able to discriminate the identical partial attribute of capacity to take up water, and had reflected, ‘For the present purpose they are identical.’ ”2 It is this power to analyze 1 Ladd and Woodworth, 14; 550. 2 James, 11; 349-350. 24 INTELLIGENCE MEASUREMENT out a detail common to a series of objects, acts, or phe- nomena, which possibly differentiates man from brute, and the superior among men in intelligence from those who are inferior. This process has its analogue in ab- straction. Miss Fisher found that the experience of similarity “was the most important component detail in the process of generalizing abstraction” 1 and that the “experience of similarity and that of generality were in themselves strikingly akin.” 2 In the case of animals it is a question to what extent varieties of past experience are interpreted in the light of a new situation. Thorndike doubts whether animals possess such generalized elements of thought as ideas. And although Hobhouse’s attitude is strongly affirmative, nevertheless “if we attribute ideas to an animal, they are not ideas arrived at by any breaking-up, analysis, or other elabora- tion of what is given in perception. None of my animals (with the possible exception now and again of the mon- keys) showed the least understanding of the how or why of their actions, as distinct from the crude fact that to do such and such a thing produced the result they required. It is this want of what one may call analysis, that made, for example, the push-back bolt such a diffi- culty. What Jack or the elephant knew was, crudely, that they had to push this bolt. That the reason why they had to push it was to get it clear of the staple they obviously never grasped.” 3 How remarkably analogous is the mental functioning of the animal as here pictured with that of the high-grade moron, who knows what is right and what wrong, but 1 Fisher, 7; 97. 2 Fisher, 7; 208. * Hobhouse, io; 200-201 PSYCHOLOGICAL ORIENTATION 25 fails to grasp the “why.” Is it a question of synthetic- analytic incapacity? We shall have occasion to return to this matter again later. “If then, positively, these experiments suggest ‘prac- tical ideas,’ negatively, they strongly suggest absence of any sort of analysis in the genesis of those ideas. An animal can shift its attention to this or that object, or change within the sphere of perception; but it cannot apparently follow out the structure of any complex object with any minuteness and accuracy.” 1 Some contributions from the field of genetic psychol- ogy are illuminating. We are frequently told that the child deals with the concrete; the adult with the ab- stract. This means, presumably, that the child deals with the isolated, with objects as they have been imme- diately perceived — the adult, however, has generalized and has abstracted common properties and deals with these idealizations by means of word symbols or physio- logical set. To experience the meaning of “twenty,” or of “promise,” or of “opposite,” or of “justice,” is apparently beyond the power of children’s mental capacity. Progress in this respect comes with chrono- logical age and with the character of native mental en- dowment. It is quite apparent that “ In mental growth connection and analysis, association and dissociation, putting things together and breaking things up into parts, constantly work together.”2 There are a few pedagogical implications worth men- tioning with regard to this synthetic-analytic activity. Education, according to Royce, involves, first, “acts of 1 Hobhouse, 10; 201 2 Thorndike, 28; 219-220 26 INTELLIGENCE MEASUREMENT sensory observation, of recalling images, of repeating words, of drawing diagrams, of performing experiments, and so on, indefinitely. Then we acquire gradually the power to ‘survey at a glance/” and “this process of surveying at a glance involves a high degree of differen- tiation of our simultaneous conscious states. ”1 This ability to bring to consciousness a mass of related facts, data, information, experiences, to pick out the essentials necessary for the purposes of the particular moment, or to select and epitomize, or summarize relevant details for interpretation as a unit — that is truly mental func- tioning close to its apex of development. Meumann emphasizes the importance of combinative ability when he speaks of difficulties in work of the schoolroom, in geography, for example: “Defective capacity to learn geography may be due either to sub-normal ability to deal with concrete visual imagery (maps and the like'); or when normal visual imagery and normal memory of names is present, it may be due to an inability to combine concrete visual images with the auditory-motor images of words.”2 In the aphasias we possess excellent illustrations of total absence of specific combinative potentialities, which of course have clearly demarked neurological bases. Royce has conceived the educative process as “ an attainment of synthesis by means of analysis.” 3 And analysis “is manifestly one of the most incessantly performed of all our mental processes.”4 By emphasizing the importance of analysis and synthe- 1 Royce, 24; 254. 2 Meumann, 16; 204. * Royce, 24; 258 James, 11; 502. NEUROLOGICAL ORIENTATION 27 sis for normal mental functioning we are not claiming a berth for a new “faculty.” Evidence of every kind is again and again demonstrating the unity of mind, and the integrative character of its physical substrate: the nervous system. We cannot localize “analysis” and “synthesis.” These tendencies seem to be properties inherent in nervous protoplasm, present the very moment an aggregate of nerve cells become organized into any form of functional unit. This fact emphasizes again Wundt’s declaration that “there is, in reality, but one psychical center; and that is the brain as a whole, with all its organs. For in any at all complicated psychical process, these organs are brought into action, if not all together, at any rate over so wide a range and in such various quarters as to forbid the delimitation of special psychical centers within the functional whole.” 1 And one wonders if James was not correct when, in dis- cussing “analysis” he apologized for the short space devoted to this activity and insisted: “I think I empha- size it enough when I call it one of the ultimate founda- tion-pillars of the intellectual life.”2 3. NEUROLOGICAL ORIENTATION Our discussion of mental mechanisms invariably forces us to a consideration of the anatomical and the physiological structures underlying them. Comparative psychology has often emphasized the slight differences in the sensory capacities between man and animal. And wherever the difference has been emphasized it has 1 Wundt, 34; 218. 2 James, n; 530. 28 INTELLIGENCE MEASUREMENT often been stressed in favor of animals. Our studies of the feeble-minded reveal slight, if any differences, in the sensory capacities of normal and mentally deficient. It seems that the factors which make for intelligent be- havior do not reside in a refined sense-organ, necessarily, although refined sense-organs are extremely desirable. Intelligence is something cerebral. We, therefore, naturally look for the clearest exemplification of the activity of the analytic-synthetic tendency in the func- tion of the cerebrum. Most anatomists and neurologists agree that no true nervous elements are evident in our progress from lower to higher organisms until we reach the coelenterates. The Protozoa possess no nervous system. The Metazoa do. Jennings finds no evidence to explain the behavior of the Metazoa as different on the basis of their posses- sion of a nervous system. What the Metazoa do, the Protozoa can also do. “The possession of a nervous system brings with it no observable essential changes in the nature of behavior. We have found no important additional features in the behavior when the nervous system is added.”1 In Vorticella, Jennings found that the receptive end is ciliated peristome. Stimuli of cer- tain kinds will be transmitted and contractions of the myoid filament at the fixed end of the cell will be notice- able. In multicellular organisms the same simplicity of nervous mechanism is observed, with this exception: increased complexity of the nervous fabric is correlated with greater delicacy of individual readjustment to changes in environmental conditions. What is of espe- 1 Jennings, 12; 263. NEUROLOGICAL ORIENTATION 29 cial significance is the fact that “ the peculiar properties of the nerve cells are properties of protoplasm in general, but somewhat accentuated.”1 Each cell of our body, although there are comparatively few like itself, never- theless is capable of uniting in function with others strikingly different in structure. The nature of those conditions making for unity of function out of a diversity of structure, certainly implies a synthesis of a most subtle nature, true for somatic protoplasm as well as for nervous. The work of Sherrington, epoch-making in its contri- butions toward our understanding of nervous mech- anisms, throws some light on our question. “The nervous system in its simplest forms is diffuse — a number of scattered mechanisms performing merely local operations with much autonomy save that they have communication with their immediate neighbors across near boundaries.2 ... It is ill suited, therefore, to produce the integration of a large and complex indi- vidual as a whole.3 . . . Yet the coordination it brings about in its own local field may be strikingly effective.”4 The earthworm is a good example of a segmented or metameric nervous system. Each metamere leads an almost independent existence. But “the integrative function of the nervous system is seen to perfection in the welding together of metameres into the unity of an animal individual.”5 There are hierarchies of nervous integration paralleled by hierarchies of functional organization. “By longitudinal integration short series of adjoining 1 Jennings, 12; 280. 2 Sherrington, 25; 311. 1 Sherrington, 25; 311. 4 Sherrington, 25; 312. 5 Sherrington, 25; 3x4. 30 INTELLIGENCE MEASUREMENT segments become in respect to some one character com- bined together, so as to form in respect to that character practically a single organ.1. . . And it is in the inte- gration of long series, or of the whole series, of segments one with another, that, apart from psychical phenomena, the nervous system seems to reach its acme of achieve- ment.”2 Jennings has presented a great mass of evidence dem- onstrating the constant “feeling about” of all lower or- ganisms, the attempting of new directions, the retiring from those which are harmful, and the persisting in those which are of advantage to the organism.3 This feeling about, this avoiding and persisting, force one to grant some degree of discrimination to the animal, and once that is granted, the existence of a fundamental analytic- synthetic element logically follows. Present-day evidence has demonstrated that the neu- ron is an anatomic, genetic, physiologic, trophic, and functional unit. Each neuron is a complete cell in and of itself. Nevertheless, the complexity of interconnec- tion between neurons is beyond human comprehension. From the simplest reflex to the most complex higher thought process a basic tendency of “ get-together-ness ” and “ stay-together-ness ” is observable among neurons. And where it is absent or defective, mental progress from infancy to adulthood can hardly be conceived. The passage of stimuli through sensory pathways and the complexity of interconnection between what Sher- 1 Sherrington, 25; 344. 2 Sherrington, 25; 344. * See Jennings’ description of the behavior of an amoeba in pursuing another for the purpose of devouring it. — Jennings, 12; 16, 17. NEUROLOGICAL ORIENTATION 31 rington designates the “silent areas,” illustrate the com- plexity underlying mental mechanism. The terminal nuclei and the thalamus are among the important way- stations to cerebral connection. But “the thalamus, since it possesses many short fibres con- necting its own parts, is probably something more than a mere way-station. Apparently, the sensory impulses from the different receptors come together here and join in such a way that the impulses which pass from here to the cortex are already organized to a certain extent.”1 What function other “relay” stations or connecting links play in synthesizing and organizing primary mental states can only be conjectured. Throughout his book Sherrington stresses the interconnecting or “integrative” function of the nervous system, which makes for a unity of action out of a diversity of organs.2 In running through the evidence presented on the mental changes which result from cortical ablations, one is amazed by the contradictory results which have been found in various quarters. Careful experimentation in the last few years, notably that of Franz in this coun- try, is demonstrating with greater and greater conclusive- ness that the integrity of the cortex is necessary for the integrity of mental functioning. Meynert makes a good deal of the fact that disorganization of any portion of the cortex manifests itself in some form of psychic dis- turbance.3 Morat stresses the fact that the brain may 1 Ladd and Woodworth, 14; 93. * Sherrington, 25. * “ Populare Vortrage,” 2 ff. 32 INTELLIGENCE MEASUREMENT be regarded “a prodigy of unity” as well as “a prodigy of complexity.”1 Mach concludes that “A review of anatomic, physiologic, and psychopathologic findings forces one to the conclusion, that the integrity of con- sciousness is dependent upon the integrity of the cor- tex.”2 And finally, the careful work of Franz leads him to the generalization that, “Both the clinical and the physiological evidence points to a dependence of certain mental processes on the integrity of the frontal lobes and, in fact, on the integrity of the brain as a whole.”3 4. SUMMARY To summarize: Whether we investigate the purely mental aspects of our behavior, or whether we observe the integrating of nerve element with nerve element, we are struck with the significance of synthesis for normal mental functioning. We shall have occasion in a later chapter to consider the current definitions of intelligence, and with this new orientation we shall suggest another definition which perhaps will take us back to something more fundamental than “adaptation.” 1 Morat, 18; 1. 2 Mach, 15; 42. 8 Franz, 8; 64. BIBLIOGRAPHY 33 Bibliography 1. Bartlett, F. C., “An Experimental Study of Some Problems of Perceiving and Imaging;” British Journal of Psychology, 1916, 8: 222-267. 2. Bergson, Henri, “Creative Evolution.” (New York; Holt & Co., 1913; 407 pp.; transl. by A. Mitchell.) 3. Bolton, J. S., “The Brain in Health and Disease.” (London, Arnold, 1914; 479 pp.) 4. Book, W. F., “Psychology of Skill.” (University of Montana Publication in Psychology.) 5. Bryan, W. L., and Harter, N., “Studies in Physiology and Psychology of the Telegraphic Languages,” Psychological Review, 1899, 6: 345-375. 6. Duprat, L., “Association mentale et causalite psycholo- gique.” Revue Philosophique, 1913, 75: 452-470. 7. Fisher, Sara Carolyn, “The Process of Generalizing Abstraction; and Its Product, The General Concept.” {Psychological Monographs, 1916, vol. 21, No. 2; 213 pp.) 8. Franz, Shepherd Ivory, “On the Functions of the Cerebrum; the Frontal Lobes.” {Archives of Psy- chology, 1907, vol. 1, No. 2; 64 pp.) 9. Gregor, A., “ Untersuchungen liber die Entwicklung einfacher logischer Leistungen (Begriffserklarung). {Zsch.f. angew. Psychol., 1915, 10: 339-451.) 10. Hobhouse, L. T., “Mind in Evolution.” (London, Macmillan, 1901; 415 pp.) 11. James, W., “The Principles of Psychology.” (New York, Holt & Co., 1890; vol. 1, 689 pp.; vol. 2, 704 pp.) 12. Jennings, H. S., “Behavior of the Lower Organisms.” (New York, Columbia University Press, 1915; 366 pp.) 34 INTELLIGENCE MEASUREMENT 13. Judd, Charles H., “Psychology; General Introduction.” (Boston, Ginn & Co., 1917, [2d. ed.]; 358 pp.) 14. Ladd, George T., and Woodworth, Robert S., “Ele- ments of Physiological Psychology.” (New York, Scribner’s, 1911; 704 pp.) 15. Mach, E., “Erkenntnis und Irrtum.” (Leipzig, Barth, 1905; 461 pp.) 16. Meumann, E., “The Psychology of Learning.” (New York, D. Appleton & Co., 1913; 393 pp.; transl. by J. W. Baird.) 17. Meumann, E., “Vorlesungen zur Einfiihrung in die experimentelle Padagogik.” (Leipzig, Engelmann, 1911; 725 pp.) 18. Morat, J. P., “Physiology of the Nervous System.” (London, Constable & Co., 1914; 680 pp.) 19. Pillsbury, W. B., “Attention.” (London, Swan Son- nenschein & Co., 1908; 346 pp.) 20. Rtbot, Th., “Essay on the Creative Imagination” (Chicago, Open Court Publishing Co., 1906; 370 pp.; transl. by A. H. N. Baron.) 21. Ribot, Th., “Evolution of General Ideas.” (Chicago, Open Court Publishing Co., 1899; 231 pp.; transl. by F. A. Welby.) 22. Rignano, Eugenio, “Les diverses mentalites logiques,” Scientia, 1917, 22: 95-125. 23. Rignano, Eugenio: Qu’est-ce que le raisonnement? Scientia, 1913, 13 (supplement): 30-57. 24. Royce, Josiah, “Outlines of Psychology.” (New York) Macmillan, 1904; 392 pp.) 25. Sherrington, C. S., “The Integrative Action of the Nervous System.” (New York, Scribner’s, 1906; 411 pp.) 26. Stout, G. F., “A Manual of Psychology.” (New York, Hinds, Noble & Eldridge, 1899; 643 pp.) BIBLIOGRAPHY 35 27. Thorndike, E. L., “Educational Psychology.” Vol. 2: “The Psychology of Learning.” (New York, Teachers College, Columbia University, 1913; 452 pp.) 28. Thorndike, E. L., “The Elements of Psychology.” (New York, Seiler, 1905; 351 pp.) 29. Titchener, E. B., “A Beginner’s Psychology.” (New York, Macmillan, 1916; 362 pp.) 30. Titchener, E. B., “Experimental Psychology of the Thought-Processes.” (New York, Macmillan, 1909; 318 pp.) 31. Watson, John B., “Behavior.” (New York, Holt, 1914; 439 PP-) 32. Wundt, W., “Grundziige der physiologischen Psycho- logic.” (1910, 3 vols. [6 ed.]) 33. Wundt, W., “Lectures on Human and Animal Psychol- ogy.” (454 PP-) 34. Wundt, W., “Principles of Physiological Psychology.” (London, Swan Sonnenschein & Co., 1904; 347 pp.) 35. Ziehen, Th., “Leitfaden der physiologischen Psy- chology.” (Jena, Gustav Fischer, 1914 (Zehnte Auflage); 504 pp.) PART B THE BLOCK-DESIGN TEST THE BLOCK-DESIGN TEST1 CHAPTER I Statistics Regarding the Subjects who Were Given the Block-design Tests In the following division we shall present tables giving the chronological ages of the subjects, arranged by- source; the Binet mental ages of the subjects, arranged by source, the Binet mental ages and the intelligence quotients arranged by sex and source; the correspond- ence of chronological and mental ages, totaled separately for sex and source; the age-grade distribution, classified by sex; an age-progress table, classified by sex; nation- ality; place of birth; social class; home conditions; and teachers’ estimates of intelligence. The question- naire on p. 61 was utilized to obtain most of this infor- mation. The aim was to make certain that the group selected was typical, and if atypical, in what direction and to what extent. The results seem to show that the children selected were representative of the larger dis- tribution of children at large and consequently the final norms seem valid. Mayfield yielded children somewhat inferior, Palo Alto yielded children somewhat superior, and Menlo Park more of an average type. Table I shows the life ages of the children tested. At almost every year the cases number between 20 and 30, and the years range from 4 to 16 in the case of the pub- lic school children, and from 9 to about 37 in the case 1The complete set of material may be obtained from C. H. Stoelting Co., 3037-3047 Carroll Ave., Chicago, Illinois. 39 40 INTELLIGENCE MEASUREMENT Chronological Age Boys Girls Total 4- TO 5- 5- TO 6- 6- TO 7- 7- TO 8- 8- TO 9- 9- TO 10- 10- TO 11- 11- TO 12- 12-7 TO 13-6 13- TO 14- 14- TO 15- 15- TO 16- 16- TO 17- 17-7 TO 22-6 22-7 TO 37-6 37-7 TO over Mayfield . I 2 5 5 4 2 5 2 3 8 8 5 3 3 5 3 9 4 4 44 2 2 41 52 93 Palo Alto High 1 2 1 4 2 43 56 2 18 12 3° P.A. Intermed. 1 4 5 3 1 3 1 1 I I 12 9 21 P. A. Lytton . I 2 6 2 4 7 6 5 7 4 4 3 3 2 1 1 1 33 26 59 Menlo Park . 3 2 3 7 4 6 8 3 4 2 8 6 4 2 7 5 6 3 1 1 2 2 50 39 89 I 6 9 1413 10 18 16 11 1914 1713 15 14 16 17 18 10 10 9 88 4 2 154 138 292 Normal Total P. S. Group I i5 27 28 27 33 30 29 33 28 19 16 6 Vineland . 1 2 2 2 2 1 11 2 1 5 3 3 1 1 14 14 28 Eldridge . 1 2 2 1 1 2 2 5 11 8 9 2 1 24 23 47 1 1 2 2 2 2 4 1 1 2 1 4 3 10 14 1110 2 2 38 37 75 F. M. Total . 1 I 2 2 4 5 1 3 7 24 21 4 I 6 9 1413 10 18 17 11 20 14 1715 15 l6 18 19 22 11 119 10 9 8 5 10 14 11 10 2 2 Grand Total . I i5 27 28 28 34 32 31 37 33 20 19 13 24 21 4 192 175 367 Dark figures Female TABLE I Light figures Male STATISTICS REGARDING SUBJECTS 41 of the feeble-minded. The Mayfield cases numbered 93, the Palo Alto no, the Menlo Park 89. There are 28 feeble-minded cases included from the Vineland, N. J., Training School, and 47 feeble-minded cases from the California State Home for the Feeble-minded, making a grand total of 367 cases. Each of these was given the block designs, the two Trabue tests (B and C), the Binet test, and the dissected sentences test. The time spent in the examination of each case varied from one hour to three hours, the average being about two hours. Almost all of the examinations required two sittings, in some cases three. At no single time was a subject kept over an hour and a half. Conditions for examination were always excellent. The writer, who did all the ex- amining, always had a room apart, free from disturb- ances and distractions. In Table II are given the mental ages of the subjects examined. It will be observed that most of the ages are clustered between 6 and 13. All considered, this is an excellent range, the number of cases at each age varying from 20 to 50. In Table III are given the Mental Ages and I. Q.’s for the public school boys and girls. The modal I. Q. for both groups, separately and combined, is 100. Table IV gives the I. Q.’s for the feeble-minded. The median I. Q. for the feeble-minded falls in the 50 I. Q. group. It is evident from these tables that there is a positive correlation between increase of mental age and increase of intelligence quotient. Supposedly we would expect no correlation. But our school group is evidently se- lected. In the grammar grades there has been some 42 INTELLIGENCE MEASUREMENT Mental Age Boys Girls Total 2- TO 3- 3- TO 4- 4- TO 5- 5- TO 6- 6- TO 7- 7- TO 8- 8- TO 9- 9- TO 10- 10-7 TO 11-6 11- TO 12- 12-7 TO 13-6 13- TO 14- 14- TO 15- 15- TO 16- 16- TO 17- 17- TO 18- 18- TO 19- Mayfield . . i 2 i 5 5 7 9 8 4 4 4 II 3 6 7 3 33 I 2 I 2 I 41 52 93 P. A. High . 2 2 3 S 2 4 3 3 1 4 I 18 12 30 P. A. Inter. . 3 3 3 3 2 4 2 I 12 9 21 P. A. Lytt. . I 2 2 4 1 4 6 S 6 7 3 3 <> 2 3i 2 I 33 26 59 Menlo Park . 3 6 3 4 7 8 7 3 10 3 8 5 6 4 43 I 2 I I 5° 39 89 i 3 6 13 12 12 2022 16 13 21 17 17 20 18 10 12 7 8 8 4 6 5 5 4 3 3 l 4 I 154 138 292 P. S. Group . i 3 19 24 42 29 38 37 28 19 16 10 10 7 4 5 Vineland . . I 2 3 2 i i 2 3 1 2 1 1 2 2 2 1 1 14 14 28 Eldridge . . I 5 4 3 4 1 1 3 4 3 1 2 2 4 2 2 2 1 1 1 24 23 47 I 2 4 2 6 5 5 7 2 3 4 5 5 3 4 2 4 3 1 2 2 1 1 1 38 37 75 F. M. Total . 3 6 ii 12 5 9 8 6 7 3 2 1 1 1 X 2 5 2 9 5 11 20 1415 24 27 21 16 25 19 21 23 19 12 12 9 8 9 5 6 6 5 4 3 3 1 4 I Grand Total 3 7 14 3i 29 Si 37 44 44 3i 21* 17 11 11 7 4 5 192 175 367 Dark figures * One case no block-designs given. Female TABLE II Light figures Male STATISTICS REGARDING SUBJECTS 43 Mental Age Intelligence Quotients 26-35 36-45 46-55 56-65 66-75 76-85 86-95 96-105 106-115 116-125 126-135 136-145 Total 2-7 to 3-6 . . 0 O 3-7 to 4-6 . . I I 0 4-7 to 5-6 . . 2 1 3 0 5-7 to 6-6 . . 1 2 4 5 2 5 6 13 6-7 to 7-6 . . I I 2 2 2 6 3 3 4 12 12 7-7 to 8-6 . . I I 4 3 5 3 4 6 5 4 1 5 20 22 8-7 to 9-6 . . 2 1 4 2 2 3 7 5 1 2 16 13 9-7 to 10-6 . . I 1 2 4 4 7 3 4 5 3 1 2 1 21 17 10-7 to 11-6 . . 2 1 4 5 3 7 5 4 3 2 1 17 20 11-7 to 12-6 . . 1 5 2 6 2 3 4 1 3 18 10 12-7 to 13-6 . . 1 3 2 2 1 3 3 4 1 12 7 13-7 to 14-6 . . 2 4 1 1 4 2 1 1 8 8 14-7 to 15-6 . . 1 1 2 2 r 2 I 4 6 15-7 to 16-6 . . 3 1 3 2 I S 5 16-7 to 17-6 . . 1 2 1 1 I 1 4 3 17-7 to 18-6 . . 1 1 1 1 3 1 18-7 to 19-6 . . 1 2 2 4 I I 2 3 8 8 26 22 36 30 41 41 21 20 12 12 4 2 3 154 138 Total . . . . I 5 16 48 66 82 4I, 24 6 3 292 98-91 Dark figures TABLE III —P. S. Group MENTAL AGE AND I. Q. Modal Group = I. Q. ioo Female Light figures Male 44 INTELLIGENCE MEASUREMENT elimination of the mentally retarded, and this is especially striking in the high school grades. Our schools seem to demand higher mental ages and higher I. Q.’s for prog- ress through the grades. In the primary grades I. Q.’s fall as low as 56. In the intermediate school there was only one case below 76, and in the high school there was TABLE IV Intelligence Quotients 20 30 40 50 60 70 80 go IOO Vineland i 8 S 7 5 1 1 Eldridge 9 8 9 7 9 2 2 I Total . i 17 13 16 12 10 3 2 I 75 F. M. Group Median I. Q. = 50 not a single case with an I. Q. less than 86. Another item of importance: the upper right-hand section of Table III includes children who are accelerated men- tally but retarded pedagogically, and the lower left-hand section of the table includes children who are retarded mentally, but accelerated pedagogically. In the public school group, 189 out of the 292 have I. Q.’s between 86 and 115 — in other words, 64.7 per cent have average intelligence. Table IV gives the distribution of I. Q.’s for the feeble-minded cases. And Table V summarizes the totals in Tables III and IV. Tables VI to XII present in detail the I. Q. dis- tributions for each source, with its median I. Q. The median I. Q.’s (crude) for the various schools were, STATISTICS REGARDING SUBJECTS 45 l6 TO 25 26 TO 35 36 TO 45 46 TO 55 56 TO 65 66 to 75 76 TO 85 86 to 95 96 TO 105 106 TO 115 116 TO 125 126 TO 135 136 TO 145 Total P. S. Group .... F. M. Group .... 1 17 I 13 16 S 12 16 IO 48 3 66 2 •N M 00 41 24 6 3 292 75 Total .... 1 17 14 16 17 26 Si 68 83 41 24 6 3 367 192 TABLE V MENTAL AGE AND I. Q. P. S. and F. M. Groups Combined (Boys and Girls) 46 INTELLIGENCE MEASUREMENT Mayfield, 90; Palo Alto High, no; Palo Alto Inter- mediate, 100; Palo Alto Lytton, 100; Menlo Park, 90; Vineland, 45; Eldridge, 50. TABLE VI Mental Age Intelligence Quotients Total 40 So 6o 70 8o go 100 no 120 4 X 1 5 I I 2 6 I I I 3 1 5 7 i 2 2 2 I I 1 2 5 7 8 I 2 2 3 1 3 3 1 1 9 8 9 I I 2 1 2 1 4 4 IO i 2 I 3 2 1 4 1 4 II XI I I 3 2 1 1 3 6 12 3 2 I 1 1 2 7 3 13 i 2 2 1 3 3 14 I 2 1 2 IS 1 I 1 I 2 16 1 I i 2 I 4 6 ii 15 10 7 6 16 ,5 6 2 1 41 52 Total i 3 IO 26 17 22 11 3 93 Mayfield Cases Median I. Q. = 90 TABLE VII Mental Age Intelligence Quotients 70 80 sfo IOO no 120 Total XI . 1 1 1 2 1 3 3 12 1 2 I 2 3 3 13 • • 1 X 2 14 • • 1 1 1 2 1 4 2 IS • • 16 1 I 1 2 1 2 3 3 2 2 2 2 1 12 9 Total . 1 3 5 5 4 3 21 Palo Alto Intermediate Median I. Q. = ioo Boys Light figures Girls Dark figures STATISTICS REGARDING SUBJECTS 47 TABLE VIII Palo Alto High Mental Age Intelligence Quotients Total 90 IOO no 120 130 140 14 . . 2 2 IS • • I I 1 I I 2 3 16 3 I 2 1 S 2 17 • . 1 2 I 1 1 I 4 3 18 . . I 1 1 1 3 l 19 . . 1 2 2 4 I 1 3 4 2 .3 3 4 3. .3 1 3 18 12 Total . 4 6 6 7 4 3 30 Median I. Q. = no Boys Light figures Girls Dark figures TABLE IX Mental Age Intelligence Quotients Total 8o go IOO no 120 130 5 • i I 6 . i I i 1 2 2 7 2 2 1 4 I 8 . i I i 2 I i i 2 4 6 9 • i I i 4 3 i 5 6 IO i 2 3 i 2 I 7 3 ii I i i 2 I 2 I 3 6 12 i i 2 13 3 I 3 I 14 i 1 2 15 • 1 1 1 * 8 3 15 9 6 4 2 5 1 1 33 26 Total 5 ii 24 IO 7 2 1 59 Palo Alto Lytton Light figures Median I. Q. = ioo Boys Girls . Dark figures 48 INTELLIGENCE MEASUREMENT TABLE X Mental Age Intelligence Quotients Total 6o 70 8o go IOO no 120 6 . . i 2 4 I I 3 6 7 • • i 3 2 I 3 4 8 . . i 2 i i 2 2 2 2 2 7 8 9 • • I 2 i 3 2 I 7 3 xo . . I 3 3 3 I 2 io 3 ii . . I 2 1 2 2 2 I 2 8 5 12 . . I I I 3 I I I I 6 4 13 • • 2 I 2 2 4 3 14 . . I I I I 2 IS • • I I 16 . I I 2 .3 2 12 2 IS 14 13 I2 5 5 2 2 5° 39 . Total • 2 5 14 29 25 IO 4 89 Menlo Park Median I. Q. = 90 TABLE XI Eldridge Mental Age Intelligence Quotients 30 40 So 6o 70 8o go IOO Total 4 ... I i 5 ... 4 4 I 5 4 6 ... i 4 I i 3 4 7 . . . i i i I 8 ... 3 4 3 4 9 . . . i 2 I 3 i IO . . . 2 2 2 2 ii ... 4 2 4 2 12 2 2 13 . . . 2 2 14 • . . I I IS • • • I I 16 I I 5 4 3 5 4 5 5 2 5 4 2 I I I 24 23 Total . 9 8 9 7 9 2 2 I 47 Median I. Q. = 50 Boys Light figures Girls Dark figures STATISTICS REGARDING SUBJECTS 49 TABLE XII Vineland Mental Age Intelligence Quotients 20 30 40 SO 6o 70 8o Total 3 • • i 2 I 2 4 • • 2 2 I 3 2 S • • I 1 I I 6 . . 2 2 I 2 3 7 • • I I i I 2 8 . . I i I I 9 • • 2 I i 2 2 IO . 2 2 ii . . I I 12 . I I i 3 5 2 3 .5 2 2 3 I I 14 14 Total i 8 5 7 5 I I 28 Median I. Q. = 45 Boys Light figures Girls Dark figures In Table XIII are presented the mental age and chronological age distributions for the public school group. It is evident from this table that there is a some- what larger percentage of those who are retarded men- tally than accelerated: 36 (12 per cent) are accelerated more than one year, and 81 (28 per cent) are retarded more than one year. In Table XIV the data of Table XIII are summarized for years of retardation and ac- celeration. It will be observed that 59 per cent are at age mentally, or within one year; 22 per cent are within two years; 9 per cent are within three years; 7 per cent are within four years; 2 per cent within five; and of 1 per cent within six years of their mental age. 50 INTELLIGENCE MEASUREMENT Chrono- Mental Age Total Age 3 4 S 6 7 8 9 IO II 12 13 14 IS 16 17 18 19 5 I 1 1 6 X S 7 1 1 6 9 IS 7 I i 3 5 5 7 5 14 13 27 8 I 3 4 1 2 9 2 3 1 2 IO 18 28 9 1 2 4 2 6 5 4 1 2 16 11 27 IO 1 1 6 4 2 2 5 4 2 2 2 I 1 19 14 33 XI 1 2 3 6 4 4 4 2 2 I I 17 13 30 12 1 1 2 2 1 2 4 3 3 3 T 2 3 1 IS 14 29 13 1 2 1 3 4 2 4 3 1 3 ; x 2 I I 1 1 16 17 33 14 1 4 3 3 1 1 4 1 2 2 I 2 1 2 18 10 28 IS 1 1 2 2 3 2 I I I I 1 2 I IO 9 19 16 1 2 1 2 I I I 2 1 1 2 1 8 8 16 17 1 1 1 1 I 1 4 2 6 I 3 6 13 12 12 20 22 16 13 21 17 17 20 18 IO 12 7 8 8 4 6 5 5 4 3 3 1 4 I Total I 3 i9 24 42 29 38 37 28 19 l6 IO IO 7 4 5 154 138 292 Dark figures CHRONOLOGICAL AND MENTAL AGES Girls TABLE XIII (P. S. Group) Light figures Boys STATISTICS REGARDING SUBJECTS 51 Mental Age Boys Girls Total 5 yrs. . 4 “ 3 “ • 4 4 Above 3 2 3 1 6 3 - 36 2 “ . IO 13 23 i “ 26 20 46 At Age 41 43 84 173 i yr. 25 18 43 2 yrs. . 21 19 40 Below - 3 “ • 12 13 25 83 4 “ • 9 6 15 5 “ • I 1 2 6 “ . 1 1 Total . 154 138 292 TABLE XIV In Graph i is presented graphically the retardation and acceleration of the 292 public school cases. A skew is observable toward the right. This is again manifest in Graph 2, which graphically represents the distribution of I. Q.’s for the same group of children. In making a comparison between the grouped distributions of I. Q. obtained by Terman in his revision of the Binet for 905 cases and our results, we note the following: Ter- man found 35 per cent having I. Q.’s above average, in our cases 25.4 per cent were above average; he also found 33.9 per cent average (96 — 105 I. Q.), in our cases 28 per cent were average; and he found 31.3 per cent below average, while in our cases 46.6 per cent were below average. Our inferior group is 15 per cent larger, the average group is about 6 per cent smaller, and the superior group is about 10 per cent smaller. The fact that Terman excluded the foreign-born, which have been included in our data and amount to about 5 per 52 INTELLIGENCE MEASUREMENT Number of Children at, Above and Below Age GRAPH 1 Public School Group Number .Percent Below At Age Above Distribution of I. Q. GRAPH 2 Public School Group Number Percent Class 100 Includes I. Q.s from 96-105 Intelligence Quotient 53 STATISTICS REGARDING SUBJECTS Grade uAL I 2 3 4 s 6 7 8 I II III 5 6 I 6 9 1 6 7 9 7 5 5 i 14 13 8 3 5 .8 I 7 10 18 9 i 2 2 8 7 3 2 2 16 11 IO 2 I 8 3 5 3 3 6 I I 19 H ii 2 I 5 2 8 5 2 3 2 17 13 12 I 2 I 4 I 3 4 3 7 1 1 1 15 14 13 2 2 2 4 3 3 9 3 * 2 2 16 17 14 I 3 i 3 4 7 3 4 2 18 10 15 2 I 5 2 I 1 2 1 10 9 16 3 2 2 3 3 2 1 8 8 17 2 2 2 4 2 21 19 4 16 20 19 !7 8 20 14 ,!3 12 II 23 20 14 11 8 6 4 1 I 1 4 !38 Total • • • 40 30 39 25 34 25 34 34 19 10 2 292 Dark figures AGE-GRADE DISTRIBUTION TABLE XV Girls Light figures Boys 54 INTELLIGENCE MEASUREMENT cent of the public school cases, would help account for the discrepancy. We have also made no eliminations because of race or nationality. As Pintner has so ably stated, the mere fact of large numbers of cases is no safe- guard for reliability of standardization; and in obtain- ing accurate norms, individuals of all classes and degrees should be included.1 We have stressed careful technique rather than multiplicity of cases, or perfection in sam- pling. Table XV is the age-grade distribution of our public school cases. What is striking here is the practically symmetrical distribution as compared with the skewed curve for the mental ages and I. Q.’s. This is clearly brought out in Table XVI, which summarizes briefly the data of Table XV. It will be observed that 35 per cent are at age pedagogically, 31 per cent are acceler- ated, and 34 per cent are retarded. The percentage at or within one year of grade is 83 per cent. TABLE XVI Boys Girls Total Per Cent 3 yrs. . . i 1 4 Above grade - 2 yrs. . . 8 6 14 47 I yr. . . 3i 45 76 26.0 At age for grade . . S3 49 102 349 i yr. . . 38 26 64 21.9 2 yrs. . 17 9 26 9.0 Below grade 3 yrs. . . 6 2 8 27 4 yrs. . . 1 s yrs. . . I X •4 Total 154 138 292 100.0 1 See R. Pintner and D. G. Paterson, “A Scale of Performance Tests,” pp. 73 ff. 55 Years in School Grades Less THAN One I 2 3 4 s 6 7 8 9 IO II 12 Total i H 8 3 8 7 3 21 19 2 I 2 12 12 I 2 1 14 17 3 • 8 IS 9 5 2 20 19 8 4 • 7 2 6 4 4 2 17 5 • 2 8 6 S 2 0 3 I I 20 14 6 . 1 00 10 4 2 2 I I 1 13 12 7 • 2 6 7 3 II I I I 2 11 23 8 . 2 2 8 6 6 4 3 1 r 1 20 14 I 2 3 7 1 2 3 11 7 II 1 1 1 1 4 2 6 4 III 1 I 1 1 ii 8 4 10 19 23 23 15 20 12 16 15 18 14 13 23 18 9 7 6 4 3 1 154 138 Total • 19 14 42 38 32 31 32 36 27 13 7 1 292 Dark figures GRADE-PROGRESS DISTRIBUTION TABLE XVII Girls Light figures Boys 56 INTELLIGENCE MEASUREMENT Tables XVII and XVIII are concerned with the cor- relations between grade and progress, or the number of years spent in school: 40 per cent had made normal progress, 41.5 per cent had made accelerated, and 18.5 per cent had made retarded progress. The percentage TABLE XVIII Boys Girls Total Per Cent f 4 yrs. . . Accelerated I 3 yrs. . Progress | 2 yrs. . 1 1 yr. • • Normal progress Retarded f 1 r‘ v, <2 yrs. . Progress | _ 2 1 4 54 60 29 2 2 2 IO 48 57 15 5 1 2 3 14 102 X17 44 7 3 •7 1.1 4-7 349 40.0 I5-I 2.4 1.1 Total . 154 138 292 100.0 making normal progress, or within one year of it, amounted to 90 per cent. The numbers making rapid progress are unusually large. This is accounted for by the fact that a good part of the testing came in February and March (1918) when children had just been promoted to a new grade. They were thus given credit for progress in that grade in which they had not yet made any progress at all. Taking this into account, the grade- progress distribution is of about the same type as the age-grade. In Table XIX are given the numbers and per cents of boys and girls who are at grade or within one year of it by chronological age (termed “in the right grade”), and who are between 86 to 115 I. Q. (termed “right I. Q. ”). It is clear from the table that 60 per cent of the STATISTICS REGARDING SUBJECTS 57 TABLE XIX GRADE LOCATION AND I. Q. Number Per Cents Total PerCent Boys Girls Boys Girls In right grade and of right I. Q.. . 91 85 59% 62% 176 60% Neither right grade nor right I. Q. . 25 12 16% 9% 37 13% Right I. Q. only . 7 6 5% 4% 13 4% Right grade only . 3i 35 20% 25% 66 23% Total . 154 V 138, 100% 100% 292 100% 292 By “Right Grade” is meant at grade or within one year of it for chronological age. By “Right I. Q.” is meant an I. Q. between 86 to 115. children are what may be termed “average” and these help stabilize any tendency toward deviation from the absolute norm. In Table XX is given a list of geographical divisions and the number claiming descent from the nations of that region. Ranked for frequency, the leading nationali- ties came in the following order: North European, American, and combinations of North European and American. These accounted for over 80 per cent of all the cases. The descendants from northern groups num- bered 80.4 per cent, from southern groups 11.7 per cent, Orientals 3.4 per cent and from those not stating 4.5 per cent. The data on birthplace by states, summarized for geographical division, and for birthplace in California 58 INTELLIGENCE MEASUREMENT or outside of the state, are here presented: 74 per cent were born in California, 26 per cent were born elsewhere. The Pacific Coast States contributed 76.5 per cent, Mountain States 5.2 per cent, East North Central 4.5 NATIONALITY AND BIRTHPLACE TABLE XX Number Per Cent (i) North European 108 37-0 (2) South European 22 7.6 (3) American 91 3II (4) Oriental 10 34 (5) American and N. European 36 12.3 (6) American and S. European.... 5 1-7 (7) N. European and S. European . 7 2.4 (8) ? or not stated 13 45 Total 292 100.0 per cent. The smallest numbers came from the East South Central States (.7 per cent) and from the New England States (o per cent). Tables XXI to XXIII and Graphs 3 to 5 give the results of teachers’ estimates of intelligence, home con- ditions, and social class. The writer has devised a series of tables for grouped measures of variability which are given in the appendix and which are here utilized for the purpose of comparing the percentages actually found with what one would expect theoretically. It will be noted that the average discrepancy for intelli- gence estimation is only 2 per cent, for estimation of home conditions 3 per cent, and for social status 4 per cent. This increase is to be expected, for to teachers, intellectual performance is under their observation STATISTICS REGARDING SUBJECTS 59 continually, and this is not as true for home conditions or social status. TABLE XXI TEACHERS’ ESTIMATES Number Per Cent Theoretical Expectation Discrepancy Very inferior. . 4 14 0.2* + 1.2 Inferior .... II 3 7 4.0 -0.3 Below average S2 17.8 24.O —6.2 Average .... 133 455 43-6 + i-9 Above average 68 23.2 24.0 —0.8 Superior .... 21 7-3 4.0 +3-3 Very superior . . 3 1.1 0.2 +0.9 Total .... 292 100.0 100.0 Intelligence Average (A. M.) Discrepancy = 2.1% * See Appendix I. TABLE XXII TEACHERS’ ESTIMATES Home Conditions Number Per Cent Theoretical Expectation Discrepancy Very inferior. . 2 0.7 0.2* +o-S Inferior .... 17 6.0 4.0 + 2.0 Below average 57 20.2 24.O “3-8 Average .... 113 40.0 43 6 -3-6 Above average 56 19.6 24.O -4.4 Superior .... 26 9.2 4.0 + 5-2 Very superior . 12 43 0.2 +4-i ? 9 Total .... 283 100.00 100.0 Average Discrepancy = 3.4% * See Appendix I. 60 INTELLIGENCE MEASUREMENT TABLE XXIII TEACHERS’ ESTIMATES Social Status Number Per Cent Theoretical Expectation Discrepancy Very inferior. . 5 1-7 0.2* + i-5 Inferior .... 16 57 4.0 + i-7 Below average 47 16.8 24.O -7.2 Average .... 132 47-3 43-6 +3-7 Above average 48 17.4 24.0 —6.6 Superior .... 21 7-5 4.0 +3-5 Very superior . 10 3-6 0.2 +3-4 ? 13 Total .... 279 100.0 100.0 Average Discrepancy = 3.9% * See Appendix I. TEACHER’S ESTIMATES Intelligence GRAPH 3 Per Cent Number Very Infer. Infer. Bel. Aver. Aver. Above Aver. Super. Very- Super. STATISTICS REGARDING SUBJECTS 61 Home Conditions Per Cent GRAPH 4 Number Social Status Per Cent GRAPH 5 Number Very Infer. Infer. Bel. Aver. Aver. Above Aver. Super. Very Super. Summing it all up, we have tested a fairly representa- tive group of school children, on the whole perhaps not markedly different from average children in other parts of this country. Sample of Questionnaire To the Teacher The information rendered on this blank will be held strictly confidential, will be used for statistical purposes 62 INTELLIGENCE MEASUREMENT only and without the mention of any child’s name. The information will aid greatly in the standardization of a series of block-design tests. 1. Name of school 2. Name of pupil 3. Date of birth 4. Grade (when test was made) 5. Years attended school... Grades skipped... Repeated... 6. Place of birth (what state if American, what country if foreign). 7. Descendant of what nationality (E.g., Scotch-Irish, Portuguese, German-American, etc.) 8. Language spoken at home 9. Occupation of father 10. Quality of the child’s work (as compared with average children for this grade). (Write appropriate number, see rating scale) 11. Teacher ’ s estim ate of the child’s intelligence (as compared with aver- age children of the same age). (Write appropriate number, see rating scale) 12. Home conditions (con- sider neatness, size, comfort, provision of life necessaries, rela- tions between the par- ents, parental super- vision). (Write number) Rating Scale In your ratings indicate 1. Very Inferior by 4 2. Inferior by 5 3. Below Average by 6 4. Average by 7 5. Above Average by 8 6. Superior by 9 7. Very Superior by 10 STATISTICS REGARDING SUBJECTS 63 13. Social class (consider culture, intelligence, social posi- tion of the group from which the child comes). (Write number) 14. What is the character of the child’s work in the following school subjects (use rating scale). (Write number) 1. Reading 2. Writing 3. Spelling 4. Language 5. Arithmetic 6. History 7. Geography 8. Drawing 9. Nature Study 10. Music 11. Manual Training 12. Household Arts 13. Science 14. Deportment 15. If this child were given a mental test involving chiefly the use of language, or the ability to understand and handle language symbols (as contrasted with a test requiring silent observation and performance), would you expect him (her) to pass Very low Low Below Average Average Above Average High Very High Note. — Put an X before the appropriate word 16. Additional information which will throw light on the child’s intelligence, school success or failure, social status, peculiarities of any sort, etc. will be especially welcome and appreciated. We thank you. CHAPTER II The Test Material I. THE MATERIAL (a) The Blocks The blocks which are used are manufactured by The Embossing Co., are called “Color Cubes,” and may be secured at any of the large department stores and at the various distributing centers of Milton Bradley’s. There are sixteen cubes of one inch dimension and all are painted as follows: One side red, One side blue, One side white, One side yellow, One side blue and yellow (divided on the diagonal), One side red and white (divided diagonally). The character of the colors is indicated on the pages of designs printed in this monograph. A slight difficulty, experienced by possibly one or two subjects out of every one hundred, was a just perceptible but nevertheless dis- concerting difference in shade between the blue and yel- low on the full faces and the same colors on the diagonal sides. This can be remedied in the later standardization of the test material. One set of six blocks will last through the examination of from four to five hundred 64 THE TEST MATERIAL 65 children without showing much wear and tear. After that the cubes can be repainted without difficulty. It is interesting to watch the response of children and even adults when they are given colored cubes to handle. There is no doubt that an appeal exists which touches the roots of some very fundamental original tendencies. Of all the subjects tested, not one has manifested any absence of a desire to combine these cubes in some fashion. The experimenter needs only to direct this natural interest toward a specific end and then apply a scientific measuring technique to evaluate the results. (b) The Designs On pages 66-67 are presented the designs utilized in this study. The Roman numerals refer to the num- bers given the designs during the time when the tests were being standardized. The Arabic numerals designate the final numbering of each design. The original number was thirty-five, but fifteen were eliminated in a few of the early preliminary testings. The designs are graded in difficulty which increases by modifying the designs at various stages in the following manner: 1. By the use of the full colors; 2. By the use of few diagonaled sides; 3. By the use of all diagonaled sides; 4. By turning the design on one of its corners; 5. By eliminating the outside boundary line; 6. By increasing the number of blocks to be used; 7. By increasing dissymmetry in design; 8. By decreasing the number of different colors used in each design. Design 1 Design 7 Design 11 Design 2 Design 3 Design 3 Design 12 Design 4 Design 9 Design 13 Design 5 red Design 10 white Courtesy Psychological Review Co. yellow Design 6 ■blue THE TEST MATERIAL 67 Design 14 Design 16 Design 15 Design 17 red Courtesy Psychological Review Co. White yellow Trial Design A blue 68 INTELLIGENCE MEASUREMENT To perform the test, utilizing the twenty designs, one averaged about an hour or an hour and a half. In the final revision three designs have been eliminated, leaving seventeen, thus decreasing somewhat the time necessary to apply the tests with no significant decrease of relia- bility. The criteria for rejection were based on correla- tions with those arrays of evidence presuming to yield an index of intelligence, such as is obtained through the use of the Binet scale, and also upon the basis of the diagnostic value of each design, determined by the pro- gress of its curve with increasing chronological age. The results at present indicate that the block designs are as good as any single test in the Binet scale (though better, perhaps, in the sense of diagnostic value), as good as the Trabue Language Completion Tests, or any other similar single type test, whether involving the use of language or whether mere performance. The designs, appropriately colored, are printed on medium-thick, white, semi-gloss cardboard. The di- mensions of the card are three by four inches. The printed designs, placed in the center of the card, are one- fourth the size of the actual designs when the cubes are used. In other words, the face of a cube represented on the designs is only one-half of an inch on each of its sides. Thus design No. i is one inch square, design No. io is one and a half inches square, and design No. 14 is two inches square. The writer has found it of assistance to place in the lower right-hand corner the time limit for each design. These values follow: THE TEST MATERIAL 69 Time Limits for Each Design TABLE XXIV Design (Number) Time Limit (Minutes) Design (Number) Time Limit (Minutes) Design (Number) Time Limit (Minutes) I 7 • • 2 13 • • 3'A 2 i Vi 8 . . 2 14 • • s'A 3 • • i A 9 • • 2 IS • • 4 4 • • 2 IO . 3 16 4 5 • • 2 ii 3^ 17 .. . 4 6 . . 2 12 3^ The time limit set for each design is about one minute longer than the time within which a correct response may reasonably be expected. It may be of interest to remark that if the full limit is allowed on each test the working-time totals only forty-five minutes for all of the seventeen designs. With practice an examination should average about thirty to forty minutes. In some cases it may take only fifteen or twenty minutes, in others perhaps an hour. (c) The Score Card and the Method of Scoring In the succeeding table are presented the score values of each of the seventeen designs and the number of score points to be deducted if a design is successfully com- pleted with excess time and with excess moves. To clarify the table, one or two illustrations will be utilized. For example, design No. 2 has a score value of 5. This full amount is attained if a reagent completes the design successfully in less than 31 seconds and with less than 7 moves. If 31 or more seconds are utilized, one point is deducted from the score, and if 7 or more 70 INTELLIGENCE MEASUREMENT moves are made an additional point is deducted. Take again design No. 13, which has a score value of 9. This full amount is attained if the subject completes the de- sign successfully in less than 2 minutes and 21 seconds, and with less than 31 moves. If completed between TABLE XXV Score Card Design No. Score Value Points Points to be Subtracted Excess Time Excess Moves 1 Point i Point 2 Points I 3 21" and over 6 and over 2 5 31" and over 7 and over 3 6 21"to 35" 36 " and over 8 and over 4 7 31" to 1' 0" i' 1" and over 10 and over 5 7 36" to 1' 5" 1' 6" and over 11 and over 6 7 36" to 1' 0" i' 1 "and over 12 and over 7 7 41" to i'io" 1'11" and over 11 and over 8 8 41"to 55" 56" and over 10 and over 9 9 56" to i'io" 1'11" and over 15 and over IO 9 I'56" to 2'io" 2'n" and over 22 and over ii 8 I'46" to 2'3o" 2'3i" and over 19 and over 12 9 2'26" to 2'4o" 2'41" and over 30 and over 13 9 2'2l" tO 2'33" 2'34" and over 31 and over 14 9 2'26" tO 2'4o" 2'41" and over 32 and over IS 9 2'4l" to 3' 0" 3' 1 "and over 32 and over 16 IO 2'4l"t03' 5" 3' 6" and over 31 and over 17 ii 2'4l"tO 2'55" 2'56" and over 30 and over Maximum score —133 points. 2 minutes 21 seconds and 2 minutes 33 seconds, one point is deducted; and if 2 minutes 34 seconds or more are spent on the problem, two points are deducted. And if 31 or more moves are made an additional point is deducted from the score value of the design. The scoring of a performance is a very simple matter. This will be self-evident from the following examples: THE TEST MATERIAL 71 Example one: Design No. 7 successfully completed in 1 minute and 23 seconds and at the end of 9 moves. Score 7, for successful completion, less 2 points for excess time. Final score 5. Example two: Design No. 10 successfully completed in 1 minute 48 seconds, and after 19 moves. Score 9, for successful completion. No deductions for excess time or excess moves. Final score, 9. Example three: Design No. 16, successfully completed in 3 minutes 27 seconds, and after 48 moves. Score 10, for successful completion. Deduct 2 points for excess time, and one point for excess moves. Final score 7. It may be worth remarking that successful perform- ance, speed, and what may be termed accuracy are combined in the final score. Successful performance receives greatest weight, speed next, and accuracy next. The weight ratio as explained elsewhere in the mono- graph is roughly 4:2:1. This ratio has been empi- rically determined. The prevalent opinion that speed and accuracy cannot be combined in one score, does not hold with the Block-design Tests. The writer felt that success, speed, and accuracy each had its own diagnostic importance, and in order to make the tests most effective all should, and must, be taken into ac- count in the final score summation. For a more detailed discussion of this matter see a later section. (1d) The Norms The procedure involved in obtaining norms for the different designs was quite a complicated one, requiring a great deal of careful statistical work. In this effort 72 INTELLIGENCE MEASUREMENT the writer utilized the currently accepted standardization methods, with but slight modification. An explanation of the general procedure utilized, together with a de- scription of various methods of checking the results has Mental Age Equivalents of Score Points GRAPH 6 SCORE POINTS Courtesy Psychological Review Co. AGE been left for a later chapter. Suffice it to say that the score points mentioned in Table XXV are to be inter- preted in the same light as those of Buckingham in his standardization of his Spelling Tests, of Trabue in his standardization of his Language-Completion Tests, and THE TEST MATERIAL 73 of Woody in his standardization of his Arithmetic Tests. In this section the final results, merely, will be presented. Graph 6 is the curve indicating the scores to be expected at the various ages from 3 years to 19 years and 6 months. This curve has been smoothed but slightly TABLE XXVI Mental Age Equivalents of Score Values Score Points Mental Age Score Points Mental Age Score Points Mental Age Score Points Mental Age o 5~ 3 or -below 33 10- 9 66 13- 5 99 15- 9 i 5“ 7 34 10-10 67 13- 6 100 15-10 2 6- 0 35 10-11 68 13- 6 101 15-n 3 6- 3 36 11- 0 69 13- 7 102 16- 9 4 6- 6 37 11- 1 70 13- 8 103 16- 1 5 6- 9 38 11- 2 7i 13- 9 104 16- 2 6 7- 0 39 11- 3 72 13- 9 i°5 16- 3 7 7- 3 40 11- 4 73 13-10 106 16- 4 8 7- 6 4i 11- 5 74 13-n 107 16- s 9 7- 8 42 11- 6 75 14- 0 108 16- 7 IO 7-10 43 11- 7 76 14- 1 109 16- 8 ii 8- 0 44 11- 8 77 14- 1 no 16- 9 12 8- 2 45 11- 9 78 14- 2 III 16-10 13 8- 4 46 11-10 79 14- 3 112 16-11 14 8- 5 47 ii-ii 80 14- 4 113 17- 1 IS 8- 7 48 12-0 81 14- 5 114 17- 2 16 8- 9 49 12- 1 82 14- 6 ns 17- 4 17 8-10 50 12- 2 83 14- 7 116 17- 5 18 9- 0 5i 12- 3 84 14- 7 117 17- 6 19 9- 1 52 12- 4 85 14- 8 118 17- 8 20 9~ 3 53 12- 5 86 14- 9 119 17- 9 21 9- 4 54 12-6 87 14-10 120 17-10 22 9- 6 55 12- 7 88 14-11 121 18- 0 23 9~ 8 56 12- 8 89 15- 0 122 18- 2 24 9“ 9 57 12- 9 90 15- 0 123 18- 3 25 9-11 58 12-10 9i 15- 1 124 18- S 26 10- 1 59 12-10 92 15- 2 125 18- 7 27 10- 2 60 12-11 93 15- 3 126 18- 9 28 10- 3 61 13- 0 94 15- 4 127 18-n 29 10- 4 62 13- 1 95 15- 5 128 19- 1 30 10- s 63 13- 2 96 15- 6 129 19- 3 31 10- 7 64 13- 3 97 15- 7 130 19- 7 32 10- 8 65 13- 4 98 15- 8 131 19-n 74 INTELLIGENCE MEASUREMENT within the range of ages below io, though rather con- siderably from 15 to 19. This was necessarily the result of a deficiency in the number of cases at the higher ages. The median score is represented by a circlet placed above each age. In Table XXVI are presented the mental age equiv- alents of each score from 1 (mental age 5 years and 7 months) to 131 (mental age 19 years and n months). These values were derived from Graph 6. 2. THE DIRECTIONS EOR APPLYING THE TESTS Preliminaries: Seat the S comfortably at a table, noting that his visual angle when working with the tests is not less than 45 degrees. Be sure that no designs are visible in your preliminary instructions, nor more than a single design at any one time. The blocks which are not being utilized should be kept in a box, apart, so that they are either invisible to the S, or if visible, the blocks should be arranged so that the top sides are all of the same color. Method: Part i. For Subjects Who Can Understand Spoken Language (Section A) Take a block. (Instructions to S are placed in quotation marks. For design i four blocks will have been removed from the box.) “Here are some blocks — give me the name of the color on this side.” Sides with the full colors are presented first. Place your finger on the side designated. After S has responded, turn to another side. “And what is the color on this side?” — “Now the color here?” — “And what is the THE TEST MATERIAL 75 color here? ” — If S has succeeded in naming the colors correctly, proceed with the experiment. (If he has failed, further instructions are given below, in Part 2.) Then the experimenter explains: “Now on this side we have blue and yellow (point), and on this side red and white (point). And all the blocks are painted in the same way.” (Section B) “What you are to do is this: Take these blocks” (shuffle them so that when finally placed before S, no more than one quarter of the blocks have topside colors which are present in the design, the separate blocks being placed apart, flat on table, and not piled one on top of another), “pick out the right colors, put them together, and make them look, on top, just like this” (point to design 1). Give no further hints or sug- gestions if the directions have been understood. Caution: Be sure that all the blocks are thoroughly shuffled before the design is presented. The purpose is to eliminate the possibility of studying the design before being ready to begin work with the cubes. (Section C) If S has not understood what is meant, E may perform trial design (A)x slowly, using pantomime freely, S watching closely, after which S is requested to repeat the operation. This may be repeated any num- ber of times until S understands. When he does, proceed with the designs in order, beginning at (Section B), and continuing with (Section D). 1 Trial design (A) is represented on the pages with the other designs and is used only when under the provisions of Section C further pre- liminary explanation is necessary. Trial design A is a four-block design, two full white sides above, two full yellow sides below. 76 INTELLIGENCE MEASUREMENT (Section D) After the first design has been com- pleted or failed, the blocks are again shuffled, observing the cautions in (Section B), and the S is told again to “take these blocks, pick out the right colors, put them together, and make them look on top just like this.” (Point to design No. 2.) These instructions remain the same for all the designs. The S is not told at any time the number of the blocks he is to use. Record: Both time and moves are recorded. A move is counted when a block is given its initial position on the table. Each separate and distinct change in the position of a block is counted a move. Sometimes a child will make three or four changes in the position of a cube, the topside remaining the same color (especially true of diagonal sides, e.g. red — white). But each change in position is counted a separate move. If success is not attained within the time limit, no credit is assigned. The time limits are indicated on the design cards. The whole test is not regarded as complete unless there are, ordinarily, at least five consecutive" failures on designs after the last success, and where doubt exists as to the inability in the later designs, give as many designs beyond the last success as is deemed wise. Part 2. For Subjects Who Do Not Know the Names of the Colors Take all the blocks out of the box and place on the table so that the single-colored faces are all on the top side of the cubes. Have an equal number of reds, yellows, blues, and whites. Point to a red-topped THE TEST MATERIAL 77 block and ask the child to point to all the blocks that have the same color on top. Do the same for the other three colors. If the child can distinguish the colors, proceed with the test at Section B. Part 3. For Subjects Who Cannot Understand Spoken Language By means of gestures and pantomime go through the procedure in Part 2. If S can distinguish the colors, proceed with Section C, and through the various designs. The method of recording remains the same. CHAPTER III Standardization Technique 1. The Year-Scale Method 2. The Percentile Method 3. The Point-Scale Method 4. The P. E. or Linear Projection Method The past few years have seen such a rapid develop- ment in the technique of scale-making for the purpose of measuring mental capacities and pedagogical progress that any reasonable discussion of this branch of psycho- logical and educational statistics would be entirely too extensive and consequently out of place in this mono- graph. However, there are four distinct methods which have had more or less ready application and it is to these alone that the writer will confine his discussion. I. THE YEAR-SCALE METHOD This is the method which has been utilized in standard- izing the various versions of Binet-Simon Measuring Scale for Intelligence. After tests have been selected and applied to large numbers of unselected children of different ages, each test in the scale is considered sepa- rately and the percentage passing the test at the various life ages is determined. The fundamental assumption is that if a test is a measure of intelligence development, there will be an increase in the per cent passing the test with increase of age. (Increases due to differences of 78 STANDARDIZATION TECHNIQUE 79 maturity or experience apart from intelligence, are, of course, ruled out.) A criterion which Binet used is to locate a test at a specific age if about 75 per cent of the children at that age pass the test. Usually the per- centage fluctuates between 60 and 85 or 90 per cent. There are a number of distinct objections to this arbi- trary procedure, which have been pointed out by A. S. Otis 1 and T. L. Kelley.2 A test, however, is generally regarded as most useful which shows the most rapid advance with age, and which is placed in the year level at which about 75 per cent begin to pass. Although the writer recognizes the superiority of the 50 per cent criterion, nevertheless to make the results of our year- scale comparable with the Binet, we have continued the use of the 75 per cent criterion. To have used the 50 per cent criterion would have made the tests more difficult, because less age credit would have been assigned the successful completion of a design in the series. The procedure in the use of this performance scale is the same as that for the regular Binet, except that for those unable to speak or understand verbal directions, gestures and imitation are the means utilized to present the problem. It is necessary, therefore, that the trial design should be utilized before entering upon the exami- nation proper. For detailed instructions, however, the reader is referred to an earlier section (Part B, Chap. II, Section 2). 1 “ Some Logical Aspects of the Binet Scale,” Psychol. Rev., 1916, 23: 129-152, 165-179. 2 “ Further Logical Aspects of the Binet Scale,” Psychol. Rev., 1916, 23: 407-411. 80 INTELLIGENCE MEASUREMENT' 2. THE PERCENTILE METHOD Because of some important statistical fallacies under- lying this method as now utilized — fallacies which only one or two have as yet pointed out1 — we shall devote a rather extended discussion to this procedure. The developments in the field of differential psychology have doomed forever that much popular slogan: “We are all born free and equal.” The scientific study and analysis of individual differences has amply demonstrated that a given individual may rank first in one trait, last in another, and somewhere in between in another, and that this combination of ranks may be different for each individual. Thus in a group of one hundred, person A may rank ist in intelligence, ioth in motor coordination, 85th in general reaction time, 100th in height, and so on. Person B may rank 12th in intelligence, 57th in motor coordination, 3d in general reaction time, 7th in height, and so on. Person C may present an entirely different array of traits. This principle has been utilized by the Russian psychologist Rossolimo, for the measure- ment and the graphic representation of developed mental processes, which he designates the “ Psychological Profile Method.”2 1 See J. B. Miner: “Deficiency and Delinquency.” Warwick and York, 1918; 3SS pp. See esp. pp. 275-279. S. C. Kohs: “Percentile Norms for Scaling Data,” J. of Educ. Psychol., 1918, 9: 101-102. 2 G. Rossolimo: “Die psychologischen Profile. Zur Methodik der quantitativen Untersuchung der psychischen Vorgange in normalen und pathologischen Fallen. Eine experimentell-psychologische Skizze.” Klin, f. psych, u. nerv. Krankh., 1911, 6: 249-294. — English translation: B. STANDARDIZATION TECHNIQUE 81 Traits may be compared either for their quantitative or qualitative differences. At the present time we have developed a finer methodology for the former than for the latter. Thus our comparisons of one individual with another, or of one individual with a group, are largely comparisons of a quantitative nature. Theoretical Considerations: The percentile method or the percentile system is a method for determining or locating the rank or the posi- tion of an individual within a group. All the members of a group are ranked with respect to a given trait, the lowest member at one end and the highest member at the other. This arrangement is illustrated in Graph 6 A, and the curve therefor has been called the “ogive” by Galton. Assume, for purposes of illustration, that we are studying the heights of 58 four-year-old boys. We arrange these measures in increasing order, the lowest is 866 mm., and the highest is 1165 mm. (See Smedley’s Tables.) The curve connecting the separate heights of the 58 children is the ogive. Now if we run along the base from the 1st to the 6th case, the 6th case represents the 10th per cent case, and the height at this point is called the 10th percentile (964 mm.). Twice that dis- tance along the base brings us to the 12th case, and the height at this point is called the 20th percentile (968 mm.). And three times the original distance brings us Parker: “The Psychograph of Rossolimo,” Amer. J. of Insanity, 1916, 73: 273-293. See also Titchener Memorial Volume. For criticism see Ed. Claparede: “Profiles psychologiques gradues d’aprSs l’ordination des sujets.” Archives de Psychol., 1916, 16: 70-81. 82 INTELLIGENCE MEASUREMENT to case 17, the height at this point, 997 mm., representing the 30th percentile. And so on, for the 40th, 50th, to the 100th percentile. On the basis of this arrangement we may compare either two or more individuals for relative positions within the group, or we may compare the rank of one GRAPH 6A The Ogive Millimeters Heights of 58 four-year-old Boys arranged in order from lowest to highest. ( After Smedley.) in the light of the ranks of the other members of the group. With this orientation let us turn to the question of tests. The last five years have seen a rapid multiplica- tion of graded tests and scales, some intellectual, some pedagogical, some involving performance as distinct fom those tests involving the use of language symbols. With this growth has come the frequent suggestion that tests should be evaluated and interpreted in terms of STANDARDIZATION TECHNIQUE 83 percentile norms, and that we utilize the percentile method for grading and comparing individuals. In fact, four of the most extensive studies made within recent years, by Smedley, by Woolley and Fischer, by Doll, and by Pintner and Paterson, have made use of just this principle.1 In the last instance particularly, has the value of the percentile method been emphasized: “The percentile method seems to offer the best possi- bilities for future work. The percentile divisions used can be made as small as the delicacy of the tests will warrant. This method is especially desirable because it permits us to compare an individual’s performance with the performance of other individuals of the same age. It would seem at present, however, to require, for purpose of standardization, a very great number of un- selected individuals at each age.” (p. 212.) A fundamental fallacy, however, underlies the present practice in the construction and the use of percentiles. The quite recent report that the percentile method is 1 F. W. Smedley: “Report of the Department of Child-Study and Pedagogic Investigation. 1900-1901.” Child Study Report No. 3. Chicago Public Schools, 1902. H. T. Woolley and C. R. Fischer: “Mental and Physical Measure- ments of Working Children.” Psychol. Monogr., 1914, Vol. 18, No. 1. 247 p. H. T. Woolley: “A New Scale of Mental and Physical Measurements for Adolescents and Some of its Uses.” J. of Educ. Psychol., 1915, 6: 521-550. E. A. Doll: “Anthropometry as an Aid to Mental Diagnosis.” Re- search Publication No. 8, Vineland, N. J. Training School, Feb. 19x6. 91 p. R. Pintner and D. G. Paterson: “A Scale of Performance Tests.” New York, Appleton & Co., 19x7. 218 p. 84 INTELLIGENCE MEASUREMENT not meeting expectations cannot help but reinforce the writer’s opinion that the source of the trouble lies perhaps in the weaknesses of our present technique. “The corre- lation of the percentile method with the Yerkes-B ridges is the lowest of the four methods and at present does not seem of much value. Possibly this is due to the compara- tively small number of cases tested at each age.”1 Among the important cautions to be observed in scale- making are two: First, be certain of the zero point; second, be sure that the units of the scale are equal. This latter is of vital importance where scores of various tests in a scale are totaled or averaged, and then eval- uated in terms of percentile norms. All percentile differences should have a constant, not a variable connotation, and each percentile value should repre- sent a definite and constant position on the normal frequency curve. This is far from true with our present technique. Perhaps the chief and most destructive criticism of the present percentile method for scale construction is this: Equal percentile differences on the base of our orgive do not represent equal differences in ability between individuals. No one will argue that the amount of mental ability represented between percentiles io and o, equals that between 20 and 10, equals that between 30 and 20, equals that between 40 and 30, equals that between 50 and 40, and so on. In fact, we know from the psychology of individual differences that the differences in ability 1Pintner, R., and Reamer, Jeanette C.: “Children Tested by the Point Scale and the Performance Scale.” Psychol. Clinic, 19x7,11: 142- 151. p. 150. STANDARDIZATION TECHNIQUE 85 of adjacent cases among average, or mediocre, or most typical individuals is very small indeed, whereas the differences in ability of adjacent cases among extreme variates is, on the contrary, very great. For a clearer elucidation of this problem we must turn to the actual normal probability curve. The first clear explanation of the meaning and sig- nificance of the normal frequency curve came through the medium of an astronomer, Laplace — a mathema- tician, Gauss — and an anthropologist, Quetelet. The first two were engaged in efforts to determine the laws underlying the occurrence of purely accidental events, the last devoted a good part of his lifetime toward finding the “average man,” lost somewhere midst a confusion of diversity. (It might not be amiss to mention here that just in that realm where one would least expect the operation of fixed laws, the realm of chance and accident, we actually do find a clear-cut subserviency to funda- mental laws that definitely determine the frequency with which events occur.) If we should toss eight pennies (perfectly symmetrical) some few million times, then once out of every 256 times they would all come down heads; 8 times out of every 256 times they would come down 7 heads and 1 tail; 28 times out of 256 they would come down 6 heads and 2 tails; 56 out of 256, 5 heads and 3 tails; 70 out of 256, 4 heads and 4 tails; and once out of every 256 times they would all come down tails (theoretically). If we plotted these data as a column diagram we would obtain Graph 7. Or plotted as a smooth frequency curve we could graphi- cally represent the above facts as Graph 8. 86 INTELLIGENCE MEASUREMENT GRAPH 7 Theoretical Frequency 8 Pennies tossed 258 times Frequency No. of Heads GRAPH 8 Theoretical Frequency 8 Pennies Tossed 258 Times Frequency No. of Heads STANDARDIZATION TECHNIQUE 87 Laplace and also Gauss derived a formula for the theoretical normal probability curve which is given in Graph 9. GRAPH 9 The Normal Curve Sum of Ordinates: 125.3318 Curve Equation: Interval: 0.2 Units y=e~r Frequency (After Yule: ‘‘Theory of Statistics,” 1912. - See Table p. 303) Area: 10V or 25.06 + Units of Measure The probable occurrence of the different physical and mental traits possessed by human beings also distribute themselves, in many instances, in this bell-shaped fashion.1 Thus, in Graphs io, n, and 12, are represented 1 In this connection the writer wishes to call attention to an excellent article by E. G. Boring: “The Logic of the Normal Law of Error in Mental Measurement,” Amer. J. Psychol., 1920, 31: 1-33, dealing with 88 INTELLIGENCE MEASUREMENT the frequencies of the heights of fifteen-year-old girls, fifth-grade ability in arithmetic and the differences in the intellectual ability of 905 unselected children ex- amined with the Stanford-Binet Scale. GRAPH 10 Heights of 158 15-year-old Girls Frequency Centimeters (from figures by B.T. Baldwin, p.15, 'Physical Growth and School Progress”, 19U). For the purpose which we have set before ourselves at the beginning of this discussion, we cannot separate the normal probability curve from the ogive. Thus, for a given table of data, Table XXVII, Graph 13 is the ogive, and Graph 14 the frequency curve, both being plotted on the same coordinates. this particular matter, in which he points out the fallacy of a too general application of the “ normal curve ” to measurements of mental phenomena. STANDARDIZATION TECHNIQUE 89 GRAPH 11 No. of Addition Problems Solved by 687 Pupils in Grade 5 GRAPH 12 905 Children Intelligence Distribution Frequency Frequency Problems Quotients (from figures by C. Woody, “measurements of Some Achievements in Arithmetic,” 1916, p.27). {from figures by Terman: “Measurement of Intelligence," 1916, p.66). TABLE XXVII Starch Arithmetic Scale A * Scores in a 7th Grade Score s 6 7 8 9 IO II 12 X3 14 is | Total Frequency. . i 2 X s 9 6 S 2 I 2 1 I 35 ♦From Fig. 19, Starch: “Educational Psychology,” 1920, p. 35. 90 INTELLIGENCE MEASUREMENT In these diagrams items are numbered and their position on the ogive and on the column diagram may be clearly followed. It is of great importance to keep this relationship in mind, for in the confusion of the two curves lies the fallacy at the bottom of pretty nearly all the work in percentile scale making. Median: 8.9 Qi: 7.9 Q8: 10.5 Q: 2.6 Total Range: 3.8Q GRAPH 13 GRAPH 14 Arithmetic Score Arithmetic Score Frequency Cases in Consecutive Order In Graphs 13 and 14 the crosses on the base of the ogive represent equal percentile (decile) differences between measures. These may be followed through to the base of frequency curve. On the other hand, the arrows represent equal units, decile or percentile, on the base of the frequency curve, these then are referred back to STANDARDIZATION TECHNIQUE 91 ogive base. The marked lack of equality between the corresponding divisions is quite apparent. It should be emphasized that equal distances along the base of our ogive cannot, except under a combination of ex- tremely unusual circumstances, yield equal distances along the base of our frequency curve. But scale values must be equal if we are going to equate, add, subtract, multiply, divide, or compare percentile scores. It is equally true that equal units along the base of our frequency curve will not yield corresponding equal units on the base of our ogive. Another fact which requires mention is this: If we are going to determine the ability of a given individual, judged by reactions to more than one test, and utilizing the percentile method for determining his absolute score, then our percentile scale must be made up of score-values obtained from the base of our normal frequency curve, and not from the base of our ogive. The reason for this will be apparent from a study of the normal frequency distribution. It is evident that equal distances along the base of our normal curve represent equal differences in ability. This, unfortunately, is not true for the ogive. Consequently, if we take any percentile table in the current psychological or educational literature, ability represented by the difference between the ioth and 20th percentiles is far from equal to the ability represented by the difference between the 20th and 30th percentiles. But this would have been the case if the percentile scale had been laid off on the base of the normal frequency curve. These differences in ability represented by differ- ences in consecutive percentiles must be equal, if we are 92 INTELLIGENCE MEASUREMENT going to add, subtract, multiply, divide, equate, com- pare, percentile scores. To sum up the remarks above: Percentile scales should be so constructed that the various steps or units represent equal differences in ability. For devising a percantile scale, the normal frequency curve should be utilized and not the ogive as the base for operations. Practical Considerations In the following section will be indicated the wide divergence of percentile-scale values obtained by present methods, and percentile-scale values obtained by sug- gested methods. Example One Smedley, in Child-Study Report No. 3 (1902), Chicago Public Schools, gives the following data for Grip of Left Hand, Fourteen-year-old Boys (p. 17): TABLE XXVIII Percentiles IOO go 80 70 60 5° 40 30 20 IO O L. Hand Grip SI 36 32 30 28 26 25 23 21 19 14 This table is merely chosen as typical. Any other might have been taken in his report to illustrate the con- ditions. These percentiles were obtained in the following manner: “The individual cards on which the measurements were recorded when the child was tested were arranged according to the size of the pupils in each measurement, grouped separately for each age in years. The minimum STANDARDIZATION TECHNIQUE 93 measurement in each group gave the zero percentile for that group. To determine the ten percentile for that group, ten per cent of the number of cards was removed, beginning at the minimal end, and the highest measure- ment on the cards so removed was recorded as the desired ten percentile. Similarly the other percentiles were determined, the maximum measurement being recorded as the one hundred percentile.” (P. 13.) It is evident that the ogive rather than the normal frequency curve was used to determine percentile values. Since 359 cases were used by Smedley, it is a simple matter to reconstruct his initial table, which is here presented: TABLE XXVIIIA Left Hand Grip of 359 Boys No. or Cases L. Hand Grip No. OF Cases L. Hand Grip No. OF Cases L. Hand Grip No. OF Cases L. Hand Grip 3 14 22 24 9 34 2 44 4 IS 24 25 10 35 0 45 6 16 21 26 8 36 0 46 8 17 15 27 8 37 1 47 9 18 23 28 6 38 0 48 ii 19 19 29 7 39 0 49 16 20 16 30 5 40 0 5° IQ 21 17 31 2 4i I 51 25 22 12 32 0 42 20 23 IO 33 0 43 The point we have attempted to emphasize in this discussion is that in determining percentile differences among individuals, the curve of reference should be the frequency curve and not the ogive. The table given by Smedley is based on differences obtained from equal ogival distances. We herewith outline a procedure and present a table of percentile differences based on equal distances 94 INTELLIGENCE MEASUREMENT along the base line of the frequency curve, given in terms of standard deviation units or quartile deviation (P. E.) units. To find a score, then, corresponding to a given percentile, o, or io, or 20, and so on, it is merely neces- sary to determine the case which falls nearest that percentile, then by interpolation to obtain the refined score of the case. That value, then, is the score corres- ponding to the desired percentile. To illustrate: In the above example the range in score is from 14.17 to 51.50 (scores refined by interpolation), or a difference of 37.33 Kg. The percentiles then, in terms of this range, are as follows: TABLE XXIX Range Divided into Percentiles Percentile Range Value Percentile Range Value o 0.000 60 22.398 IO 3-733 70 26.131 20 7.466 80 29.864 30 11.199 90 33-597 40 I4-932 100 37-33° So 18.665 Now, adding these separate values to the initial score, 14.17, the final step in the formation of the percentile table is taken: TABLE XXX Percentile Score Percentile Score o 14.170 60 36.568 IO 17.903 70 40.301 20 21.636 80 44.034 30 2S-369 90 47-767 40 29.102 100 SI-SOO So 32.835 Score Values op Percentiles STANDARDIZATION TECHNIQUE 95 For purposes of comparison let us place in parallel position the two percentile tables, one obtained by the ogive method, the other by the frequency method, and then compare the scores. TABLE XXXI The Two Score Values Corresponding to the Same Percentile Compared Percentile Score Percentile Score Ogive Method Frequency Method Ogive Method Frequency Method o 14 14.170 60 28 36.568 IO 19 17.903 70 30 40.301 20 21 21.636 80 32 44.034 3° 23 25-369 90 36 47.767 40 25 29.102 100 Si 5i-5oo SO 26 32.835 Let us also note the cases which locate the various percentiles by the two methods: TABLE XXXII The Cases Which Locate the Percentile by the Two Methods Percentile Case Number Percentile Case Number Ogive Method Frequency Method Ogive Method Frequency Method o 1 I 60 215 324 IO 36 21 70 251 35° 20 72 70 80 287 356 30 X08 152 90 323 358 40 144 226 TOO 359 359 5° 180 289 96 INTELLIGENCE MEASUREMENT The significance of this new percentile table1 lies in the fact that the difference in ability between the first and 21st cases is equal to that between the 21st and 70th, the i52d and 226th, the 356th and 358th, or the 358th and 359th, and so on. By the ogive method percentiles are determined by grouping all of one’s cases into ten equally numbered groups. By the frequency method, however, the number of cases between percentiles is markedly unequal, thus in our table the number of cases between consecutive percentiles is 20, 49, 82, 74, 43, 35, 26, 6, 2, 1. These numbers mean that it takes 2 in- dividuals at one portion of the distribution to show as much difference in ability as is shown at other portions by 83, or at another by 20. To make the differences between the two methods more apparent, the following two figures (Graphs 15 1 In the above table for grips, the range in score is from 14.17 to 51.50, or 37-33- The arithmetic mean = 26.8 and the standard deviation is 6.46. Therefore, each unit of a = 5.78 units of the range • The total 0.40 range, then, from the o percentile to any other is equal to the sigma corresponding to that percentile multiplied by 5.78. Since sigma = 6.46, the sigmas corresponding to the different percentiles are TABLE XXXIII Sigmas Corresponding to Various Percentiles Percentile Percentile o . . . 0.000 60 . • 3-876 . IO . . . 0.646 70 . . • 4-522 . 20 . . . 1.292 80 . . . 5.168 3° . . . 1.938 90 . . . 5-814 40 . . . 2.584 100 . . . 6.460 50 . . . 3-230 The same, of course, would hold true for Quartile (P. E.) values. STANDARDIZATION TECHNIQUE 97 and 16) have been drawn to demonstrate first, the differences in score for each of the percentiles, and second, the differences in the positions of the individuals on the ogive who determine these percentile values. GRAPH 15 Score Difference between Two Methods Frequency Method More J Less Percentile Kilograms The block designs were not given percentile ratings, since it is an open question whether this method is an improvement either over the Year Scale Method or the P. E. Scale Method, both of which have been utilized in standardizing the block designs. In fact the per- centile method correctly used reduces this standardiza- 98 INTELLIGENCE MEASUREMENT tion method merely to a variation of the linear pro- jection method which is discussed later GRAPH 16 Case Locating Percentiles Ogive Method Frequency- Method Case Number 3. THE POINT SCALE METHOD A valuable discussion of this procedure (used by Yerkes, Bridges, and Hardwick) is found in Pintner and Paterson’s “A Scale of Performance Tests” to which we have had occasion to refer in some earlier sections. They very clearly point out its shortcomings. The allot- ment of points is absolutely arbitrary. There is no guid- ing principle, the method is purely haphazard, and the STANDARDIZATION TECHNIQUE 99 only check is the fear of making the mass of points cumbersome and unwieldy. Yet, that point scales are desirable is evidenced by the careful work of Otis {Jour, of Educ. Psychol., igi8). However, none of the point scales now in use are free from statistical and psychologi- cal objections which are inherent in the method and can only be removed by discarding entirely that method of standardization. 4. the p. e. scale method (Linear Projection Method) This method has been used extensively at Columbia under the direction of Thorndike, and we have adopted that methodology with some modifications to a stand- ardization of our block designs. The work of Bucking- ham in spelling, of Trabue with language scales, and of Woody with arithmetic scales, are examples. The chief advantage of this method of scaling tests is that each test in the series is given a definite weight depending on the successes or failures of children at each age. The normal probability curve is utilized in determining the location of a test on a P. E. Scale, the units of which are all equal. Each P. E. Scale has its zero point and each test is placed one above the other, depending upon the relative difficulty of each. By this means we have been able to project each design on a linear scale, each test being given a weight corresponding to its position on this scale. We were also interested in giving due weight to time and moves. For this purpose the times and moves for each design were correlated with life age. We found a most interesting situation, new to the standardization of mental tests. In correlating (a) suc- 100 INTELLIGENCE MEASUREMENT cess or failure in the designs, (b) time, and (c) moves, with age, we discovered that with age (a) yielded a correlation coefficient of about 80, (b) about 40, and (c) about 20! In other words, the respective weights for success, time, and moves are 4:2:1. Therefore, when we obtained the P. E weights for each design, time and moves were each given their respective weights depending on the initial value of the design. (See Chap. IV.) Our final standardization includes, therefore, a year scale such as the Binet, and a point scale derived by the P. E. scale method. The former may be supplemented by series of tests which others have standardized; the latter is a short scale complete in itself. A word in conclusion. Periodically, statisticians engaged in standardizing mental or pedagogical tests should take stock of their methods, technique, and fundamental assumptions. It is an attitude of mind well worth cultivating not to regard as final any set procedure by means of which scales are at present derived.. We are, unquestionably, inclined too frequently to forget that we are carrying over into education and psychology highly refined instruments which are of accepted service in biology, chemistry, and astronomy, but may not be utilized with the same degree of assurance and finesse in those sciences involving the human factor, such as sociology, psychology, and education. Well-merited criticism has already been launched against our blind utilization of correlation formulae and of transmutation tables, and our incessant worship of the “normal curve” fetish. STANDARDIZATION TECHNIQUE 101 In this chapter on standardization technique the writer is well aware of the many weaknesses in the methods for which preference is expressed. Until further progress is made, however, we must accept what we have with scientific caution, subjecting our procedures, at least, to the pragmatic test. CHAPTER IV The Standardization of the Block-Design Tests 1. Introduction 2. Age Standardization (a) Mental Age Norms (b) Sex Differences (Mental Age Norms) (c) Chronological Age Norms (d) Sex Differences (Chronological Age Norms) (e) Graphic Presentation of Norms (/) Final Year Scale 3. P. E. Standardization (a) Method (b) Time and Move Norms (c) Result: The P. E. Scale 4. Final Revision (a) Eliminations (b) Sex Differences (c) Final Norms I. INTRODUCTION The block-design tests used for standardization con- sisted of a series of twenty designs, graduated in difficulty (seepp. 66-67) and a set of sixteen specially colored cubes which were given to the S with the request to put the blocks, four, or nine, or sixteen, together and have the design on the tops of the blocks when complete resemble 102 BLOCK-DESIGN TESTS 103 the design as indicated on the card set before him. In this manner we had hoped to carry over into performance tests Ebbinghaus’s idea of a 11 Kombinations-methode” In this we were doing no pioneer work, having been pre- ceded by Healy, Knox, and Pintner, but this particular combination of method and apparatus is new. The cube material is described more in detail in Chapter II, Sec- tion i. Every one who has been given the test, from the young- est child to the adult, has manifested a keen interest in manipulating the material. There seems to be some fascination about performance tests in general which it would indeed be interesting to fathom. The directions which were given the S’s have already been stated in full elsewhere. (See Chapter II, Section 2.) A record was kept of success or failure, enough time being allowed for success if that seemed at all possible, and our final results show, in fact, that we were too lenient to the extent of anywhere from a half-minute to a minute in the case of each design. The final time limits have all been reduced as a result of our findings. The original time limits for the designs, upon which success or failure mentioned in the succeeding tables was based, were: Designs I-IX, minutes Designs X-XI, 3 minutes Designs XII-XVII, 4 minutes Designs XVUI-XIX, minutes Design XX 5 minutes Moves and time were both recorded, the latter in whole seconds. These two factors, however, did not here affect the score: “passed” or ‘Tailed.” For an explana- 104 INTELLIGENCE MEASUREMENT tion of what was considered a move, see previous section on directions for applying the tests. In the final standardization by the linear projection method three designs, XI, XIII, and XVII, were omitted and the others were assigned the following Arabic num- erals : Design I now Design i Design IX now Design 7 ii ii ii ii 2 ii X a ii IO a hi ii ii 3 a XII a ii ii a IV ii ii 4 a XIV a a 14 a V ii ii 5 a XV a a 12 a VI ii ii 6 a XVI a a 13 a VII ii a 9 a XVIII a a 15 a VIII ii a 8 a XIX a a l6 Design XX now Design 17 2. AGE STANDARDIZATION We shall utilize both chronological and mental age standards in assigning age values to each of the designs. Some may object to the use of mental ages for standard- ization, but we have found no valid reasons for rejecting this criterion; in fact there are obvious reasons for its utilization. First, it serves as a check on an impartial selection of children — if they happen to be somewhat retarded or accelerated, the mental age difference will weight the norms accordingly. Secondly, we wish to translate our norms in terms of Binet mental age, so that a mental age obtained by this performance scale will possess the same significance as a Binet mental age. Nevertheless, Pintner and Paterson1 maintain “Why should we know the mentality of the children we are 1 “A Scale of Performance Tests,” p. x O O O co co n o O' h g g co 'O O O M M XVI o o o oo oncoO'O o M CO IO N lo O O M M > O O O *o *o co O Tf-vo N Q Q M CN M tJ- co *0 O O M M XIV OOOLO'tr^O^t-^wOO H tJ- CM vO rj- io O H I IIIX O O O OO ro K o !*) tN n O Q H « co *0 CO 00 o M XII m cn co 0 O M M X OOOOOOOOOvOmOnOO CO *0 CN VO *0 X OOOoOMt^OcoOt^OO co cn vo co *0 *0 VO O M a OTj-OMOt^OgvOr-OO W M CO LOVO oo O co *o O O M M M vm o O co O OwO o o CN CN Tt"0 00 *000 O M vn O CO O O Q CN CO Tt" *0 rtco O > OwO o q cn co *0*0 O 0 M M > O o O' ro N o OwO vo O O m covO 00 OvOO 00 OO O O M M & O M o vo *0 co O Ovvo vo O O CN oo rt 00 00 00 O O M M E O C- O *000 NO O too O O iovo 00 00 00 Ov 0 OvO O O M M M M « *ooo Ng g tog o o VO 00 00 00 00 O 0 OvO o 0 W M M M M - COVO OQQQQQOOOO co 00 OOOOOOOOOOO WWHMHMMMW No. of Cases COVO *o O Qv Th vo CN M M M M M M HH Life Age vO O' O h CJ co’t *OVO t>» MMHHMWMM Chronological Age Norms (at or within i Yr. of Grade) Per Cent Passing (Boys) TABLE XLIII BLOCK-DESIGN TESTS 123 No. op Design Number Age Cases I II III IV V VI VII VIII IX X XI XII xm XIV XV XVI xvn xvm XIX XX 6 9 56 33 44 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 7 12 75 33 42 25 0 8 0 8 8 0 0 0 0 0 0 0 0 0 0 0 8 18 100 72 72 49 33 22 17 22 28 6 6 0 0 0 0 0 0 0 0 0 9 ii 9i 73 73 27 27 27 9 18 27 9 18 0 9 9 9 9 9 9 0 0 IO 12 100 92 67 75 75 67 8 42 25 17 O 17 8 8 8 8 8 8 0 0 ii IO 100 90 90 80 80 70 5° 5° 70 IO 40 60 0 no 30 30 5° 10 0 0 12 12 100 100 100 92 83 92 33 58 67 17 58 58 33 17 25 42 58 33 17 8 13 13 100 92 85 92 77 69 39 69 69 3i 3i 39 15 39 23 39 49 39 15 23 14 9 100 100 '1OO 89 89 89 67 89 78 59 22 59 44 33 44 44 44 44 33 22 IS 8 100 88 100 100 75 88 63 75 75 63 5° 63 5° 50 38 5° 5° 5° 25 25 16 6 100 100 100 100 100 100 50 93 100 50 50 67 5° 67 97 50 97 97 33 17 Chronological Age Norms (at or within i Yr. of Grade) TABLE XLIV Per Cent Passing (Girls) 124 INTELLIGENCE MEASUREMENT Life No. OF Design Number Age Cases I II in IV V VI vn vni IX X XI xn XIII XIV XV XVI xvn xvm XDC XX 6 15 47 20 27 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 7 26 81 50 5° 23 4 4 4 8 12 0 0 4 0 0 0 0 0 0 0 0 8 28 93 75 68 36 25 21 18 21 21 4 4 4 0 0 0 0 0 0 0 0 9 24 96 79 79 38 33 29 4 21 29 8 13 13 8 13 13 8 8 8 4 0 IO 28 100 89 79 75 68 57 25 43 39 25 21 25 11 29 18 14 25 11 4 0 ii 25 100 88 88 76 84 68 44 60 68 20 40 48 16 24 20 32 48 16 4 4 12 22 100 100 96 86 86 82 41 64 73 36 5° 64 18 36 32 41 59 23 23 9 13 22 100 96 9i 9i 82 68 41 77 82 32 41 41 23 41 32 46 46 32 14 14 14 23 100 96 96 87 87 83 61 87 83 52 52 70 52 48 39 61 6S 52 44 30 15 15 100 93 100 93 80 87 53 67 67 60 40 67 53 60 47 53 60 53 33 33 16 11 100 100 100 100 100 100 64 82 100 55 55 82 64 64 82 73 82 82 36 46 17 2 100 100 100 100 100 100 100 100 100 100 50 IOO IOO IOO IOO IOO IOO IOO IOO IOO Chronological Age Norms (at or within i Yr. of Grade) Per Cent Passing {Total) TABLE XLV BLOCK-DESIGN TESTS 125 (d) Sex Differences {Chronological Age Norms) Table XLVI analyzes the sex differences in the differ- ent age groups for the first ten designs, for the last ten, and for the total. TABLE XLVI Sex Differences Design No. Chronological Age Total 6-8 9-13 14-17 I-X XI-XX I-X XI-XX I-X XI-XX I-X XI-XX Number of instances boys superior . Per cent 00 -00 vO CN \0 w VO 00 00 VO M m o M MMMMMMMM XVI m O co CN OOO CO O' CN O' Tf rf O' VO CN lO CN M > CN M O' O00 O O VO O' M O' 0"0 lO'O -<3- CO CO CN M a Os CN O' CN Tt-00 CO CN co co cn co cn m a O' O t*- cn CO V) lO CO O'VO Tt- O' lo N Tt CO Tf Cl CN CN M CN M a CO CN OO OO CN VO N M VO 00 00 *0 N N co CO CO CN CN CN M M M - CN Tt- Tf rt CN 10»00 C^COCOCNCNCNCNMMMM Life Age vO O' O M CN co rf IOVO MMMMMMMM Time Norms (Seconds) TABLE LVIII BLOCK-DESIGN TESTS 149 o V)fO OOO V0 lo X 4 rfCO CO CS W COM CO W W v O O O X Tf co d 6 oo w oo o CO CO N CO CM CO W cow a m o m u) ion Tf o 5 ci O 6 Tj* 6 cocococow W W W W M O O O N W)W)N «) O £ ci w 4 d d con w cocococow W cow ONNOOO»0>ON.O X W o d VO O O NOO N cococow COCOW Cl Cl COCO N> M O N" r$* lo X lorfdw C>» C>* M d M cocow cow ci cow CO O cc COOO « O 00 O' o a X t>*vo cocod MMCICIMMMMM O O co O m co co co *0 X N HO0 O O TfvO M CICIMMMMMMMMM o ioNaa 'too o n o § X n* do cd co oo n O CIMMMMMMMMM O O rj* w O' m tt CO O O w p X d d d 4 o tj-woo 6 d mwmcncicicimcim a co O O rj- N o N> N- M Cl lo C-. 4 *-0 W O' O' N O' N N Tj- M M M M M M O' H Tj- O N M V) a > o vo oo o co oo 0 m MM M M O w o VO N- rj-vO CO rf W o > i>» -4- loco ci cd lo cd cd w d MM MMMMMMM O Ifl O t 1000 ti HO & o > cdcoMCiciowoO cooo N» MMMMMMM M O N. O' nt O' O' O COOO O lo > id cd m o w d ooo d O' 4 M M M M M -t LO CN NION VO CO N tO & o ci ci M 00 00 00 0 N M M M M _ CO N- CO W co 1C N o w M co O cd d d-vd dvo x>* vd o cd to to 0"0 N O N NOOOO o a M dvo Lovd lovO rf LO LO M 0 o vo q>vo q co o cd LoLOLOLd'd-LOTt-'d-'d-d'Tf 34 VO N* CO Qn o m w CO rf N* MMMMMMMM Move Norms (Moves) TABLE LEX 150 INTELLIGENCE MEASUREMENT at age 17. So, too, for moves. For Design I, at age 6, 8.9 moves are made before success is finally accom- plished, as compared with 5.6 moves at age 10, and with 4.6 moves at age 14. And again, for Design XIX, at age 9,42.0 moves (almost 3 moves to each block) are made before the design is successfully completed, as compared with 28.9 moves at age 14, and only 21 moves at age 17. An analysis of sex differences reveals the following: For designs I-X, ages 6-8, the tendency is greater for boys to give longer times on the same designs, although the frequency for giving long reaction times is about the same for both groups. For designs I-X, ages 9-13, boys more frequently exceed the times of the girls (ratio: boys, 31; girls, 18), but the amount of ex- cess is about the same (ratio: boys, 15"; girls, 18"). For designs I-X, ages 14-16, and for designs XI-XX, ages 9-13, no tendency is evident for boys to exceed girls in time per design, or vice versa, the excess being about the same. And in designs XI-XX, ages 14-16, boys more frequently give longer times (ratio: boys, 24; girls, 6), but the girls give longer times whenever they exceed in time (ratio: boys, 27"; girls, 34")- In general, it may be stated that boys tend to give longer reaction times more frequently than girls, but when girls take longer the excess in time is greater than the excess in time for boys. As regards sex differences in moves, there are no ap- preciable differences except for designs I-IX at ages 6-8, and 9-13. In the first instance, the tendency to make a greater number of moves is about the same, but the excess is greater for boys than for girls; and in the latter BLOCK-DESIGN TESTS 151 case, the tendency to make a greater number of moves is stronger for boys than for girls, but the excess of moves is about the same. Tables LX, LXI, and LXII give the correlations be- tween time and moves for the four-block, nine-block, and sixteen-block designs. The correlations are high, as one would expect. TABLE LX Correlation between Time and Moves Moves Time Total 1'-3°' 31 i'i'-i'3o' 1'31 '-2' 2'l *-2'30’ 4 . . . 140 IO 1 151 5- 8 . . . 192 90 8 3 I 294 9-12 . 13 IO 27 6 4 60 13-16 . . . 3 18 11 7 39 17-20 . . . IO 8 6 24 21-24 . . . 6 2 7 15 25-28 . . . 1 1 2 29-32 . . . 1 1 2 4 33 and over . 1 1 Total 345 113 7i 32 29 590 (4-block designs) r = + .76, ± .01 Four groups of workers may be segregated from these figures by horizontal and vertical divisions of the tables. One group which works rapidly and accurately, and con- sists almost entirely of those who succeed. A second gi'oup which works somewhat too rapidly perhaps, and attempts numerous varieties of block-combination. A third group which works slowly, makes few moves and appears deliberative in procedure. And a fourth group which not only works slowly, but also attempts numerous combinations, many bordering on the irrational. 152 INTELLIGENCE MEASUREMENT TABLE LXI Correlation between Time and Moves Moves Time Total I -30 i'i 2'l'-2'3o" 2'3l'-3' 3'l'-3'3°' 3'3l'-4' 9 4 I 5 10-15 I 4 9 9 2 2 27 16-21 2 10 12 12 7 43 22-27 I 3 3 6 4 2 19 28-33 I 4 I I 7 34-39 1 I 40-45 I 1 Total I 10 21 24 18 20 5 4 103 (9-block designs) r = + .58, ± .04 Correlation between Time and Moves TABLE LXII (16-block designs) Moves Time Total 31’-1' l'3l ’-2' 2'l'-2'30' 2'3I '-3' 3'i'-3'3°’ 3'3l'-4' 4'i'-4'30* 17-20 3 I I I 6 21-24 1 13 IO 6 2 32 25-28 1 II 9 II 2 34 29-32 2 7 6 7 I 23 33-36 3 8 8 4 23 37-40 2 5 2 3 I 13 41-44 2 3 2 I 8 45-48 1 3 I 5 49-52 53-56 1 I 2 Total I 17 24 28 36 20 16 4 146 r = + .70, ± .03 BLOCK-DESIGN TESTS 153 (c) Result: The P. E. Scale On the basis of these results bearing upon the relation between time and moves, and in view of the earlier find- ings, the following score-card was devised (Table LXIII). The attempt was made to apportion due weight to (a) score value, (h) time, and (c) moves in the ratio of about 4: 2: i. TABLE LXIII Score Card Design P.E. Score Excess Time Excess Moves Number Value Deduct i Point Deduct 2 Points Deduct i Point I II III 3 5 6 21" and over 31" and over 21"- 35" 36" and over 6 and over 7 and over 8 and over IV 7 31 "-i' 1' 1 "and over 10 and over V 7 36r-i' 5" 1' 6" and over 11 and over VI 7 36r-i* 1' 1" and over 12 and over VII 9 56"-i'io" i'ii" and over 15 and over VIII 8 4i"- 55" 56" and over 10 and over IX 7 4i"-i'io" i'ii" and over 11 and over X 9 i/56"-2,io" 2'n" and over 22 and over XI 9 i'36"-2' 2' 1" and over 18 and over XII 8 i'46*,-2,3o" 2'31" and over 19 and over XIII 9 i'3i'-2'3o' 2'3i" and over 18 and over XIV 9 2'26"-2'4o" 2'41" and over 32 and over XV 9 2'26"-2'40" 2'41" and over 30 and over XVI 9 2 21 -2 33 and over 31 and over XVII 8 i,56<'-2,25‘' 2'26" and over 30 and over XVIII 9 2'4I '-3' 0" 3' 1" and over 32 and over XIX IO 2'4i"-3' 5" 3' 6" and over 31 and over XX ii 2,4i*’-2'sstf 2'56" and over 30 and over Maximum Score = 159 Points The information in the last three columns of the pre- ceding table was obtained by plotting first the norm data for each design at each age, both for time and for moves. All the curves were then smoothed. After that the year-range of the curve was divided into as nearly 154 INTELLIGENCE MEASUREMENT three equal year-divisions as possible. Thus for design XI the total year-range for the time-and-life-age curve was nine years (age 8 to age 17). All times, then, falling within the range of years between 14 and 17 were allowed as legitimate. One point of the score value of the design, however, was to be deducted if the time taken fell within the range of years from n to 14, and two points were to be deducted if the time taken fell within the earliest range of years, namely, between the years 8 and n. The same procedure was utilized for determining the deductions for excess time on the other designs, except designs I and II for which the method pursued for moves was followed. For the one point deduction for excess moves the year-range was divided into two parts. The range of moves covering the higher half of years was regarded as legitimate, whereas the range of moves covered by the lower half of years was regarded in excess and one point was designated as a reasonable deduction from the score value of that design. Other methods for arriving at an objective criterion for making subtractions for excess time and moves were possible.1 For example, instead of the year-range being divided into three equal divisions, the score-range might have been thus divided. Another method possible would have been to take the score-range and divide it into four equal parts. Two points would then be de- 1 It did not seem that any other possible methods possessed any superior value over the one actually utilized, and in any event, what- ever the procedure for penalizing excess moves and time, the chances are very great that no great differences would have resulted in the ultimate score assignments to each performance of the block-design tests, and in the final standards. BLOCK-DESIGN TESTS 155 ducted for the first quarter of the range falling at the lowest ages, one point would then be deducted from the middle range of 50 per cent, and all times falling within the upper range of 25 per cent would have been regarded as legitimate. Utilizing the scoring instrument thus devised, all the tests were then re-scored. The original correlation be- tween the Binet Scale and the number of designs suc- cessfully completed (already designated as the “raw score,” time and moves not being taken into account), was + .82, ± .01. The table is presented herewith: TABLE LXIV Correlation between Binet Mental Age and Raw Block-design Scores Bind Age Raw Scores 3 4 s 6 7 8 9 IO II 12 13 14 is l6 17 18 19 Total o 3 7 14 14 3 1 1 43 I 7 9 9 2 2 1 1 I 32 2 5 5 7 7 3 3 30 3 4 6 6 5 1 1 2 1 26 4 i 7 6 S 2 1 I 1 24 S I 3 9 6 5 1 1 1 27 6 i 5 4 4 4 3 2 I 24 7 4 6 6 3 1 I 21 8 2 3 3 1 1 1 11 9 i 1 2 4 I 1 2 12 IO 1 3 3 3 I 11 ii 4 4 1 1 10 12 1 1 2 1 1 I 1 8 13 1 4 2 2 1 10 14 2 4 1 5 1 1 14 IS 1 I 4 1 2 1 10 16 1 2 4 I 1 9 17 1 3 I 2 1 I 1 1 11 18 1 1 3 1 3 2 11 19 2 2 1 2 1 1 2 11 20 1 1 3 3 1 2 11 Total . . 3 7 14 3i 29 Si 37 44 44 3i 20 17 11 11 7 4 5 366 156 INTELLIGENCE MEASUREMENT Although some of the values in the preceding table are scattered, there is a marked consistency in the in- crease of raw score with increase of mental age. Upon rescoring the 366 tests in order to assign due weight to success, time, and moves, the coefficient of correlation is not changed to any appreciable amount, but there is a marked decrease in the fluctuation, or spread, of scores over any given range of years. This is more apparent after the elimination of certain designs, discussed more in detail in the succeeding section of the monograph. The correlation table follows: TABLE LXV Correlation between Binet Mental Age and Score Points Score Points Mental Age 3 4 s 6 7 8 9 IO II 12 13 14 is l6 17 18 19 Total o . 3 7 14 14 3 I 1 43 I-IO . 15 19 20 12 6 5 1 1 1 80 II- 20 2 3 13 11 9 2 2 4 1 47 21- 30 3 9 7 7 5 4 3 2 40 31- 40 7 2 4 6 3 1 2 3 41- 50 1 1 1 4 S 1 1 1 IS 51- 60 4 6 4 3 1 1 19 61- 70 2 3 2 1 I 1 1 1 12 71- 80 4 3 1 1 9 81- 90 2 2 2 3 1 2 12 91-100 3 2 S 3 1 2 16 101-110 1 3 2 2 8 111-120 1 1 1 2 1 2 8 I21-130 1 3 1 1 1 2 9 131-140 2 2 1 2 2 2 11 141-150 1 2 1 2 1 7 ISI-160 3 2 1 1 7 Total . 3 7 14 31 29 Si 37 44 44 3i 20 17 11 11 7 4 5 366 f — + -83, ± .01 BLOCK-DESIGN TESTS 157 In order to appreciate the significance of this coeffcient, the following list of correlations between the Stanford- Binet test and other intelligence tests is presented: Block-design Test and Binet Test . . + .83 Army Alpha and Binet Test,1 . + .80 to + .90 Army Beta and Binet Test,1 . . . + .73 Stanford-Binet and Stanford-Binet (repeated tests),1 -j- .94 to + .97 Stanford-Binet Entire and Stanford-Binet Abbreviated (2 tests per year)1 + .92 Each Army Performance Test and Stanford-Binet1: 1. Ship Test 2. Manikin and Feature Profile Test 3. Cube Imitation Test 4. Cube Construction Test 5. Form Board Test 6. Reproducing Designs Test 7. Digit-Symbol Test 8. Maze Test 9. Picture Arrangement Test 10. Picture Completion Test Lowest Correlation, +.48 Highest Correlation, +-78 Abbreviated Army Performance Test (5 Tests) and Stanford Binet,1 + -84 Stanford-Binet and Seguin Form Board,2 . . -f- .55 Porteus and Stanford-Binet2 Boys . . . + .21 Girls . . . + .60 Healy’s 3 Form Boards (Mare and Foal, Construction Test A, and Construction Test B) and Stanford-Binet Mental Age,3 . + .45 Porteus Mental Age and Stanford-Binet Mental Age 3 . . . + .79 Army Alpha Teachers Estimate Class Standing and Ferguson Form Boards4 + .5i + -So + .56 Grade Location and Form Board Ability,4 + .80 1 C. S. Yoakum and R. M. Yerkes:“ Army Mental Tests” (New York, Holt, 1920), p. 20 * S. D. Porteus: “Porteus Tests—The Vineland Revision” (Vineland, 1919), p. 28. 19, 20. ’Elizabeth L. S. Ross: “Vocational Tests for Mental Defectives: Studies in Mental Inefficiency” (1921), 2: i-t>. * G. O. Ferguson, Jr.: “A Series of Form Boards,” J. of Exp. Psychol., 1920, 3: p. 37- 158 INTELLIGENCE MEASUREMENT Inter-Test Correlations 1 TABLE LXVI (Table Rearranged) Army Thurstone Pressey Indiana Survey Otis Army + .60 + .36 + .36 + •57 Thurstone + .60 + .25 + -25 + 46 Pressey .... + -36 + -25 + .22 + -44 Indiana Survey . + -36 + .25 + .22 + -34 Otis + -57 -f- .46 + -44 + -34 Pintner’s Non-Language Group-Test and Stanford-Binet I. Q.,2 -f .66. A cursory survey of the stragglers in the upper right- hand corner of the table (LXV) reveals children who ob- tain high Binet scores, but do poorly in these tests. These are generally children who are retarded mentally or are feeble-minded. There seems to be evidence that children of inferior endowment do poorer work with these tests than children of superior endowment but of the same mental age. So, too, the stragglers at the lower left-hand corner of the table are children who are foreign born, the language-handicapped, such as the Portuguese, Italians, Japanese, and Chinese, who do poorly with the Binet, yet obtain good scores on the designs. The following are the median scores at each mental age. These medians were determined from a table of 1 J. A. Clement: “ Use of Mental Tests as a Supplementary Method for Making School Adjustments in Colleges.” Educ. Adminislr. and Superv., 1920, 6: p. 441. 2 R. Pintner: “A Non-Language Group Intelligence Scale. ” /. of Applied Psychol 1919, 3: 199-214, p. 214. BLOCK-DESIGN TESTS 159 original data, no grouping of scores beyond the one unit being made for scores 1 to 15. Beginning with score 16, however, the frequency intervals were 5 score-points. The median values in Table LXVII are, therefore, inter- polated only from age ten up. The left half of the table presents actual values, and the right-hand portion the medians obtained from the smooth curve of Graph 42. TABLE LXVII Actual Medians Smooth Curve Medians Age Score Points Age Score Points 3, 4, 5 o 3> 4i S • • • • 0 6 ' i 6 I 7 5 7 S 8 IS 8 9 9 13 9 17 IO 29 10 29 ii 48 11 4i 12 63 12 ss 13 S3 13 71 14 92 14 88 is 118 is 104 16 114 16 118 17 143 17 133 18 138 18 143 19 132 19 152 20 159 20 159 Median Scores at Each Mental Age Graph 42 is the curve showing the increase of score with mental age. The dots represent the median scores at each age. The deviations between the curve and the actual medians are explained largely on the basis of idiosyncracies in the age-groups tested. Thus at age thirteen, the difference is quite striking. But by referring 160 INTELLIGENCE MEASUREMENT back to the table showing the correlation between Binet age and life age (Table XIII) it will be observed that at thirteen the median mental age of the group examined (33 —16 boys and 17 girls) was about twelve years, a -GRAPH—42- J n c rea se_of_Sco re_Po i n ts_wi th_ Age. Block - design Score Points Binet Mental Age retardation of approximately one year. Referring back to the curve (Graph 42) for the performance of the 12- year-mental-age group, it will be observed that this group attains scores superior, on the average, to the 12-year standard, but inferior to the 13-year standard. The explanation is practically the same for the deviations at the other ages. BLOCK-DESIGN TESTS 161 There was a twofold motive in further work to make the block designs a reliable and a serviceable test: In the first place, it was deemed wise to reduce the time for giving the test as much as possible without a sacrifice of reliability; and, on the other hand, there were a few designs which, if eliminated, would tend to decrease the scatter of scores over a given range of mental ages. It was for these reasons that further analyses were made, in order to determine which designs could be sacrificed in order to bring the above desirable conditions to pass. Space prohibits an extended discussion of the technique of elimination, but the main features of the revision are presented in the following section. 4- FINAL REVISION (a) Eliminations In reducing the number of designs it was recognized that the most desirable procedure to follow would be that which would result in the greatest reduction of scores for those of progressively poorer mental capacities, without affecting the scores of those of higher mental development. A general leveling of scores, without a compensating increase in the diagnostic importance of a unit score, as a rule, decreases the actual diagnostic value of any measuring scheme. The designs, therefore, which were considered for elimination were those falling within the middle range, namely, designs VII, XI, XIII, XIV, XV, XVI, and XVII. On the basis of various criteria which were utilized, those designs could more easily be sacrificed than the others. 162 INTELLIGENCE MEASUREMENT Three elimination schemes were tried: (а) the elimination of designs VII, XI, XIII, XVI, and XVII; (б) the elimination of designs XI, XIII, XIV, XV, and XVII; and (c) the elimination of designs XI, XIII, and XVII. The final eliminations to be effected were to be those which would (a) most effectively reduce the scatter or range of scores from ages 3 to 19, (b) that would save time with least sacrifice of diagnostic efficiency, (c) that would result in a higher coefficient of correlation between block-design score and Binet mental age, and (d) one that would show an increased reliability of final score achieved. Elimination Method (a). Thus elimination method (a) permitted a maximum score attainment of 115. The correlation beween the number of points lost (from the original score using the twenty designs) and Binet age was + .63 d The number of cases in which the score was affected was 140 or 38 per cent. Analyzing the results of this re-scoring method more closely, it becomes apparent that taking each mental age there has been a greater ratio of reduction in the scores of the lower ages (73 per cent) and a smaller ratio of reduction in the scores of the upper ages (27 per cent) — although the absolute values show a gradual increase in points lost with increase of age. The changed scores make for a 1 This coefficient may also be interpreted as the correlation between these five designs taken alone and Binet mental age. This is a fair criterion of the reliability of the block-design tests as a whole, if thes,. five designs are the poorest. BLOCK-DESIGN TESTS 163 greater differentiation between the lower and the higher mental ages. Although the extremes of score were from 5 to 159, the latter score being 31 times the former, the extremes of per cent lost were from 8 to 41, only 5 times the former instead of 31. Elimination Method (b). Rescoring the tests on the basis of the eliminations by method (b) the maximum score attainable is 115, the same as by method (a). Here again the correlation between block-design scores and Binet mental age was -f .85 ± .01. In this instance, however, the scores at the lower ages were affected to the same extent as by method (a), but the scores at the higher ages were reduced in greater proportion than was the case with method (a), largely due to the limitation of designs eliminated to those above design X. Com- paring the two methods, it was found that in 46 per cent of the cases, method (a) yielded higher scores than method (b), in 24 per cent of the cases method (b) yielded higher scores than method (a), and in 30 per cent of the cases, the scores by both methods were exactly the same. Elimination Method (c). Based on the results of methods (a) and (b), method (c) is a compromise, only those designs being cast for elimination which were common to methods (a) and (b). By this method the maximum score attainable is 133, 26 less than when all the twenty designs are used. The correlation between block-design score points and Binet mental age is .84 ± .01. A survey of the correlation table (Table LXVIII) reveals a somewhat greater consolidation, or a reduction in the scatter, of the tabulated scores about the mean trend as compared with the original correlation table 164 INTELLIGENCE MEASUREMENT (Table LXV) which presents the scores based upon the use of the total twenty designs. TABLE LXVIII Correlation between Binet Mental Age and Score Points (Elimination Method (c)) Binet Mental Age Score Points 3 4 s 6 7 8 9 IO II 12 13 14 IS l6 17 18 19 Total o 3 7 14 14 3 I 1 43 I- IO IS 19 20 12 6 S 1 1 1 80 II- 20 2 3 13 11 9 2 2 4 1 47 21- 30 3 IO 7 9 s 4 3 2 43 31- 40 6 2 3 7 4 1 23 41- 5° 1 1 1 6 9 3 3 2 26 SI- 60 1 4 5 3 I I I 16 61- 70 1 1 3 4 3 1 I 1 15 71- 80 2 2 2 5 3 2 16 0 O' \ M 00 1 3 2 4 I 11 91-100 1 3 2 I 1 2 10 101-110 1 2 1 2 3 3 3 3 18 111-120 1 I 2 1 1 1 7 121-130 1 1 3 2 1 8 131 and over 1 1 1 3 Total . 3 7 14 31 29 Si 37 44 44 3i 20 17 11 11 7 4 S 366 r = + .84 ± .01 A comparison of the mental ratings resulting from this new array of designs with those in which all the designs were included, and with those in which elimina- tions (a) and (b) were made, revealed that the original determination of reducing the scatter of scores, of saving time without a sacrifice of diagnostic efficiency, of in- creasing jthe validity of the final score achieved, and of increasing the correlation between block-design scores and Binet mental age, had, to a degree been accom- BLOCK-DESIGN TESTS 165 plished. The superiority of elimination method (c) is again made manifest from the following table, which shows what per cent the quartile deviation is of the maximum score (the score-range) at each age, for each of the elimination methods. TABLE LXIX Per Cent that Q. D. is of Score Range Age 6 7 8 9 IO II 12 13 14 IS 16 17 18 19 No designs eliminated . 2 2 6 6 14 IS 19 25 16 24 17 6 5 6 Elimination Method (a) 3 3 8 9 14 IS 16 3i IS 22 21 7 7 8 Elimination Method (b) 3 3 8 8 14 13 16 22 13 25 24 8 8 9 Elimination Method (c) 3 3 7 7 13 13 i7 22 15 22 20 9 9 8 b a b a a Method Preferred any any c c c or or or b or c a a or f 6 c c c The directions for the block-design test, the methods of scoring, and the norms, to which Chapter II of Part B has been exclusively devoted, are based upon the results obtained after rescoring the test blanks, designs XI, XIII, and XVII being eliminated. The designs, after this final revision, have been renumbered as already explained in the introduction to this chapter, each de- sign now being designated by an Arabic instead of a Roman numeral. (b) Sex Differences On the basis of the changes in scoring above indicated, a second analysis was made to determine sex differences. 166 INTELLIGENCE MEASUREMENT This attempt was not as thorough or as complete as the first, indications very early pointing toward no change in the original findings. There was no reason to expect any shifts in the comparative performances of the sexes, since all efforts with the designs were in the direction of refining the test procedure and of improving the method for placing a specific intelligence-valuation upon any given response. The block-design test as it now stands is comparatively free from the disturbing factor of sex for the first ten designs and for ages below thirteen or fourteen. For the last seven designs and for ages above thirteen, boys seem slightly superior to girls. The reason for this dif- ference at the upper ages and for the more difficult designs is not immediately apparent. Attention has already been directed toward reasonable explanations. (See pp. 118-121, and pp. 125-126.) Possibly introspective evidence might throw consid- erable light upon the matter. At any rate, the differences between the sexes are not so great as to invalidate the results which one might obtain, nor is a compensating formula necessary to correct any error which might be theoretically assumed. For all practical purposes sex differences may be disregarded. (c) Final Norms The final norms, with a suggested procedure for giving and scoring the block-design tests are presented com- pletely in Chapter II (Part B). The writer has assembled all of this material in one chapter, in order to facilitate the use of the designs and to assist the interpretation of BLOCK-DESIGN TESTS 167 results derived therefrom. The longer one uses the block design tests, the more is one convinced of the superiority of the P. E. method of scoring and interpretation over the year-scale method. By means of the former, finer gradations are possible, resulting in finer intelligence differentiations. It is therefore recommended that the P. E. method be used in preference to the year-scale method. CHAPTER V The Results I. DO THE BLOCK DESIGNS MEASURE INTELLIGENCE? To answer this question, one must necessarily first define intelligence. Perhaps the easiest way out of the difficulty is to state that this test measures very largely the same kind of mental processes that are measured by the Binet scale. And if the Binet scale measures intelli- gence, so do the block designs, as is evident from the high correlation between the two. To some, this reply may appear an evasion of the issue and quite unsatisfactory. In that case we must review the current definitions of intelligence. These fall prac- tically into two types, (a) those expressed by Ebbinghaus, Ziehen, and Meumann, and (b) those expressed by Binet, Stern, and Terman. According to the first group, “Intelligenz ist Kombinationsgabe”— intelligence is the ability to “put two and two together,” the ability to combine, to synthesize. Whenever, for purposes of adaptation or problem solution, we are called upon to bind together, or to relate, two or more experiences which have, in our own lives, never before been tied up, we are utilizing “intelligence” factors in the process. The more efficient this combination in actual practice, or the less open it is to error and misdirection, the more effective has been the functioning of this “intelligence 168 THE RESULTS 169 machinery.” There is no question but that “intelli- gence” is dependent upon a large mass of materials which have been acquired through experience and stored away ready to be called upon whenever occasion demands its use, but “intelligence” as such is neither “experience” nor “information” but “combinative power” — the ability typified, for example, in the mechanics of syllogis- tic reasoning. According to the second group, intelligence is the capacity of an individual to adapt himself to new situa- tions. Whenever we are confronted with problems, questions, situations of one sort or another, which call for new modes of behavior, an adequate solution of the difficulty, if not accidental, is the result of the operation of “intelligence.” Whether “intelligence” has been utilized or not — and if used, to what extent— may be determined by appraising the result. What “intelli- gence” does is the matter of chief importance. Omy by a knowledge of the range of possible accomplishment and by our ability to measure differences in this capacity can we make practical application of the functioning of intel- ligence in such fields as education, delinquency, demc- tiveness, and industry. It is apparent upon careful analysis that neither of these definitions really touches rock-bottom. Severe in the standards by which definitions of those we examine are judged, we ourselves indulge in an infantile reaction for which we merit some condemnation. As mature, thinking people our definitions should certainly be “better than in terms of use.” To define intelligence as “adaptation to new situations” is but little superior to 170 that of an immature young’s ter who defined “soldier,” “to fight.” We wish to know what intelligence is, not what it does. Although the explanation of intelligence as “combinative ability” falls short of a complete definition, it does introduce us, however, more intimately to the basic processes underlying “intelligence-activity.” Psychologically considered, “adaptation” is a most complex activity, and intelligence cannot be defined as adaptation, because we are not here dealing with those elements which condition adaptation. The reader’s attention, at this point, may well be turned to our earlier consideration of the processes of analysis and synthesis. We noted there that these men- tal activities were of the greatest importance in the growth and development of hierarchies of mental functioning. No matter where our cross-section was made, whether at perception, ideation, judgment, reason- ing — there we found these phenomena, analysis and synthesis, explaining to a large extent the compounding and the unifying of processes and of mental material. We noted then that our ability to analyze a presented situation, is as important as our ability to synthesize details into a unity. Ebbinghaus, Ziehen, and Meu- mann overemphasize the importance of “ Kombinations- fahigkeit,” making slight if any mention of “analytic ability.” To that extent they fall short of a satisfactory definition of intelligence. To illustrate, suppose one is suddenly, and for the first time, confronted with this problem: Devise an instrument which will assist you in overcoming the effects of gravity. Immediately, numerous ideas come to one’s mind. Perhaps you think INTELLIGENCE MEASUREMENT THE RESULTS 171 of balloons, elevators, aeroplanes, feathers, birds, your body weight, electronic forces, etc., etc. The goal to be attained continually thrusts itself into your conscious- ness, often working havoc with what seems a perfect plan. Conditions of all sorts are considered, weighed, and measured. Handicaps of all varieties are met with and either they master you, or you master them. Be- fore you have proceeded very far upon your program of action, you have been dealing with a host of details — you have been comparing, discriminating, “analyzing,” “combining,” judging. Suppose now, some definite solution finally comes to you. Let us assume you have decided upon some intricate electrical mechanism. This decision would never have been reached had various details not been synthesized into what appeared, after a good deal of checking of experiments, a logical, practi- cal plan. Intelligent acts of all sorts require both an analysis of the situation which confronts one, a critical inquiry into methods of solving the problem, and a final synthe- sizing of details into a consistent whole. Our definition of intelligence as “adaptation” fails to take into ac- count the higher syntheses and analyses of the thinker, the scientist, the generalizer, the discoverer of laws. What factors of “adaptation” are there present in the propounding of a theory of heredity, of a doctrine of evolution, of a “periodic law,” of an electronic theory, of a cosmic hypothesis? Nevertheless, such syntheses are often the results of years of painstaking labor, critical search, and the keenest of insight. Few, if any, will deny that these are most decidedly the results of 172 INTELLIGENCE MEASUREMENT the highest type of intellectual functioning. It seems clear that the definition of intelligence as “adaptation” breaks down most emphatically at just this point. Intelligence more adequately defined would be ex- pressed as the ability of an individual to analyze and synthesize. Ability in this direction varies as does physical height. And there can be no intelligent adap- tion of any sort which is not conditioned upon these fundamental activities. Analysis and synthesis are the mechanics of intellectual behavior — adaptation to changing situations is but one of the many results. To return now to our original proposition, do the block designs measure intelligence? It may be stated in reply that there seems to be no reasonable doubt, substantiation having been obtained through introspec- tions, that these tests require first, the breaking up of each design presented into logical units, and second, a reasoned manipulation of the blocks to reconstruct the original design from these separate parts. The results of this activity, it is presumed, yield a fair index of this analytic-synthetic power which we have termed “in- telligence.” 2. VALIDITY To measure the validity of any newly devised test of intelligence is not a simple matter. It devolves upon the standardizer to present evidence that the new in- telligence scale measures this inadequately defined entity “intelligence” with approximately the same degree of accuracy as those standards or “measuring rods” now commonly accepted and in current use. THE RESULTS 173 In the following sections the writer will limit his dis- cussion to ten criteria, although admittedly, these are neither exhaustive nor of equal importance: (1) The mental processes employed; (2) Increased in score from year to year; (3) Correspondence of median mental ages; (4) Correlations between mental ages and intelli- gence quotients; (5) Correlations with teachers’ estimates of intelli- gence, and with school standing; (6) Conformance of intelligence-quotient distribu- tion with normal probability; (7) Correlations with vocabulary; Trabue B and C and Military Test; (8) The probable error of a block-design mental age; (9) The segregation of the feeble-minded; (10) Percentage ratios of agreement and disagreement with established standards of intelligence. (1) Mental Processes Employed In devising and standardizing this test the writer did not approach the problem with any bias of “faculty psychology.” The idea still seems prevalent, though not as much now as in the immediate past, that in order to possess an adequate measuring instrument for intelli- gence, the device must contain separate tests for each mental “function”: sensation, perception, association, imagination, memory, judgment, reasoning, etc. On the other hand, it has been amply demonstrated that the only intelligence scales worth the name draw service freely from all “functions.” Binet has pointed out that 174 INTELLIGENCE MEASUREMENT all “intelligent operations” involve the functioning of three primary activities: first, attention to the problem presented; second, a conscious attempt on the part of the subject to consummate an adequate adaptation to the situation; and third, the exercise of auto-criticism in order to determine how efficiently the specific “adap- tation” has solved the problem. Put in somewhat different words,1 “Binet’s conception of intelligence em- phasizes three characteristics of the thought process: (1) its tendency to take and maintain a definite direction, (2) the capacity to make adaptations for the purpose of attaining a desired end, and (3) the power of auto- criticism.” (p. 147.) A cursory examination of the demands made upon the mental operations of the person tested with the block designs will clearly reveal that attention, adaptation, and auto-criticism are all involved in the successful accom- plishment of each task. That point in the graded series of designs at which a child will begin failing to achieve further success, will be a rough measure of the develop- ment of his ability to attend, to adapt, and to critically survey his general plan of performance and his ultimate accomplishment. In his discussion of the ‘patience test’ in the 1908 scale, and these words might as well apply to the block-design tests, Binet states:2 “ It is a game, but at the same time a work of the intelli- gence. When one analyzes the operation it is found to 1 L. M. Terman: “The Stanford Revision and Extension of the Binet- Simon Scale for Measuring Intelligence” (Warwick & York, 1917; 179 p.). 2 “The Development of Intelligence in Children,” Publication No. II (Vineland, 1916). THE RESULTS 175 be composed of the following elements: (i) Conscious- ness of the end to be attained, that is to say, a figure to be produced; this end must be understood, and kept in mind; (2) the trying of various combinations under the influence of this directing idea, which often unconsciously determines the kind of attempt which should be made; (3) judging the combination formed, comparing it with the model, and deciding if it resembles the other.” (p. *95 •) If “ intelligence” involves the following mental opera- tions: analyzing, combining, comparing, deliberating, completing, discriminating, judging, criticising, and deciding, then the block-design tests may, with justice, be said to call upon the functioning of intelligence and to that extent they are a measure of that mental capacity. (2) Increase in Score from Year to Year As regards the second criterion, reference to Graph 6 and to the various tables of Chapter IV will clearly reveal that this requisite is satisfied. By itself, this evidence would be wholly inconclusive, for the reason that growth in height and in weight also show rising increments with every year of increasing life age, yet these values are not diagnostic of mental growth. It is only in relation to other standard criteria that the evidence of yearly increments has any validity. A slight diversion from the main theme of this section may not be out of place. A matter worthy of note is the lack of consistence in the variability of one mental age (Binet) in terms of the other mental age (block-design) at various age levels (see Table LXX). Thus up to Binet-age 7, and after 176 INTELLIGENCE MEASUREMENT Binet-age 16, the variability in comparable block-design age is slight, but from Binet-age 7 variability increases, reaching a maximum at Binet-ages 10 and n, and decreasing thereafter to Binet-age 17. Binet-Age and Block-Design Age TABLE LXX Binet-Age Block-Design Age 3 4 5 6 7 8 9 IO II 12 i3 14 15 16 17 18 19 Total Below 5 3 7 i4 14 3 i I 43 6 • IO IO IO 2 3 3 I i 40 7 • 2 7 9 7 2 i I 29 8 . 4 3 4 IO 4 2 2 I 3° 9 • i 3 14 6 7 I 4 2 3» IO • 2 6 5 8 5 2 3 2 33 u # 6 2 4 9 4 I i 27 12 # I i 2 6 8 3 4 2 I 28 13 . I 3 7 5 3 I I i 22 14 . 2 3 2 7 4 2 20 IS . 2 3 5 3 4 I 18 16 . I 2 i I I 2 i 3 12 17 I 2 4 1 3 2 i 14 18 • i 2 3 19 i 2 i 4 20 • 2 2 I 5 Total . 3 7 14 3i 2Q 5i 37 44 44 3i 20 17 ii II 7 4 5 366 (Note: Age io means 10-7 to. 11-6, etc.) Rather than regarding this condition a handicap, invalidating the tests as a differentiating mechanism for diagnosing feeble-mindedness, it appears, on the con- trary, to possess distinct advantages. Too frequently do the Binet tests leave us uncertain as to defmitemen- tal classification after obtaining a quotient of 73 or 76. Other evidence in the case, educational, social, biological, THE RESULTS 177 industrial, medical, is either meager or inconclusive. We wonder whether the child’s superiority in memory, for example, may not account for a higher quotient than he probably actually possesses. At other times, we are at a loss to account for exceptional success in one or more of the tests in higher ages, unless it be explained on the basis of previous familiarity. It is at such times that an additional differentiating mechanism, such as the block- design tests, may be of pronounced value in forming a more definite decision as to further social and educational handling. Suppose, for example, we have just concluded the examination of a child whose life age is 15 years, and who obtains a Binet mental age of n. The I. Q. in this instance would be 74. If then the block-design tests are given, on the basis of Table LXX, this Binet n-year-old may theoretically obtain a mental rating anywhere be- tween 6 years and 17 years on the block-design tests — a possible divergence of five years in either direction. The value of this apparent disagreement will be self- evident to psychoclinicians who are daily confronted with the need for rapid, yet accurate, prognostic diag- noses. In the above-mentioned instance, an I. Q. of 50 on the block-design tests coupled with a Binet I. Q. of 74 and a rather negative history of self-dependence might be of unquestioned assistance in outlining a rational plan for further care and direction of a subject under examination. The same value, of course, would attach to a block-design test-result in the case of a child with a Binet I. Q. of 74 and with a block-design I. Q. of 150. 178 INTELLIGENCE MEASUREMENT In view of a later return to this same matter, the diagnostic importance of this divergence will not be stressed any further at this point. (3) Correspondence of Median Mental Ages At each life age do the median mental ages obtained by the block-design tests correspond with the median mental ages obtained by the Binet tests? This question is an important one, and the extent of correspondence or deviation should measure very largely the validity of the newly devised tests. In the following table this comparison is presented: Correspondence of Median Mental Ages TABLE LXXI Lite Age Yrs. No. OF Cases Median Binet Age Yrs.-Mos. Median Block- Design Age Yrs.-Mos. Difference Between Medians (Mos.) Average of Two Medians Yrs.-Mos. 6 . . i6 6- 1 5~ 3 10 5- 8 7 • • 27 7- 5 6— 8 9 7-V2- 8 . . 28 8- 0 8- 2 2 8-1 g . . 27 9- 0 8-11 I 8-1i34 IO . 33 9- 8 10- 3 7 9-11J4 ii . 30 10- 6 11- 6 12 n- 0 12 . 29 II-IO 12- s 7 12- 1 y2 13 • • 32 11- 5 12-6 13 II-IlJ'S} 14 • • 28 13- 9 13- 6 3 13- 73^ IS • • 19 13- 3 14- 0 9 13- 7xA 16 . 16 IS- 6 13-10 20 14- 8 Average—8.5 Four important items are worthy of note: In the first place, the average deviation of the median Binet ages from the life ages at each year is 6 months; second, the average deviation of the median block-design ages from THE RESULTS 179 the life ages at each year is 8.8 months; third, the average deviation between the two intelligence-test me- dians is S}/2 months, and finally, the arithmetic mean of the two medians for each life age results in a more accurate approximation of what may he the “true” mental age than either median taken alone. We have, perhaps, in our early enthusiasm over the diagnostic accuracy of the Binet scale overlooked the importance and the need for calling to our assistance supplementary information which should aid us in arriv- ing more accurately at a positive diagnosis. The further our studies upon the fallibility of intelligence ratios continue 1 the more does it become apparent that, at least for the determination of mental deficiency, a Binet I. Q. alone is a hazardous symptom upon which to base a definite diagnosis of feeble-mindedness. Many and frequent have been the criticisms, sometimes mild, at other times venomous, that the accuracy of the Binet result was impaired by the intercipient factors of school- ing and linguistic facility. It may, consequently, not be a mistaken procedure to utilize both a language and a performance test in the determination of mental level ■— the performance test to compensate for the over- emphasis in the Binet scale of certain capacities not highly correlated with intelligence per se, the Binet scale to compensate for the inevitable easy-spread of ability characteristic of practically all performance intelligence- tests. 1 Florence Mateer: “The Diagnostic Fallibility of Intelligence Ratios,” Ped. Sem., 1918, 25:369-392. E. A. Doll: “The Growth of Intelligence,” Psychol. Monographs, 1921, Vol. 29. No. 2,130 p. 180 INTELLIGENCE MEASUREMENT After comparing the Binet age medians with the block- design age medians for each life age (Table LXXI), it may be sufficient to remark, in conclusion, that the approximation between the Binet and the block-design medians is remarkably close, especially when we con- sider that the block-design tests are free of [the “language factor” and of the influence of schooling. (4) Correlation between Mental Ages and Intelligence Quotients One of the greatest handicaps experienced in standard- ization is to select a standard of comparison! which is absolute. All existing standards are, unquestionably, affected by a variety of disturbing factors, frequently difficult to determine, and always difficult to discount. As in the year-scale standardization, the writer may have erred in selecting the results of Binet testing as a criterion of accurate mental age. That procedure, how- ever, was necessary because we have, as yet, no other equally accurate measuring stick — one which has attained a similar degree of general confidence. For the same reason, the Binet results are again utilized to check the validity, in the present instance, of the block-design ages. It may be of interest, first, to state the separate cor- relations of the two mental ages with life age. Con- formance with life age is, apparently, greater with the Binet than with the block-design tests. 1. The correlation between Binet age and life age is -f .80 (P. E. ± .01) (291 public school cases). THE RESULTS 181 2. The correlation between block-design age and life age is + .66 (P. E. ± .02) (291 public school cases). Segregating the results for the total 366 cases, for the 291. public school cases, and for the 75 feeble-minded the correlation between Binet age and block-design age follows: 3. The correlation between Binet age and block- design age is -f .82 (P. E. ± .01) (366 cases). 4. The correlation between Binet age and block- design age is + .81 (P. E. ± .01) 291 public school cases). 5. The correlation between Binet age and block- design age is + .67 (P. E. ± .05) (75 feeble- minded cases). The lower correlation between Binet and block-design ages for the feeble-minded is sufficiently great to require some comment. The application of the tests to the feeble-minded was purposely divided, in point of time: the first group of feeble-minded cases (28) were examined at Vineland, the summer of 1917; the second group (47) at the Sonoma State Home (Eldridge, Cal.), were tested during the spring of 1918. Almost one year later, because of accumulated experience with the block-design tests the outstanding deviations in performance of some of the feeble-minded could be more intelligently interpreted. Dr. George Ordahl, the psychologist of the Sonoma State Home, remarked during the period of experimenta- 182 INTELLIGENCE MEASUREMENT tion that the block-design tests seemed to measure functional efficiency to a far greater degree than did the Binet tests. Looking back to the writer’s personal knowledge of the cases at Vineland this remark was corroborated. It appears that many feeble-minded actually work at a higher level of complexity and ef- ficiency than one would expect on the basis of Binet mental age. For the reason that the Binet possibly underestimates the work-capacity of certain timid or retiring or inexpressive types of defectives, or for the reason that the block-design tests possibly place less emphasis upon verbal expression and more upon per- formance, it seems that in certain instances the feeble- minded obtain inconsistent scores on the two scales, yet their ratings by the block-design tests are a fairer index of their functional efficiency in various occupations than the Binet. This is a matter which can well afford further in- vestigation. There still remain unchartered territories without number awaiting exploration by those interested in determining individual differences among the feeble- minded as well as the differences between the normal and the feeble-minded. As regards the correlation between the I. Q.’s of the Binet and the block-design tests, the results again are segregated for the total 366 cases examined, for the 291 school children, and for the 75 feeble-minded. These follow: 6. The correlation between Binet I. Q. and block- design I. Q. is + .80 (P. E. ± .01) (366 cases). The table is herewith presented: THE RESULTS 183 TABLE LXXII Binet I. Q. and Block-design I. Q. Binet I. Q. Total . Block-Design I. Q. Osdn Go to m O O OsCa 4** Go ooooooooooooooo M M O M M m Go Go GJ o M 4^ M H -P>- 4* 0 H ON M H to Ca Os H Cn O M M H M 4*- 10 HI Os o to On to wCoOo-f*. 00HCO h *o O Ca M M -vj OsO M Os O M 00 o 68 t0HCnOOOtOj0.HMM o o 00 Go M to to M w Go Go 00 Go o O O Go to 8 4^ O m m Go *vj to Ca to o to mm tn C/i Cn io m to to o Os M to H M M Go O Go M M M o Go Os Os HHK)-fs^^-fSK)tOH(OtO m Go toGiCasO to Os 00-£* m 'O 00 O Go H o $ (Note: I. Q. of 50 means 46-55, etc.) 7. The correlation between Binet I. Q. and block- design I. Q. is + .58 (P. E. ± .03) (291 school children). 8. The correlation between Binet I. Q. and block- design I. Q. is + .67 (P. E. ± .05) (75 feeble- minded cases). The correlations of the two I. Q.’s, both for the total 366 cases and for the 75 feeble-minded are equal to the comparable correlations of the two mental ages men- tioned above. In the case of the 291 school children there is a marked difference, however. Whereas the correlation between Binet age and block-design age is + .81, the correlation between Binet I. Q. and block- 184 INTELLIGENCE MEASUREMENT design I. Q. is only -f- .58. It is difficult to explain this discrepancy, both tables having been checked for ac- curacy on three different occasions. The only plausible explanation at this time is the greater range of the mental age table as compared with the I. Q. table. The latter has fewer class-intervals, I. Q.’s having been taken in ranges of ten each. In this connection may also be presented the individual deviations in I. Q. between the Binet and the block- design tests. No one would expect exact correspondence, yet a high percentage of agreement should be demanded. In the following tables, segregated for the 291 public school children and for the 75 feeble-minded, this cor- respondence is presented. TABLE LXXIII Correspondence of I. Q.’s (201 P. S. Cases) Freqtjencx I. Q. B. D. I. Q. Higher B. D. I. Q. Lower Total Same i-5 27 29 7 56 6-10 35 22 57 11-15 20 28 48 16-20 25 22 47 21-25 •••#••• 16 XI 27 26-30 12 5 17 31-35 6 6 12 36-40 3 2 5 41-45 5 3 8 46-50 3 1 4 51-55 2 2 56-60 1 1 Median I. Q. Difference . 15 13 14 THE RESULTS 185 From the above table it is evident that 50 per cent of the cases show no greater deviation than 14 I. Q. be- tween the two tests. It is also clear that there are almost as many lower deviations as higher: The total number higher — 155 cases (53%) The total number lower — 129 cases (44%) The total number the same — 7 cases (3%) If anything, the block-design tests err in the direction of leniency rather than severity of mental age estima- tion. The closeness of correspondence is again apparent from the following analysis: Total deviations no greater than 5 I. Q. 63 cases (22%) “ “ “ “ “ 10I.Q. 120 cases (41%) “ “ “ “ “ 15 I. Q. 168 cases (58%) “ “ “ 20 I. Q. 215 cases (74%) “ “ “ “ “ 25I.Q. 242 cases (83%) “ “ “ “ “ 301. Q. 259 cases (89%) “ “ “ 35 I- Q- 271 cases (93%) For the feeble-minded, the data runs parallel,1 except that to a certain extent the figures are much more significant in comparison with the same group of data for the 291 P. S. cases, and from the point of view of the diagnostic efficiency of the block-design tests. So in Table LXXIV the correspondence of I. Q.’s for the 75 feeble-minded cases is presented: 1 It should be stated that all block-design zero scores were given a mental age rating of 5 years 3 months. This inaccuracy increases the I. Q. deviations. But this was purposely done in order artificially to increase the differences between the two I. Q.’s wherever possible. The comparisons throughout are, therefore, quite_conservative. 186 INTELLIGENCE MEASUREMENT Correspondence of I. Q.’s TABLE LXXIV (75 F. M. Cases) *J Frequency I. Q. B. D. I. Q. Higher B. D. I. Q. Lower Total Same i- s 15 13 3 28 6-10 S 13 18 11-15 6 3 9 16-20 2 3 5 21-25 1 2 3 26-30 1 3 4 31-35 2 2 4 36-40 1 1 Median I. Q. Difference . 6 8 7 It is clear from this table that 50 per cent of the total feeble-minded examined show no greater deviation than 7 I. Q. between the two tests. This similarity of results indeed merits special emphasis. It will also be noted that whereas, for the average school child, there is a strong tendency to secure a somewhat higher score on the block-design tests, this is reversed for the feeble- minded. The latter group tends to secure lower scores. This is evident from Table LXXIV, and also from the following totals: The total number higher — 32 cases (43%) The total number lower — 40 cases (53%) The total number the same — 3 cases (4%) This evidence is in harmony with the remark pre- viously made, that the block-design tests assist in the THE RESULTS 187 differentiation of the feeble-minded from the border- zone or the normal case. Although the above-mentioned differences exist be- tween the two I. Q.’s, yet correspondence is higher for the feeble-minded than for the public school group: Total deviations no greater than 5 I. Q. 31 cases (41%) “ “ “ “ “ 101. Q. 49 cases (65%) “ “ “ “ “ 15 I. Q. 58 cases (77%) “ “ “ “ “ 201. Q. 63 cases (84%) “ “ “ “ “ 251. Q. 66 cases (88%) “ “ “ “ “ 301-Q. 70 cases (93%) In conclusion, it may be stated that the correlations be- tween the two test methods, considering their marked dif- ference in character, are high enough to guarantee frequent correspondence between their mental ages and I. Q.’s. (5) Correlations with Teachers' Estimates and with School Standing The search for the “fountain of youth” presented few if any greater difficulties than the search for criteria by means of which to weigh the validity of measuring instru- ments for intelligence. It is comparatively easy to devise tests, to develop an efficient technique for application, to establish norms, and to obtain results which may possess some psychological, educational or social significance. But to find a stable criterion for establishing validity appears almost hopeless. It has been customary to rely upon teachers’ estimates of intelligence to check the validity of one’s intelligence- test schema. It is valuable to utilize this “common- sense” check, even though high correlations between teachers’ judgments and test results cannot be expected, 188 INTELLIGENCE MEASUREMENT and in spite of the fact that there are some very serious forces invalidating such judgments. It is clear that the same high I. Q. receives a lower estimate by the teacher if a child is in upper grades rather than in the lower grades, because of the elimination of poorer pupils in the upper elementary grades. Thus an I. Q. of 90 is more likely to receive an estimate of average or above average in the lower grades, whereas in the upper grades or in the high school the same I. Q. will more probably receive an estimate of below average or inferior. Other writers have already indicated other factors, having no bearing upon or relation to intelligence, which interfere with the accuracy of judgment on the part of teachers. School marks, also valuable criteria with which to check the results of a newly devised test, are also ineffi- cient to an extent, because they are generally crude, are limited to a rather narrow range, contain spurious ele- ments such as neatness, order, and so on, are often given for disciplinary reasons, or as bait for an educa- tional spurt, and are not based upon uniform standards. However, there is a corroborative value in teachers’ estimates and in school standing which is worth men- tioning. 9. The correlation between teachers’ estimates of intelligence and Binet I. Q. is + .47 (P. E. ± .03) (291 school children). 10. The correlation between teacher’s estimates of intelligence and block-design I. Q. is + .23 (P. E. ± .04) (291 school children). The table is here- with presented. THE RESULTS 189 TABLE LXXV Teachers’ Estimates and Block-design I. Q. Total Block-Design I. Q.1 Ostia W u h QC 0\Ca Cw ooooooooooooooo -t* to to ■f* M M to M Oo M M M to ca ca to M H to to Go OCa On to m On M Co H M to to to to h H to Ca Ca Go h On O m vO Ca h m >1 On 00 h Os-f>- *0 00-2 O OCMb H 00 to to Oo Oo Oo Go C/i m Oo m O Oj H H M 0 to O M H H H H MC*» NUiMO K> GOO -f» M M 3 > - Teachers’ Estimates > (30 signifies scores between 26 to 33, etc.i r = + .23, ± .04 Although the correlation between block-design age and Binet age is + .82, teachers’ estimates of intelligence correlate only one half as much with the block-design I. Q.’s as with the Binet I. Q.’s. The reader may recall that one of the original objections to the Binet scale was that it measured school training. Only to a limited extent has this been denied, the explanation having been made that the tests measure intelligence through the medium of knowledge only partly influenced by school training. It has been admitted, true, that practically all children are exposed to these educational influences, but the ultimate difference in achievement is explainable on 190 INTELLIGENCE MEASUREMENT the basis of differences in endowment. However this may be, the results of the block-design test would perhaps tend to show that there is more to this charge than we have been inclined to admit. It will, no doubt, be con- ceded without much question that the block-design tests are less affected by school training than the Binet. Regarding the correlations between school standing (school marks) and block-design I. Q. the following are the results: n. Block-design I. Q. and Reading: + .18, P. E. dz .04 (276 cases). 12. Block-design I. Q. and Language: -f- .20, P. E ± .04 (259 cases). 13. Block-design I. Q. and Household Arts: + .22 P. E. ± .09 (48 cases: 44 girls, 4 boys). 14. Block-design I. Q. and Drawing + .25 P. E. ± .04 (258 cases). 15. Block-design I. Q. and Arithmetic: + .31, P. E. ± .04 (251 cases). 16. Block-design I. Q. and Manual Training: + .36, P. E. ± .08 (58 cases: 56 boys, 2 girls). It will be observed that block-design results correlate least with reading and language, and most with manual training and arithmetic. When discussing sex differences in an earlier section of this monograph, attention was called to the slight superiority of boys over girls at the higher ages. It was mentioned then, that perhaps the mechanical nature of some of the higher designs gave boys a slight advantage. The evidence here is, to an extent, a corroboration of this view. This condition THE RESULTS 191 does not point necessarily to a weakness in the test scheme. It will be conceded by those who analyze the activity that success in manual training involves the utilization of intelligence in planning one’s work, in criticising one’s progress through the various stages of accomplishment, and in holding the goal to be achieved in mind and in attaining it. It would possibly be gen- erally admitted that efficiency in manual training draws no less upon “intelligence” than do reading and language. It may also be of interest to compare the average of the correlations between reading, language and arith- metic, the “mind” subjects on the one hand, and house- hold arts, drawing, and manual training, the “hand” subjects on the other. The averages of the two groups are -f .23 for the first subjects, and + .28 for the second. Again we find corroboration of the contention that the block-design tests are actually tests of performance, more free of the language factor than many of the tests, neces- sarily dependent upon language, now in common use. The need for the application of such a test as this in combination with others, in order to estimate accurately a child’s intelligence, appears self-evident. When the teachers were requested to fill out the ques- tionnaire they were asked to answer this question for each child examined: “If this child were given a mental test involving chiefly the use of language, or the ability to understand and handle language symbols (as con- trasted with a test requiring silent observation and performance) would you expect him (her) to pass; very- low, low, below average, average, above average, high, 192 INTELLIGENCE MEASUREMENT very high?” It was expected that the replies to this question would bring to light those cases where undue superiority or undue inferiority in language understand- ing and expression might affect the results of a mental test dependent upon language symbols for comprehension and success. The correlation between block-design I. Q. and these estimates by the teachers follows: 17. Block-design I. Q. and teachers’ estimates of language vs. performance: + .24, P. E. ± .04 (291 cases). Analyzing the table of data it is found that 6 per cent of cases possessing I. Q.’s of 106 and over were estimated by the teachers likely to obtain very low, low, or below average scores on a “language” intelligence test, and at the other extreme 10 per cent of cases possessing I. Q.’s of 95 or under were estimated by the teachers likely to obtain above average, high, or very high scores on a “language” intelligence test. In other words, according to the judgment of teachers, it would appear that a total of 16 per cent, or one sixth of all children in the average public school, are likely to be misrated if judged by a “language” test alone. This proportion is probably too high. At any rate, the data is offered for what it is worth. By way of summary, it may be remarked that not only do the block-design tests show a reasonable correlation with school standing and teachers’ estimates of intelli- gence, but the emphasis upon performance as opposed to verbal impression or expression is a desirable feature of the test. THE RESULTS 193 (6) Conformance of Intelligence Quotient Distribution with Normal Probability A very necessary index in weighing the validity of any standardized test is to determine the extent to which an actually found distribution conforms to its theoretical distribution. The assumption that the distribution of intelligence follows normal probability is recognized as an arbitrary one, but it is utilized merely as a working hypothesis. If not this, what else? Until further investigation gives us more light on this problem we must continue to grope, more or less, in the dark. In the following table are presented the I. Q.-range distributions for the Binet and the block-design tests. The respective percentage values are compared with what one should theoretically expect. Attention is again called to the “spread” of ability greater for the block-design tests than for the Binet, previously mentioned. It is apparent that ‘ ‘ intelligence ’ ’ measured by the Binet test manifests a lesser diveristy than the block-design test. Which of the two is more truly representative it is difficult to state dogmatically. Perhaps an average of the two approaches more nearly the truth. It may be of interest to mention a note con- tained in a letter to the writer from W. A. McCall in which he remarks “that the distribution of Reading Quotients,” obtained from his recently completed reading scale, “conforms more closely to your I. Q.’s than Terman’s.” Whatever the true situation regarding the general character of the distribution of intelligence, the fre- 194 INTELLIGENCE MEASUREMENT 26 36 46 56 66 76 86 96 106 Il6 126 136 146 156 166 TO TO TO TO TO TO TO TO TO TO TO TO TO TO TO 35 45 55 65 75 85 95 105 ns 125 135 145 155 165 175 Stanford Binet Ob- tained Theoretical Expec- ,i-7 5-5 16.5 22.7 28.2 13-8 8.3 2.1 1.0 tation .... .16 1.6 8-5 23.42 32.64 23.42 8.5 1.6 .16 Block-deisgn Ob- tained Theoretical Expec- .034 .034 1.4 6-5 6.2 14.4 i5-i 18.9 14.4 10.0 5-2 5-2 .07 1.0 •034 tation (Median at 99) ... •49 1.28 2.78 5-21 8.67 12.05 14.66 15-3° 13.84 10.69 7.25 4.11 2.08 .88 •33 Intelligence Quotient Ranges TABLE LXXVI THE RESULTS 195 quencies of the block-design I. Q.’s conform more closely to theoretical expectation. Thus the average deviation from theoretical expectation for the Binet I. Q. ranges is 3.3 per cent per I. Q. group. The average deviation for the block-design tests is only 1.4 per cent per I. Q. group. In conclusion, the evidence of correspondence between the empirical and the theoretical distributions testifies to a fair degree of validity of block-design I. Q. (7) Correlations with Vocabulary, Trabue B and C, and Military Test Mention has already been made of the correlations between block-design and Binet test results. The data of the Stanford-Binet vocabulary, the Trabue Language Scales B and C, and the military test were also utilized to verify the accuracy with which the block-designs estimate intelligence. These criteria were especially chosen for the reason that, besides the inevitable differ- ences to be expected from the application of two intelli- gence scales, additional disturbing factors of language and group testing were added in order to exaggerate the inherent discrepancies. It was also the intention to obtain some information which would throw light upon the much mooted questions, “Does the Binet test exaggerate the importance of language in contradistinc- tion to performance?” and “Are there specialized capaci- ties of ‘doing’ which are as indicative of intelligence as those concerned with ‘talking’ and ‘information’?” This problem, however, can only be barely touched upon at this point. 196 In the following tables are presented, first, the correla- tions between Stanford-Binet mental age and Stanford- Binet vocabulary score, and second, between block- design score points and Stanford-Binet vocabulary score: INTELLIGENCE MEASUREMENT TABLE LXXVII Correlation between Binet and Vocabulary Vocabulary Score* Binet Mental Age Total 6 7 8 9 IO II 12 13 14 is l6 17 18 19 o- 4 4 4 8 5- 9 3 7 4 I I 16 10-14 6 4 9 1 I 21 iS-19 10 19 6 1 36 20-24 11 16 13 3 43 25-29 3 11 13 2 2 3i 30-34 2 11 12 5 3 33 35-39 I 3 11 4 1 1 1 22 40-44 I 10 7 4 1 23 45-49 I I 6 5 4 1 18 50-54 2 6 4 7 4 2 I 26 55-59 2 2 2 2 8 60-64 1 1 1 2 2 2 9 65-69 1 2 3 2 8 70-74 2 I 1 1 5 75-79 1 3 4 80-84 85-89 1 1 90-94 I 1 2 Total 13 25 36 44 43 30 20 17 11 II 7 4 5 314 r — + .91, P. E. ± .007 * These class-intervals, although not the best, were used in order to correspond with Terman’s. It may be worth remarking at this point that of the three children who achieved the highest scores on the vocabulary test, two were inmates of the institutions for the feeble-minded! On the block-design test, however, their mental incapacity is evident, one achieving a score THE RESULTS 197 between 21-30, the other a score between 71 to 80. The Binet ages of the two fell, for the first, between 14-7 and 15-6, and for the second, between 15-7 and 16-6. Referring to Table LXXVII, the correlation ratio + .91 is the same as that found by Terman in his analysis Correlation between Block-design and Vocabulary TABLE LXXVIII Block-design Score Points 6l 81 Score I II 21 31 41 51 71 91 IOI III 121 131 Total O TO TO TO TO TO TO TO TO TO TO TO TO TO IO 20 30 40 So 60 70 80 90 ICO no 120 130 o- 4 • 35 18 4 3 60 5“ 9 • 2 9 2 1 1 I 16 10-14 • 5 10 5 I 21 15-19 . 14 10 8 3 I 36 20-24 . 1 14 14 3 4 3 1 1 I 1 43 25-29 • 5 6 8 2 3 5 2 31 30-34 • 5 2 4 4 5 2 5 2 3 1 33 35-39 • 2 1 2 2 2 2 3 3 1 2 I 1 22 40-44 . 2 4 4 2 2 1 2 1 1 2 1 I 23 45-49 • 2 2 1 5 3 2 I I 1 18 50-54 • 1 2 3 3 1 3 2 3 4 2 2 26 55-59 • I I 1 1 2 2 8 60-64 • 1 1 1 1 2 2 1 9 65-69 . 1 2 1 4 8 70-74 • 2 1 2 5 75-79 • 80—84 • 2 1 1 4 85-89 . 1 1 90-94 • 1 1 2 Total . 43 80 47 43 23 26 16 15 16 10 10 18 7 8 3 365 r = + -77, P. E. ± .02 of the records of 631 school children,1 wherein mental age and vocabulary score were correlated. Based upon statistical analysis, not personal opinion, the vocabulary 1L. M. Terman: JThe Intelligence of School Children” (1919), p. 310. 198 INTELLIGENCE MEAS test stands out clearly as the best single test in the whole Binet series. The correlation ratio + .91 is to a certain extent spurious because vocabulary score entered into the estimation of mental age and to that extent weights the Binet mental age in its favor. In view of this condi- tion the correlation between Binet mental age and block- design mental age (+ .84) is not so much lower than one would conclude off-hand. Then, again, reference to Table LXXVIII and to Terman’s Table 411 reveals clearly that the variability of a block-design score in terms of Binet mental age is not so great, when we observe that the vocabulary test presents approximately the same degree of variability, and in spite of the fact that the vocabulary aided in the determination of Binet mental age. For 482 miscellaneous adults — hoboes, prisoners, delinquents and business men — Terman found the correlation between mental age and vocabulary to be + .81, three points lower than the correlation be- tween the Binet and the block-design tests. It is quite surprising to note the correspondence be- tween efficiency in the block-design tests and in vocab- ulary, the former apparently concerned with hand- manipulations, the latter with language, supposedly affected by schooling and experience. In the past we have been inclined to look to performance tests as “fillers-in” for the assumed inadequacies of the Binet tests. The high correlation between the two types of examination leads one to the conclusion that both systems call upon somewhat similar mental processes — processes involved in the normal functioning of intelli- 1L. M. Terman: “The Intelligence of School Children” (19x9), p. 3x0 THE RESULTS 199 gence. So that, although the two methods of expressing this mental power differ radically in character, the men- tal manipulations making for successful achievement are fundamentally the same. An analysis of the reactions of the feeble-minded to the two test systems reveals roughly three rather distinct groups. On the one hand there are what Binet has termed the “loquacious types.” These are the feeble- minded who have an easy facility with language, and who, because of their loquaciousness and ability to speak with apparent intelligence on many subjects, give to the lay mind the impression of average mental capac- ity, a sort of general ability and “intelligence.” These aments secure high scores in the vocabulary test, but their performance in the block-design tests is strikingly low. Then again, there are a number of others, con- siderably backward in speech expression and in language ability — what some have designated “ the silent type.” The character of their actual daily activity belies their mental rating on the Binet scale. Low in their achieve- ments on this intelligence test, they are nevertheless capable of considerable rather intelligent effort if taught to do something, and are placed upon their own initiative which will involve no greater than a few minor adapta- tions. These mental deficients although markedly un- intelligent on a test involving the understanding and the use of language, nevertheless are capable of a con- siderable amount of useful and complex effort on the institution grounds. Those who have actually worked with the feeble-minded in their institutions will readily recall numerous instances which are corroborative of 200 INTELLIGENCE MEAS the above remarks. Finally, there are those aments who manifest the same degree of intelligence-develop- ment by both tests. This group, of the three, is ap- parently the largest. It appears that our earlier notion that language capacity and performance were two somewhat mutually exclusive abilities was to a large extent erroneous. Granted a certain level of intelligence-development, the vocabulary test or the Binet scale are, in most cases, no less effective measures of that level than a reliable performance test itself, no matter how carefully or efficiently devised or standardized. But, in case of doubt, both tests may be given to advantage, averaging the results of the two. What has already been said regarding the relation between the diagnostic efficiency of a language test and a performance test holds true for such a language test as Trabue B and C. Devised originally to measure pedagogical achievement in language, it was found very early to be also diagnostic of intelligence-development. It is again surprising to note the relatively close cor- respondence in scores between this language and the block-design tests. See table on the next page. The correlation of: + .57 between these two test schemes is indicative of a certain amount of common mental activity characteristic to both, irrespective of outward differences in the physical form of the tests themselves. An analysis of the regression of the block design on Trabue score may be of interest. From the table it is evident that as Trabue score increases, the increase THE RESULTS 201 in block-design score is relatively slight. When, however, the middle range of Trabue scores are reached the in- crease in one is paralleled by similar increases in the TABLE LXXIX Correlation between Trabue B and C and Block-design Scores Trabue Score B AND C O I TO IO II TO 20 21 TO 30 O O M 41 TO SO SI TO 60 6l TO 70 71 TO 80 81 TO 90 91 TO IOO 101 TO no III TO 120 121 TO 130 131 and over Total o- I . . 7 18 5 1 I 32 2- 3 • • 1 I 4- 5 • • 1 1 I 3 6- 7 . . 1 2 1 4 8- 9 . . 3 1 4 I 9 io-ii . . 1 8 2 I 12 12-13 • • 7 1 5 2 1 1 17 14-15 . . 4 2 6 16-17 • • 4 3 3 I 2 1 1 1 16 18-19 • • 1 2 5 2 I 1 2 14 20-21 . . 3 4 8 2 3 1 I 2 1 25 22-23 . . I 4 3 2 5 I 3 1 2 3 1 26 24-25 . . 2 1 1 2 4 2 3 3 1 1 1 21 26-27 . . 5 4 5 3 4 I 3 3 2 3 I 34 28-29 • • X 1 2 4 1 2 2 2 3 18 30-31 • • I 3 2 1 2 3 2 2 16 32-33 • • 1 1 2 4 34-35 • • I 1 4 1 2 I 10 36-37 • • 1 1 1 I 4 38-39 • • 1 1 Total . 9 55 32 37 21 25 14 15 13 10 8 16 7 8 3 273 other, except that the higher the Trabue score the greater the variability in terms of block-design score. So vice versa, the lower the block-design score the greater the variability in terms of Trabue score. This condition may be interpreted as indicating that at the lower ages facility in language is rather low, so that block-design scores are higher at any given age. On the other hand, r = + .57, P. E. ± .03 202 INTELLIGENCE MEASUREMENT the reverse is true for the higher ages: Trabue scores here seem to possess higher diagnostic efficiency. A number of the children who were included among those tested for block-design ability had been given the military test when it was in its early stages of standard- ization. This again is a test in which the “language factor” plays no insignificant part, yet is a recognized instrument for intelligence estimation. The cases which could be included in this analysis were limited, but the results may be of interest. The table follows: TABLE LXXX Correlation between Military and Block-design Scores Block-design Scores Military Test I II 21 31 41 SI 6l 71 81 91 IOI III 121 131 Total Score O TO TO TO TO TO TO TO TO TO TO TO TO TO and IO 20 3° 40 So 60 70 80 go IOO no 120 130 over o- 19 2 9 3 5 1 20 20- 39 2 4 4 10 40- 59 1 5 5 1 I 1 14 60- 79 1 3 I I 1 1 8 80- 99 2 1 3 2 1 9 100-119 2 1 1 I 1 1 7 120-139 3 3 2 2 I 11 140-159 2 3 6 1 2 4 1 19 160-179 1 2 5 3 2 2 1 1 17 180-199 i 1 2 2 I 2 1 10 200-219 1 1 2 2 3 3 1 13 220-239 1 2 I I 2 1 8 240-259 1 1 2 2 2 8 260-279 2 2 3 7 280-299 1 2 3 300-319 1 1 320-339 1 1 340-359 360-379 1 1 Total 2 18 20 27 11 16 10 10 12 4 5 15 7 7 3 167 r — + .71, P. E. ± .02 203 THE RESULTS The correlation + .71, between the military test and the block-design test, although surprisingly high to those accustomed to regard “performance” and “linguistic ability” as separate and distinct capacities, is neverthe- less to be expected in light of the fact that both test schemes aim to measure intelligence. In the following tabular arrangement the correlations of the block-design test with the three tests in which “language” plays an important role are given: 1. Block-design test and Binet Vocabulary . + .77, P. E. ± .02 2. Block-design test and Trabue B and C . + .57, P. E. ± .03 3. Block-design test and Military . . . + .71, P. E. ± .02 In order to determine whether the correlations between the block-design test and the three tests designated as involving the use of language might have been higher but for the interference of this “language” factor, the scores of the Binet vocabulary and the military test were correlated, both having the “language factor” in com- mon. It is presumed that if these latter two tests show no greater correlation than either test with the block- designs, that other factors than language facility enter to lower the correlation from -f- 1.00. The correlation between Binet vocabulary and mili- tary test is + .87, P. E. dh .02 (167 cases). It is, consequently, apparent that other disturbing factors than “language” are operative tending to reduce the correlations between these three tests. The cor- relations between the block-design and any one of the three other tests is not very appreciably lower than the correlations between any two random “language” in- telligence tests. 204 INTELLIGENCE MEASUREMENT This brings us to our original problem, “Does the Binet test exaggerate the importance of language in contra- distinction to performance?” If such a condition does exist, its importance has been greatly overemphasized in the past. And to our other question, “Are there specialized capacities of ‘doing’ which are as indicative of intelligence as those concerned with ‘talking’ and ‘information’?” a rational reply based upon our statisti- cal data would include the remark that there are no such compartment-like functions, and that facility in one direction is highly correlated with facility in the other. From the point of view of the validity of the proposed test-scheme, the block-design tests, the above-mentioned correlations between this performance test and typical language-intelligence tests bear out the contention that the block designs measure intelligence rather effectively. (8) The Probable Error of a Block-design Mental Age The consistency with which a newly-devised measur- ing instrument estimates presented values may be re- garded a fair index of its validity. Extreme variability and haphazard deviations from normal expectation may be interpreted as indicating lack of efficiency in evalu- ating quantitative differences. On the other hand, re- peated identity of determined values for any given objective quantity argues for proficiency of the measur- ing tool. It is, therefore, regarded important to de- termine to what extent, and with what probability, extreme deviations of significant magnitude may be expected. THE RESULTS 205 The probable error (P. E.) is the statistical device whereby such consistency may be computed. In his study of vocabulary, Terman found1 the prob- able error of a mental age based upon vocabulary score alone to be 9.6 months (631 children). In other words, based on vocabulary alone, mental age thus determined will not deviate from the mental age derived from applying the entire Stanford-Binet scale more than g}/2 months in 50 per cent of cases. The table of ratios follows: Deviation Per Cent of Cases 9)/2 mos 5o 12 mos 40 18 mos 24 mos 10 36 mos r = + .91 A difference in mental age as great as three years may be expected in only one case out of ioo, and a difference of two years in only i out of io. Or, put differently, taking any obtained score, the chances that it is within one year correct (one year above or one year below) are 60 that it is, to 40 that it is not. The chances that the score is within two years of the correct mental age are 90 to 10, and within three years, 99 to 1. For adults the vocabulary test did not function as efficiently. The probable error of a mental age based 1Terman, Lewis M., Kohs, S. C., and others: “The Vocabulary Test as a Measure of Intelligence,” Journal of Educ. Psychol., October, 19x8 206 INTELLIGENCE MEASUREMENT upon the vocabulary score with this group of cases was 12 mos. The table of ratios follows: Deviation Per Cent of Cases 12 mos So 18 mos 3i 24 mos 18 36 mos 4-3 r = + .81 A divergence greater than one year between mental age as determined by the vocabulary alone and that of the Binet scale applied as a whole was to be expected in 50 cases out of 100. A two years’ divergence or mbre had only 18 chances out of 100 in its favor, and the chance that a mental age was within three years correct was 95.7 to 4-3- In the light of this information it may be of interest to present the probable error of a mental age derived from the application of the block-design tests. The data of the table on the opposite page were secured frohi the figures of Table LXX (p. 176). Although the median quartile deviation is approxi- mately two months lower than the average (arith. mean) quartile deviation, the latter, although less favorable to the block-design tests, will be utilized in this analysis. The data of Table LXXXI indicate that the probable error of a block-design mental age in terms of Stanford- Binet mental age is about 16 months. In other words, th'e chances are that a mental age based upon block- design performance will not be incorrect more than 16 THE RESULTS 207 Block-design Age IYks.) Below 6 6 7 8 9 IO II 12 13 14 is l6 17 18 19 20 No. of Cases 43 40 29 30 38 33 27 28 22 20 18 12 14 3 4 5 Median Binet Age * . . 64 90 98 108 120 129 133 138 144 149 181 186 181 191 202 Qi • • • 56 78 88 93 96 104 108 121 130 126 137 138 177 160 181 195 Q* . . . 73 102 109 120 I23 136 138 150 i57 164 165 217 209 204 229 207 Quartile Devi- ation . 8-5 12.0 10.5 13-5 13-5 16.0 15.0 i4-5 13-5 19.0 14.0 39-5 16.0 22.0 24.0 6.0 Median Binet Ages for Each Block-design Age * The figures in the body of the table are in terms of months. Average Quartile Deviation . . 16.1 mos. Median Quartile Deviation . . 14.25 mos. TABLE LXXXI 208 INTELLIGENCE MEASUREMENT months in at least 50 per cent of the cases examined. The table of ratios follows: Deviation Per Cent of Cases1 12 mos 61 16 mos 50 18 mos 45 24 mos 3i 30 mos 36 mos 13 42 mos 8 48 mos 4 r = + .84 A difference in mental age as great as four years may be expected in only 4 cases out of 100, a difference of three or more years in only 13 cases out of 100, and a difference of two years or less may be expected in 69 cases out of 100. Based upon this criterion alone the block-design test appears to have about 56 per cent the diagnostic power possessed by the Binet vocabulary. (9) The Segregation of the Feeble-minded Although at the present time the writer has no evidence to adduce other than his experience coupled with a certain insight into the general condition of feeble- mindedness, it seems reasonable to assume that feeble- mindedness is not an arbitrary psychological and 1 These results have been derived through the use of Sheppard’s table of values of the normal probability integral modified for interpo- lated terms and presented in Table XC in Appendix III. Because of the interpolations this table may be found to possess greater utility than Thorndike’s “Mental and Social Measurements” (2d ed., p. 200) or Buckingham’s “Spelling Ability,” p. 35 and p. 116. THE RESULTS 209 statistical designation which fluctuates and changes as do our moral standards. After years of effort in this field one cannot help but be led to the conclusion that mental feebleness is merely one of the surface indications of general physiological incompetence. This notion is expressed as follows by Cabot: “Our best social diagnoses, such as idiocy or feeble- mindedness, do not refer to the mind only. They refer to the body just as much. Feeble-mindedness is a state- ment about the child’s body, his brain, his voracious appetite, the diseases to which he is likely to succumb, his extraordinary susceptibility to cold, and his poor chances of growing up. One says a great deal about the physical side of a child, as soon as one pronounces the word ‘feeble-minded.’”1 It is just this aspect of the general problem which has been overlooked by those whose only basis for the term “feeble-mindedness” has been the “normal curve of distribution.” Mental deficiency is a general, disordered, physiological condition, which transcends such simplicity of definition or understanding. It has frequently been argued that because the results of an intelligence test yield, what appears to the eye, a normal distribution curve, this in itself is complete proof that human intelligence is a perfectly-graded, homogeneous entity. The writer, at this time, merely wishes to call to the reader’s attention the important discussion by Boring2 in which he points to the fact that 1 Richard C. Cabot: “Social Work,” (Boston: Houghton, Mifflin Co., 1919; 188 p.), pp. 107-108. 2 “The Logic of the Normal Law of Error in Mental Measurement,” Amer. J. of Psychol., 1920; 31:1-33. See especially pp. 12, 13, and 15. 210 INTELLIGENCE MEASUREMENT whereas Merriman’s frequently quoted table of shots aimed at a target is generally utilized to illustrate the functioning of the normal law to errors, nevertheless “Pearson showed that the distribution of shots at a target, given by Merriman, is best represented by the sum of normal curves.” For the same reason there is room for belief that possibly the curve for human in- telligence, which in reality is not “normal” but skewed, may be the composite of two (perhaps more) separate curves, perhaps “normal,” perhaps not, each represent- ing measurements of somewhat distinctively separate groups. Any test devised to measure intelligence has a specific bearing upon the general problem of the clinical differ- entiation of the feeble-minded. The present test has been purposely devised to be of especial assistance in this general direction. After wrestling with various problems of clinical psychology for a number of years, one of the pressing outstanding questions appeared to be that of the borderzone case. A number of mental ex- aminers apparently are content with designating a child “borderzone intelligence,” and allowing the matter to rest there. This is especially true of those who have been given to a rather arbitrary ultilization of the Binet scale, chopping off cases into groups on the basis of I. Q. alone. So, in spite of the fact that any determined I. Q. may be in error 2 or more points in 50 per cent of the cases, if Johnny Smith is 79 I. Q. he is a “borderzone case,” but if it happens to be 81, he is just dull normal! Clinical psychology, to gain substantial recognition, must take itself more seriously! Binet I. Q. is merely THE RESULTS 211 one of the minutiae of an adequate diagnostic syllabus. And a final summation of information from the psycho- logical, educational, social, medical, vocational, and biological fields is considerably more than can be epito- mized in a brief label of one or two words. The writer is making a plea, not for the abandonment of intelligence classifications as such, but rather that the psycho-clinician dictate his classification, and not allow the classification to master and dictate to him. There are frequent occasions when established classifications fail to fit a specific case. That is the time when the efficient examiner manifests his mettle and his intelligence by freeing himself from any previous systematized procedure and analysis, and arrives at the truth by other channels and other criteria. Looking at the matter from a social and practical point of view, those who engage the services of trained clinical psychologists do not look for any half-baked theories or any speculative conclusions about certain individuals or families who are distinct social problems. They require definite, practicable, intelligent recommen- dations, based upon a thorough and scientific analysis of the factors involved. Shall this child be sent to an institution for the feeble-minded? Can Mary, aged nineteen, be held responsible for her acts? What shall we do with Johnny, the recidivist, father insane, mother out working? Shall the Jones family, consisting of step- father, mother, and eight children, be broken up? Ought we to sterilize William? Shall we place Mrs. Smith as a domestic? Shall Tom be sent to the insane asylum or the penitentiary? What can we do for the Thompson 212 INTELLIGENCE MEASUREMENT family, a typical instance of continued dependency running over a considerable period of years? And so on, ad infinitum. All along the line the life, happiness, and futures of our fellow human beings are being placed in the balance, and we aid in tipping the balance, up or down. Terms such as “borderzone intelligence” based upon the Binet test mean little if anything in writing out a prescription for action necessary to be taken in each of the above-mentioned instances. The social worker who is to handle a case wishes to know whether there is reason to hope for a moderate degree of success at social rehabilitation, or whether hope of success is unthinkable in the light of existing handicaps and social forces. To him a person is normal or not, well or not, dead or alive. One who is feeble-minded should not be handled as nor- mal, he who is normal should not be handled as feeble- minded. For the feeble-minded the road-directions point one way, for those who are normal they point in the opposite. There exists no borderzone. Whatever theories we may hold regarding the develop- ment, the distribution, the varieties and classifications of intelligence, a person presented for examination is or is not feeble-minded. Our determination of this fact may take on various degrees of expertness. In standard- izing the block-design tests the writer was motivated by a desire to devise an additional tool which might assist in an intelligent determination of whether a person was or was not feeble-minded.1 Among ourselves we may 1 As used here, the term “feeble-minded” is understood to be based upon a thorough analysis of all phases of a person’s past and present history taken from all diagnostic angles, and not upon the Binet test alone. THE RESULTS 213 create all sorts of fantastic notions and classifications about which we may pleasantly wrangle, such for example as the “borderzone group,” some of us believing that that group represents the overlap between normals and feeble-minded, and others of us maintaining that that group is a distinct, clear-cut entity, — but to the prac- tical worker engaged in curing the ills of humanity these “fantastic notions” mean next to nothing. What has been said may appear a rather unique and veiled return to an earlier contention regarding the “borderline case”1 which some may have expected the writer to have abandoned after some hoped-for increase in maturity and knowledge! The chief purpose, however, in the present instance was to emphasize the importance of “differentiability” which a good test of intelligence should possess. For a very adequate discussion of the borderzone question the reader is referred to Miner’s monograph “Deficiency and Delinquency.”2 Five cases have been selected from the writer’s most recent clinical experience to illustrate the assistance which the block-design tests may render. This material was written on August 3, 1921, and the five cases listed below represent the last five consecutive examinations in which the block designs were used. 1 Kohs, S. C.: The Practicability of the Binet Scale and the Question of the Borderline Case. Bull. No. 3, 1915, Research Dept. Chic. House of Correction, p. 23. 2 Miner, J. B.: “ Deficiency and Delinquency” (Baltimore, Warwick & York, 19x8; 335 p.). 214 INTELLIGENCE MEASUREME: Name Tests Used Date Examined I. Irving T (a) Illinois Examination II, Form i July 28, 1921 (b) Stanford-Binet (c) Kohs Block-designs 2. Edna U (a) Stanford-Binet July 27, 1921 0b) Kohs Ethical Discrimi- nation1 (c) Kohs Block-designs 3* Chas. V (a) Stanford-Binet July 21, 1921 (b) Kohs Block-designs 4- Frank W (a) Stanford-B i n e t (by Miss K. Donald) July 14, 1921 (b) Kohs Block-designs 5- Kenneth X.. (a) Stanford-Binet July 13, 1921 (b) Kohs Block-designs KEY TO ILLUSTRATIVE CASES Case No. i. At the time of the examination Irving was 17 years 10 months old. Born in Minnesota, of American-born parents, German-English descent, reached the seventh grade, now plumber’s helper earning $5 a day, has a small bank savings. Father died little over two years ago, was a lumber piler. Three other children, older, one boy, two girls. Mother has no influence over Irving. Lives in rented two-story house. Home fairly furnished, clean, and orderly. Irving well clothed. History of delinquency may be tabulated as follows: 1 Kohs, S. C.: “An Ethical Discrimination Test.” J. of Delin- quency, 1922, Vol. 7, pp. 1-15. Copies of this test with complete in- structions and scoring material may be secured from the C. H. Stoeltirar Co . t.ot.7 Carroll Ave.. Chicago. Illinois THE RESULTS 215 Date Delinquency Disposition Oct. 13, 1917 Stole sample case containing gums, candies, cookies from auto. Sample case found. Contents gone. Impli- cated with three other boys. Cautioned and released. Sept. 19, 1918 Stole box of crackers from Cracker Co. Irving admitted theft. Claimed he was hungry. Box unopened when found. Ordered to return box, apologize and work to pay damages. Cracker Com- pany satisfied with apology after box was returned. Warned that if he ap- peared in Court again might be sent to one of the institutions. June 9, 1919 Maliciously abusing another boy. Advised to desist and reminded of the State Training School. July 26, 1919 Larceny of automobile. Captured after running machine into telephone pole and front of a grocery. Placed on probation with a Big Brother who arranged for boy’s employment. Damages to be paid. Jan. 7, 1920 Stole two chickens. Three other boys implicated. Severely lectured. Nov. 7, 1920 “Shooting craps” on street. Attention of parent called to this matter. Mar. 10, 1921 School attendance officer reports Ir- ving will not attend evening school. Father dead, mother can do nothing with boy. No specific action taken. July 27, 1921 Larceny of one auto on July 17, con- fessed to another on July 4. On July 18 stripped accessories from two other machines. Disposition now pending. 216 INTELLIGENCE MEASUREMENT On the Illinois Examination II, which the writer has adapted for individual testing, Irving obtained a total score for the general intelligence tests (7) of 67 points. This is equivalent to a mental age of 11 years o months. His I. Q. comes to 69 per cent. On the Stanford-Binet, with a basal year of 9, he obtains an intelligence rating of 12 years 4 months, giving him an I. Q. of 77 per cent. On the block-design test, seven out of thirteen designs attempted are successfully completed, yielding a score of 35 points which is equivalent to a mental age of 10 years n months. His I. Q. here is 68 per cent, within one point of the Illinois Examination. Irving, on the basis of the Binet test, is a borderzone case. On the two other tests he falls below the 70 per cent dividing line. Taking a composite, or an average of the three estimates, his I. Q. becomes 71, still border- zone, which was the intelligence classification finally set down. The complete social analysis of the case is in the process of being made, but the psychological report, at the present stage reads that “if continued social in- capacity is manifested in the future, this boy may be classified as feeble-minded and as such committed to the State Institution for the Feeble-minded.” Case No. 2. Edna is a nice-appearing girl, 15 years and 11 months old at the time of examination, and rather over-developed physically for her age. Born in Oregon of American-born parents, Irish-English descent. Reached the seventh grade. Mother died of tuberculosis soon after Edna was born. Father thought dead, but only recently traced to a small town in Oregon where he is employed as a mill-worker (general labor). Edna has THE RESULTS 217 a brother about four years older, about whom little is known. She first became notorious about a year ago when charges of contributing to the delinquency of a minor were brought against the principal of a small town school which she was attending. The principal was almost lynched at the hands of the inhabitants, although acquitted of the charges by a jury. After this episode she was brought to Portland and placed with an aunt who is rather irresponsible. Excerpts of the report from the Woman’s Protective Division read as follows: “Sat. July 16, Edna was sent to a grocery store at Sts., to make some purchases. D waited on her. She loitered in the store looking at a book and finally D told her she owed him io cents and asked her to come into the back room. She went in and D had relations with her. She says she went to the store between i and 2 and left between 2 and 3. “ She dared not go home so started to walk. On st. she was overtaken by Ed who was driving an automobile. (Ed is a juvenile who has previously been before the Court for immorality.) He asked her where she was going and she replied to Q (a small town approximately 20 miles distant). He offered to take her there; she got into the machine with him, he drove her to Q out Road and had relations with her in the woods. Then took her back to Q at about 10 p.m. “She stayed alone at Hotel, room 6, registered as (fictitious name) and paid 75 cents for her room. She says she had a little money when she left home. “Ed gave her his name and address when he left her. In the morning she started to walk back to Port- land, had no supper or breakfast. She walked all the 218 INTELLIGENCE MEASUREMENT way back to Portland to , arriving there about 3 or 4 Sunday p.m. “George saw her standing on the street corner across from St. He and Ed took her in a Ford for a ride, went out past Road, both boys had rela- tions with her, first Ed, then George. George had rela- tions with her twice at this time. She thinks she was out with the boys about two hours ...” And so the story unravels, involving more boys the farther it goes. The girl was not actively in search of these experiences but seemed a rather obvious mark to the unscrupulous. When this information reached the press it appeared under the following headlines: “GIRL, 15, FOUND IN SHACK, 20 men suspects arrested, but only 5 are held — police are of opinion runaway child is weak-minded — physician takes charge.” After a short period of observation Mrs. Lola G. Bald- win, head of the Woman’s Protective Division, declared the girl utterly irresponsible. By the Stanford-Binet test, with a basal year of 8 years, Edna manifested an intelligence equal to 11 years 5 months. With a life age of 15 years n months her I. Q. is 72 per cent — borderzone. Given the block designs she succeeded in passing only one, the first, of the six designs attempted. Her score on this test amounted to 1 point, this being equivalent to a mental age of 5 years 7 months. This indeed, is far from the girl’s actual intelligence level, but it possesses diagnostic significance, especially in relation to our “borderzone” problem. On the Ethical Discrimination Test the percentage efficiency in each exercise was as follows: THE RESULTS 219 I. Social Relations • 90% 2. Moral Judgment ■ 8o% 3- Proverbs • 6o% 4- Definitions of Moral Terms • 53% 5- Conduct Evaluation • 5o% 6. Moral Problems • 90% Average • 7i% On the basis of tentative norms this average of 71 per cent is equivalent to the performance of about a 12x/i year-old. In the light of this history, her motives, and her general record, the girl was declared feeble-minded, unable because of marked retardation in intelligence to manage herself and her affairs with the ordinary prudence com- mon to other girls of her life age. The further disposition of the case is now pending. Case No. 3. Charles is the duller-looking one of the two boys left with a maternal aunt after the father died five years ago, having been killed by a railroad train, and the mother had been committed to State Institution for the Feeble-minded two and a half years ago. Mrs. M brought Charles to court one day (Dec. 2, 1920), claiming the boy was feeble-minded just like his mother, that she was willing to keep the other boy, but that Charles was a hopeless case and consequently the state should undertake the care of the child. At the time of the first examination Charles was 7 years n months and tested, by the Stanford-Binet, showed an intelligence of 6 years 6 months, his I. Q. being 82 per cent, and classifiable as dull-normal. Although a petition in feeble- mindedness had been duly filed in this case, this was canceled and the boy turned over to the Boys’ and Girls’ 220 INTELLIGENCE MEASUREMENT Aid Society for observation, education and treatment. Charles was born in Portland of German-American parentage, the father only being foreign-born. The child’s report card for three months showed “good” marks in all subjects except “application” for the second month. Charles is affected with ptosis, giving one a poor impression of his intelligence. On April 12, 1921, we unearthed the fact that a quack “psycho-analyst,” had “examined” the boy back in 1918, had adjudged him feeble-minded, a vacancy for the boy had been made at the feeble-minded institution, and in 1919 when the boy was about to be sent, his aunt experienced a change of heart. She claims Charles is unreliable, can remember nothing, frequently fails to come home from school or after being sent upon errands, and that he has been two years in the first grade. There is a sister of Charles’ eleven years old staying with grandparents in eastern Oregon who are very poor. When Mrs. M’s home was visited it was found to be a four-room affair, rather neat. Mr. M was found in bed where he has been confined for many years with articular rheumatism. The sources of income of the M family are distributed as follows: “$20 a month from Mr. M’s lodge, sick-benefit; $30 from the county for the care of Charles and his brother, and the money paid by three men boarders. Of this money $100 must be paid every three months in pay- ment for the purchase of this home. Mrs. M has three daughters, aged 18,16 and 8. The two eldest are in high school and must sleep at a neighbor’s for lack of room. The boarders occupy a tent in the yard. After Charles was at the Boys’ and Girls’ Aid Society for four months, THE RESULTS 221 he was reported by the Superintendent as being feeble- minded and unplaceable. Another mental examination was, therefore, arranged. On July 21, 1921, Charles was again examined. He was now 8 years 6 months and on the Stanford-Binet obtained a mental age of 7 years o months. Again his I. Q. was 82, and was again classi- fiable as dull normal. It was then decided to give him the block-design tests. Although on the basis of life age he should have secured a score of 14 points, and on the basis of mental age his block-design score should have been at least 6 points, he failed to perform any of the designs correctly, in spite of continued explanations and demonstrations. His intelligence age here was below 5 years 3 months, yielding an I. Q. under 62. However, he was sent back to the Aid Society for further observa- tion and treatment. In the meantime his intelligence has been set down as dull normal, but possibly poten- tially feeble-minded. Case 4. Frank W. first came to the attention of the court when a neighbor reported on December 14, 1918, that Frank, n, and his sister of 4 had been left with a maternal grandmother, a widow, the mother having died recently, and the father having deserted, his where- abouts not being known. The family also was reported to the local Associated Charities as being in destitute circumstances. It was learned later that Frank’s father was rather nomadic in tendency, and in 1914 had deserted the family for good after the second child had been born. On September 2, 1919, it was reported to us that the grandmother was abusing and unmercifully beating Frank. On September 8, the grandmother was 222 INTELLIGENCE MEASUREMENT visited. She claimed Frank was unruly and disobedient, that she does punish him, there being no other way of getting along with him; denied most emphatically that she had ever punished him to an extent that might be deemed cruel or excessive. She was found living in a rented home, her income being derived from little sew- ings and from keeping a boarder. For some intangible reasons she has been ostracised by her neighbors. Al- though Frank did not appear quite normal to the visitor, his sister seemed a happy, healthy child, neat, apparently well cared for, and devoted to her grandmother. At the time of this visit Frank was attending the regular schools, was in the 4th grade, and the teachers gave a good report of his conduct in school. Four months later we find Frank in the Etna School (ungraded) with a petition for feeble-mindedness filed by the Public Wel- fare Bureau. He was examined July 14, 1921. His life age was 13 years 4 months, and on the Stanford-Binet he secured a mental age ranking of 8 years 9 months. His I. Q. was 66. On the block-design test, of six designs attempted two were successfully completed, scoring 3 points on the first design and 4 points on the third making a total of 7 points. He was utterly lost beyond the third design. His mental age ranking here was 7 years 3 months, with an I. Q. of 55 per cent. The grandmother admitted that the boy was feeble-minded but was prone to argue about the causation. Disposition of the case is now pending. Case 5. Kenneth X. first came to our attention June 20, 1921, when Miss Ida M. Manley, principal of the Etna School (ungraded) filed a petition in feeble-minded- THE RESULTS 223 ness. This was accompanied by a memorandum which contained the following information. Mother until recently a janitress in one of the schools, father died two years ago, said to have had locomotor ataxia. Ken- neth has been in special class for three years (third grade). Has habit of taking everything loose about the school. Is exceedingly clever in making up stories to cover his guilt. Repeated scoldings, warnings, and punishments have no effect. Kenneth’s mother has had three other children, one died because of premature birth, one was born paralyzed, and the other died at six years of age of a “natural disease,” as the mother put it. With a basal year of six Kenneth obtained a mental age of 8 years io months. His life age at the time of ex- amination was n years 6 months, giving him an I. Q. of 77 per cent, classifiable as borderzone. On the block- design tests, of ten designs attempted only three were successfully completed, and after design six he appeared hopelessly baffled. His total score was n, i point on design i, 5 on design 4, and 5 on 6. This performance is equivalent to an intelligence age of 8 years o months, yielding an I. Q. of 70 per cent. Other elements in the situation made it appear more reasonable to hold up proceedings on the commitment for another year, pend- ing further observation and treatment. The cases cited have not been specially selected, but have been taken in consecutive order. The limitations of space have made it necessary to omit much social and psychological information which is pertinent. The chief object has been to indicate wherein the block- design tests have been of assistance; consequently their 224 INTELLIGENCE MEASUREMENT importance may appear exaggerated from the bare perusal of the material presented. It is expected that the reader will understand the correct proportion of emphasis placed upon block-design performance. In conclusion, the block-design tests, even though it should be granted that they fail to measure intelligence as efficiently as other standard methods, nevertheless are found valid because they assist in the differentiation of the borderzone group, some of whom are normal and some feeble-minded. (10) Percentage Ratios of Agreement and Disagreement with Established Standards of Intelligence In this section an analysis will be attempted to in- dicate in quantitative terms the actual amount of diverg- ence between the mental age and I. Q. estimates of the block-design test and the Binet. (a) The Method of Direct Comparison: Taking Table LXX (p. 176) and analyzing it for agreement and diver- gence of mental ages, the table on p. 225 is obtained. It is apparent that the block-design test is inclined to give somewhat higher mental ages, in general, than the Binet. Interpreted in a slightly different fashion, the following tabular analysis is obtained. Exact correspondence and within i yr. = 53.8% “ “ “ “ 2yrs. =75-9% “ “ “ “ 3yrs. =89.1% “ “ “ “ 4yrs. =93-7% “ “ “ “ 5 yrs. = 98.4% In other words, in practically 90 per cent of the cases examined the two mental ages were the same or showed no difference greater than 3 years in either direction. THE RESULTS 225 Per Cent Exact Corre- SPONDENCE Binet Age Per Cent Higher Binet Age Per Cent Lower i Yr. 2 Yr. 3 Yr. 4 Yr. S Yr. 6 Yr. 7 Yr. 1 Yr. 2 Yr. 3 Yr. 4 Yr. S Yr. 6 Yr. 20 .$ . . 18.0 9-3 55 1.6 2-5 •5 •S IS-3 12.8 7-7 3° 2.2 •S Total —37.9% Total — 41.5% Total 99-9% Mental Age Divergences TABLE LXXXII 226 INTELLIGENCE MEASUREMENT This substantially corroborates the findings discussed under the heading, “The Probable Error of a Block- design Mental Age.” In order to appreciate the true significance of this divergence the discrepancies between two Binet tests of the same individual will be stated. The following has been obtained from Ter man’s table1 showing the agreement between the earlier and later tests of 428 children by the Stanford-Binet. (Correla- tion, r = + .93.) TABLE LXXXIII I. Q. Divergences Per Cent Exact Corre- spondence Second I. Q. Points Higher (%) Second I. Q. Points Lower (%) 5 IO is 20 25 30 35 5 IO is 20 25 30 35 40 45 30.0 . . 25.0 11.8 3-o 1.9 •7 .2 14.2 8.6 2.6 •9 .2 . 2 Total — 42.6% Total — 26.7% Total 99-3% Although the basis of comparison is not entirely equivalent, some idea may be obtained of the reliability of the block-design tests if compared with the discrep- ancies found upon measuring the same individual with the same measuring scale on two different occasions, the I. Q. in this instance being assumed to remain fairly constant. (Although the following observation is some- what aside, it may be of interest to call attention to the fact that the positive discrepancies of I. Q.’s obtained from the second Binet were more than one and one-half 1L. M. Terman: “The Intelligence of School Children,” p. 143 (Table 26). THE RESULTS 227 times as frequent as the lower ones.1 It will be observed that exact correspondence occurs in 30 per cent of the cases, and the other deviations maybe tabulated as follows: Exact correspondence or within 5 I- Q. = 69.2% CC CC CC cc IO I. Q. = 89.6% cc cc CC cc 15 1. Q. = 95-2% cc cc cc cc 20 I. Q. = 98-0% cc cc cc cc 25 I. Q. = 98.9% It should be borne in mind, however, that at different life ages, I. Q. changes of the above magnitudes will possess different equivalent age values. These figures serve as a fairer basis of comparison in determining the discrepancies between I. Q. as deter- mined by the Binet and the block-design tests. (Again the comparison is not a fair one in view of the existing controversy over the constancy of the I. Q. The writer has been unable to find material which would be exactly comparable.) Taking the date of Table LXXII (p. 183) the follow- ing agreement and divergence of I. Q. are found: TABLE LXXXIV I. Q. Divergences Per Cent Exact Cor- respondence 2 Binet I. Q. Points Higher Binet I. Q. Points Lower IO 20 3° 40 SO IO 20 30 4° So 23-5 • • 20.8 9.0 4.6 2-5 •3 18.0 ii.8 5-5 2.7 1.4 Total —37.2% Total — 39.4% Total 100.1% 1 For additional interpretations of this condition see E. A. Doll: “The Growth of Intelligence,” Psychological Monographs, Vol. 20. No. 2. 1921, 130 p., especially Chap. III. s Frequency interval is io I. Q. 228 INTELLIGENCE MEASUREMENT Or presented in another form: Exact correspondence or within io I. Q. = 62.3% ii ii ii u 20 I. Q. = 83-1% ii a a ii 30 I. Q. = 93-2% it a u ii 40 I. Q. = 98-4% A better balance between the per cent of negative and positive divergencies is observable here, and also a greater spread of variability than is the case with I. Q.’s derived from consecutive Binet testings. (b) *.The Method of Critical Ninths: A determination of discrepancy may be obtained by an analysis of a dif- ferent sort. Every table presenting the relation between the frequencies of two variables may be divided into nine parts, Qi and Q3 for both serving as the dividing lines. Qi and Q3 divide any distribution into three portions low, middle, and high. Consequently nine groups are possible, thus: Variable (i) c Low h C Middle is High « Q3 Li H2 (icritical cases) Mx H2 Hi H2 Qs lRIABLE Middle O LiM2 Mx M2 Hi M2 Qi > * o Li L2 Mx L2 HxL2 (critical cases) c h C >3 For two tests which supposedly are expected to meas- ure the same trait, Li H2 and Hi L2 may be regarded as the critical sectors in which as small a proportion as THE RESULTS 229 possible of cases should be found. Every case found within these limits is a clear argument against the validity of a newly devised instrument, when measured against one which has already been established (assuming that the already-established instrument is absolutely reliable). Applying this criterion of validity to the data of Table LXX, the following percentages are obtained: Variable (i) Binet Age Variable (2) Block-design Age Critical Cases Li H2 = o (0%) HxL2= 2 (.5%) Total = 0.5% Correspondence Lx L2 - 61 (16.7%) Mi M2 =129 (35.3%) Hi H2 = 71 (19.4%) Total = 71.4% In order to make these values comprehensible in terms of other correlations, the percentage of critical cases for the Binet and Vocabulary1 and for Army Alpha and Stanford-Binet Age2 will be presented: Variable (1) Binet Vocabulary Variable (2) (631 cases) Binet Age Critical Cases Lx H2 = o Hi L2 = o Total = 0% 1L. M. Terman: “The Intelligence of School Children,” p. 3x0. 2 R. M. Yerkes: “Psychological Examining in the Army,” (Memoirs, Nat. Acad, of Sciences, vol. 15, 1921, 890 p.), p. 621. 230 INTELLIGENCE MEASUREMENT Correspondence Li L2 = 145 (23.0%) Mi M2 = 244 (38.7%) Hx H2 = 113 (17.9%) Total = 79-6% Variable (1) Stantord-Binet Mental Age Variable (2) Alpha Raw Score (653 cases) Critical Cases Li H2 = o Hi La = 1 (.15%) Total = 0.15% Correspondence Li L2 = 104 (15.9%) Mi M2 =273 (41.8%) HiH2= 99 (iS-2%) Total = 72.9% It is apparent that a close correspondence exists be- tween the evaluations of intelligence (in terms of Binet mental age) on the part of the vocabulary test, the army alpha, and the block designs. Finally, the same analysis is presented for Binet I. Q. and Block-design I. Q. (data of Table LXXII, p. 183). Variable (1) Binet I. Q. Variable (2) Block-design I. Q. Critical Cases U H2 = 2 (.5%) Hi L2 = o Total = 0.5% Correspondence Li L2 = 73 (19.9%) Mi M2 = 131 (35.8%) Hi H2 = 51 (13.9%) Total = 69.6% THE RESULTS 231 P. S. /B= Boys Cases |G= Gjfis • • - F. M. Cases Life Age - 9 Yrs. Life Age - 14 Yrs. I. Q. Discrepancies GRAPH 43 Binet I. Q. • Binet I. Q.~ IB. D. I. Q. Bmet I. Q. B. D. I. Q. Binet I. Q. B. D. I. Q. B. D. I. Q. 232 INTELLIGENCE MEASUREMENT (c) Graphic Analysis: For a graphic presentation of discrepancies the life ages of 14 and 9 have been selected — age 14 because this life age had the largest single number of feeble-minded below age 17 (see Table I) and age 9 purely at random. An analysis of Graph 43 indi- cates the existence of a number of conditions: (1) A mild process of compensation is operative, some who have low I. Q. on the Binet, obtain high I. Q. on the block designs and vice versa (especially true of the 9 year-olds); (2) Low Binet I. Q. are often coupled with still lower B. D. I. Q., and high Binet I. Q. are often found in con- junction with still higher B. D. I. Q. (3) The larger proportion, however, manifest little, if any, discrepancy between the two I. Q. It will be observed that the range of I. Q. in the block- design tests is considerably increased. This has its disadvantages, but from a clinical point of view this char- acteristic is a desirable one, because of its bearing upon the differentiation of the inferior and the superior. Summarizing this discussion of discrepancy, it may be stated that although the results of the block-design test do not tally exactly with those of other measures of intel- ligence, nevertheless, agreement is close enough to grant the block designs a fair degree of validity, the instances of disagreement being in themselves sufficiently crucial to require a psychological analysis apart from the tests themselves. This concludes the discussion of validity. A number of criteria have been utilized, each differing in weight and THE RESULTS 233 in general importance. In reality the only effective acid test is the pragmatic one. If the tests will be found to work, that is all that the most critical ones of us demand. The array of evidence just presented seems to indicate not only that the tests measure intelligence, but that this is accomplished with a fair degree of accuracy. On the other hand, one should bear in mind Stern’s caution:1 “Psychological tests must not be overestimated, as if they were complete and automatically operative meas- ures of mind. At most, they are the psychographic minimum that gives us a first orientation concerning individuals about whom nothing else is known, and they are of service to complement and to render comparable and objectively gradable other observations — psycho- logical, pedagogical, medical — not to replace these.” 3. DIAGNOSTIC VALUE OF THE TESTS It has been intimated a number of times by writers of varying degrees of expertness and reliability that an estimate of intelligence based upon the use of a single measuring instrument is inclined to be less accurate than one based upon the application of a number of such diagnostic tools. In fact, a frequent failure upon the part of numerous psycho-clinicists is to disregard other important criteria for the proper diagnosis of intelligence or of mental deficiency and to rest content with the results of a single test, somewhat mechanically evaluated. This is especially true of feeble-mindedness. No diagno- sis of this condition is adequate which has not included 1 “ The Psychological Methods of Testing Intelligence ” (Warwick and York, 1914), p. 12. 234 INTELLIGENCE MEASUREMENT weighing the evidence in other fields than the psycho- logical. Thus a verdict of feeble-mindedness which is not supported by evidence of vocational impotence, of educational failure, of social incompetence, of biological taint, is, except in rare and exceptional instances, quite weak and untenable. The issue also has been raised whether we have not overemphasized the verbalistic tests with the inevitable injustice to those who may be laboring under a language handicap. Without desiring at this point to enter any evidence for or against the reasonableness of this con- tention, other than that already presented in this mono- graph, it does seem wise to utilize tests which measure intelligence through “performance” as well as through “language.” The combined results of an inquiry in both these directions seem to indicate a closer approxi- mation of what is the actual mental age of a subject, than if either is used alone. On the other hand, it is plainly evident that no “per- formance” test yet devised measures intelligence as adequately or with as high a coefficient of efficiency as the Binet or two or three other “language” tests. Of course, the standards upon which our judgments of efficiency have been based may be unsatisfactory, e.g., school progress, teachers’ estimates, school marks, etc. At any rate, looking at the matter from a practical point of view, few, if any, clinical psychologists would be free to abandon our so-called “language” intelligence tests for the exclusive use of “performance” tests in classifying children and in making diagnoses of mental deficiency. At present, performance tests are of chief importance as THE RESULTS 235 corroborative and supplementary sources of information. This probably will hold true for some time to come. 4. SERVICEABILITY In his “Stanford Revision of the Binet-Simon Scale” (Warwick and York, 1917) Terman states,1 that “to be widely serviceable a test should demand only the sim- plest material or apparatus, should require at most but a few minutes of time, and should lend itself well to uni- formity of procedure in application and scoring.” The writer has attempted to satisfy these demands in stand- ardizing the block-design tests. Those who utilize the tests will find after a little practice that there can be but little variation in the findings of two examiners, and that the only chance for difference is in the recording of the number of moves made. The special value of the block-design tests lies in the fact that valid results may be obtained independently of the “language factor.” Neither deafness nor lack of language-understanding should be disqualifications in the proper performance of the test. The block designs may therefore be utilized in the study of racial differences, in determining the mental capacities of the deaf and of those suffering from various other language handicaps. As regards the borderzone problem, it appears that this test will aid in a better differentiation of the group of cases falling in this category. The writer maintains that feeble-mindedness is not an arbitrary statistical designa- tion, but is rather a clearly demarked physiological entity quite distinct from normality, statistical psychologists 1P. iso- 236 INTELLIGENCE MEASUREMENT notwithstanding. Years of experience with this type of defect has fixed the notion in the writer’s mind that feeble-mindedness is indicative not only of mental mal- functioning, but also of physiological mal-functioning possibly of endocrine character. The results of fur- ther research, however, can be the only tests of the truth of one’s statements at this time. CHAPTER VI Supplemental Observations 1. Average Mental Age of Adults 2. Increasing Divergence versus Parallel Progress of Mental Development 3. A Performance Intelligence Scale I. AVERAGE MENTAL AGE OF ADULTS Of importance in interpreting the results of this newly devised mental test is the recently raised question regard- ing the average mental age of adults. The current prac- tice of regarding 16 years as the age when intelligence- maturity is attained, and the age characteristic of the American population at large, has been adhered to in the standardization of the block-design tests and in the interpretation of scores derived therefrom. The results of army testing have thrown some question upon the tenability of this standard, and although previous to the testing in the army criticism of the 16- year criterion emanated from certain quarters,1 no great importance was attached to these attacks, clinical psy- chologists continuing the practice of regarding 16 years as the intelligence of the average adult. The results of army testing, due to the overwhelmingly large numbers examined, are likely to receive greater recognition and 1 See controversy between J. E. W. Wallin and S. C. Kohs in Journal of Amer. Institute of Criminal Law and Criminology, 1916, vol. 6 and 7. 237 238 INTELLIGENCE MEASUREMENT may be regarded by some as unalterably conclusive. The army tests indicated that the average mental age of adults, especially utilizing the figures of Group X, a supposedly random sampling of 653 men, is 13 34 years.1 The attempt will here be made to present reasons why we should exercise caution in accepting this level as average, advising instead the continued use of the 16-year standard until further experimentation has been carried on to decide the issue finally. The reasons for questioning the 1334 estimate will be listed seriatim, and have not been arranged in order of importance but rather as they suggested themselves to the writer. (1) It is advantageous in measuring intelligence to utilize a tool which will not present adaptive difficulties for the person examined. Thus familiarity, previous experience, specialized imagery, the peculiar mechanics of the test itself may make it easier for some to obtain satisfactory scores to whom the technique of the test is adapted, and, on the other hand, more difficult for those to whom the test procedure and its attack are strange and unfamiliar. The army test, together with the con- ditions under which it was taken, in and of itself requires “an adaptation to a new situation” which is quite com- plex. All subjects will not adapt themselves similarly. This condition introduces a spurious factor likely to underweight the performance of those below average in mental ability, with the inevitable result that the general average is reduced. An ideal test of intelligence measures “ability to adapt oneself to a new situation,” but is not 1 R. M. Yerkes: “Psychological Examining in the Army,” Memoirs National Acad, of Sciences, pp. 195, 790. SUPPLEMENTAL OBSERVATIONS 239 itself a matter to which “adaptation” is required. In this respect the army tests may be said to fall short, a correcting formula being necessary to compensate for this “drag” upon sub-average ability, when determining the average capacity of a group examined. (2) A matter deserving serious consideration at this time when group testing has deservedly gained such great popularity, both for analyses of intelligence level and of pedagogical achievement, is what the writer has termed the “ theory of progressive score reductionA tacit assumption generally made in group examining is that ability manifested in a group-test will very closely cor- respond to the same level of ability attained in an in- dividual examination. Regression tables and correlation coefficients are presented as evidence bearing out this contention. A close analysis of the situation will, however, reveal the existence of this condition: Whereas a high score in a reliable group intelligence test is un- questionably indicative of that mental level, because superior scores cannot be obtained by accident or haphazard, the same does not hold true for low scores. One hardly dare state that a low score is ipso facto the inevitable performance of an inferior mentality. Any number of factors may have entered to reduce this score. The chances are that the lower the examinee’s intelligence the greater are the number of these “reducing” factors; and vice versa, the higher the intelligence, the lower the number. The actual situation may be pictured graphi- cally. To make this graph clear, let us assume that we have applied the Binet tests to a large number of subjects and 240 INTELLIGENCE MEASUREMENT we select eleven whose intelligences are respectively, 6, 8, io, 12, 14, 16, 18, 20, 22, 24, 26.1 The median mental age here will be observed to be 16. Let us also suppose that this large group, in which these eleven are included, have been given Army Alpha. It is the writer’s contention that the lower the actual mental ability of the subject examined, to that extent will his score in the group test deviate from his true mental age. According to Graph 44, the subject testing 26 on one test will, supposedly, test exactly the same on the group test. For the other ages. a 24 Binet will possibly measure 23 a 20 Binet will possibly measure 18^ a 16 Binet will possibly measure 13^ a 12 Binet will possibly measure 83^ an 8 Binet will possibly measure 3^ GRAPH 44 Age Reduction Individual Test (Binet) Group TesJ,(Army Alpha)' 'Aver./ Aver. The median performer who on the Binet obtains an intelligence rating of 16, may on the group test, because of this phenomenon of progressive score reduction, ob- tain an intelligence rating of barely 14. (The material 1 The writer is aware that the Stanford-Binet cannot yield such high mental ages except through the predictive use of the I. Q. But for the purposes of this presentation, this deficiency will be overlooked. SUPPLEMENTAL OBSERVATIONS 241 of the graph has been made to conform with the possible condition of the figures obtained from the application of Army Alpha.) It should be noted that the data of Graph 44 would yield a correlation coefficient of + 1.00, yet it would not reveal the increasing inaccuracy of the group intelligence examination with the decrease in the mental ability which it has been devised to measure. (3) It cannot be denied that the Army Alpha over- weights reading ability. Those who have difficulty in reading, or in translating the printed word into more familiar imagery, may be expected to obtain lower scores than on an individual test like the Binet. Evi- dence of this was clearly revealed by the fact that going from Army Alpha to the Combined Scale did not yield the same results in terms of Combined Scale scores, as going from Army Beta to the Combined Scale. In the Beta test (performance) those possessing the mental ability had a more satisfactory opportunity to manifest it than with Alpha. So that in the case of Alpha both the dull normals and inferiors, together with those laboring under language handicaps of whatever form, tended to slide toward the lower end of the frequency distribution. Attention, in this connection, is called to the recent experience of Whipple 1 with three pupils who obtained a mental age from one to three years lower on the National Intelligence Tests than on the Stanford-Binet. Quoting: “These three cases strongly suggest, what would be a priori intelligible, that pupils who have special difficulty 1 G. M. Whipple: “The National Intelligence Tests,” Journal of Educ. Research, 1921, 4:18-31. 242 INTELLIGENCE MEASUREMENT in reading will suffer a decided reduction in mentai age rating by a group intelligence test when compared with their rating by the individual and oral examination of the Binet, though it remains possible that the former rating may be the more significant in predicting school progress.” (P. 31.) (4) The assumption that the draft represented a fair cross-section of the American population is admittedly unwarranted. The frequency tables from which the average intelligence of the American citizen is deduced does not include the figures for officers of all grades. It should also be recalled that thousands of professional men, and those engaged in essential industries were exempted from service and were consequently free of the draft. If we can regard a man more intelligent be- cause he has taken on family responsibilities and has been exempted because he is engaged in caring for those dependent upon him, then this is another very large and important group whose range of ability is not adequately represented in the total results. (5) It is a recognized fact in psychological testing- technique that the physical conditions under which a subject is working may have a very profound effect upon the result achieved. It perhaps will not be ques- tioned that the experimental conditions at the various draft camps were with few exceptions very far from ideal. It was recognized that the failure of the War Department to provide special buildings for psycho- logical examinations proved a very serious handicap, and the facilities which were extended interfered con- siderably with the effectiveness of the work. Among SUPPLEMENTAL OBSERVATIONS 243 the factors which might be expected to affect the results were the following: (a) Examinations followed at varying intervals after inoculation for typhoid, influenza, etc. at various camps; (b) The same degree of variation was characteristic for the time of examination after arrival; (c) In some camps men were examined with a full equipment of apparel including the heavy top-coat, in others men were in their shirt sleeves; (d) Sitting on the floor, tailor-fashion, some on mats, some against posts or the wall for support, others with- out mats or back-supports, may have had some influence upon the results; (e) The use of beaver-boards for hand-rests may have had a varying influence upon efficiency; (f) The preexamining conditions, physical and mental, may possibly have been a factor which should be con- sidered ; (g) The light, air, comfort, and physical properties of the various buildings which served as examination centers were variable quantities which also may have some bearing upon the interpretations of the final averages. It might be well to state before continuing, lest the writer be misunderstood, that these remarks are not made in criticism of the splendid work which was ac- complished by the Psychological Division of the Army, but an attempt is being made to interpret the statistical evidence that the average mental age of adults is 13J4 years. In view of the difficulties and handicaps which were inevitable and insurmountable, we should be 244 INTELLIGENCE MEASUREMENT cautious in carrying over this result to the field of clinical psychology, overturning standards which have been current practice for a good many years. Let us first check these averages for scientific validity. (6) A necessary element in all group testing is “speed.” Experimentation with the army tests has thus far re- vealed that “speed” and“intelligence” are fairly well correlated, and that doubling the time in Army Alpha, for example, does not materially change final rankings. It should be borne in mind, however, that possibly “speed” has been overweighted in the army tests. In fact it is admitted that “assuming that we are dealing with an unselected group, Table LXXIX shows that some limit between double and single time would prob- ably be more suitable.” 1 There is considerable question now regarding the relative values of “speed” versus “power ” tests. There are many who insist that “speed” should be made subordinate to “power.” In view of the possible overemphasis upon speed in the Army Alpha tests, together with the difficulty of discounting it ac- curately, perhaps we had better await further experi- mentation before accepting the intelligence-average as found. (7) For a number of years it has been the practice of clinical psychologists to subdivide the feeble-minded into three groups: idiots, imbeciles, and morons. The mental age limits for these groups are: idiots, from below age one to age two; imbeciles, ages three to seven; and morons, ages eight to twelve. According to the 1 R. M. Yerkes: “Psychological Examining in the United States Army,” p. 420. SUPPLEMENTAL OBSERVATIONS 245 data of the army examinations, if all those testing less than twelve are designated feeble-minded, then 30.3 per cent would be so classified. This, of course, is absurd and unthinkable. We have been ready to admit that approximately the lowest two per cent of the population is mentally unfit to manage itself and its affairs with ordinary prudence. On this basis the army examina- tions indicated that those testing below eight amounted to 2.1 per cent. To reverse our reasoning and to contend that any one with a mental age of eight or over is men- tally fit to manage himself and his affairs with ordinary prudence is to lead to another absurdity belying the facts of our daily experience. We are therefore confronted with two horns of a dilemma, from which there seems no clear-cut escape. If it is true that years is the average mental age of adults, and if it is true that 8 years is the line of demarca- tion for those who are feeble-minded, then we should be prepared to empty our feeble-minded institutions of at least one-fourth of their present populations. We should also proceed immediately to change the I. Q. classifica- tions of intelligence. Instead of an I. Q. of 70 or 75 being indicative of feeble-mindedness (utilizing 16 years as the devisor for adults), the I. Q. of 60 should be adopted (13% years being the highest divisor possible). Similar revisions should be made for the other groups. The moron feeble-minded, then, has been a pure figment of the imagination! The statistical result of the army intelligence tests veritably “knocks the props from under” the customary 2 per cent criterion, the I. Q. of 70 as indicative of feeble-mindedness, it annihilates 246 INTELLIGENCE MEASUREMENT the moron group, and weakens in its entirety the psycho- logical criterion of feeble-mindedness. On the basis of army findings many may be designated “normal” men- tally whose social, pedagogical, industrial, and hereditary history clearly indicates “feeble-mindedness.” Whereas, heretofore, the psychological criterion has been recog- nized as generally the most valuable of them all, it may now become the least significant. Engaged daily and for years in the handling of social misfits, the writer will be slow to abandon established standards until the newer ones are more carefully checked both for reliability and practicability. It may be true that in the army seven to ten-year-olds functioned more or less efficiently, and that comparatively low intelligences on the army tests reported successful living at-large, yet clinical psycho- logists will recall few, if any cases, testing seven to ten years on the Binet who manifest such successful adapta- tions to the complexities of their environment. It is true, of course, that because of the nature of our work we manage to learn only about the unsuccessful morons. Much more satisfactory evidence must be presented, however, to convince one that the successful moron requires no supervision and direction, and actually guides his affairs with ordinary prudence. (8) Because of the constant need for substitutes for the Binet test on account of previous examinations, possible coaching, etc., the writer has had more than two years’ experience applying group tests, such as the Army Alpha, the Haggerty, the Illinois Examination, the National Intelligence Tests, and so on, to individual subjects. It has been amazing to find, after the pre- 247 SUPPLEMENTAL OBSERVATIONS scribed instructions had been read, the frequency with which additional explanations had to be given before the subject could proceed intelligently. There have been occasions where a whole test — for example, the disarranged sentences (true and false), of Army Alpha — had been entirely misunderstood. In this instance all items were underlined “false.” The experimenter then explained the problem more thoroughly, the subject this time placing on record a truer representation of his degree of mental ability. Such procedure in group testing is, of course, impossible. Set directions are pre- scribed. If they are understood, well and good; if not, the matter cannot be helped. No questions can be enter- tained. It is a credit to all the group tests now in use that the directions are remarkably clear and under- standable. But in every group of two hundred, a few will be found who will not quite get the idea, and when averaging results these records give a false weight to the figures. (9) An adequate treatise dealing with the psychology of the crowd would be a valuable asset assisting in the interpretation of the army test results. As yet such an analysis is lacking. We can only speculate upon the nature of an individual’s mental composition when handled merely as one in a large group. If we were to contrast individual psychological examining with group testing, it would not be unfair, perhaps, to state that the circumstance of the crowd is not conducive in all cases to maximum mental effort. There are a host of subtle factors brought into play which it has not yet been possible for scientific psychology to catch hold of. Some 248 INTELLIGENCE MEASUREMENT instincts such as rivalry may make for extraordinary exertion and increased efficiency; on the other hand, there are other counteracting instincts which might just as likely lead to decreased efficiency. In what direction the total balance lies, whether favorable or unfavorable, cannot be dogmatically stated. It is natural to expect that under the best conditions one cannot exceed one’s native ability. On the other hand, native ability may not become manifest under certain restricted conditions. (io) The most important check upon the results of the army testings were the Stanford-Binet ages of 653 draftees from nine different camps. This group has pre- viously been mentioned, and was designated in the army statistics as Group X. The supposition was made that this is a random sampling and is typically representative. There are a number of reasons why this sampling should be questioned. These follow: (a) It is significant that with a possible maximum score of 414 in Army Alpha (weighted) no one of this group received a higher score than 360, and with a possi- ble maximum of 212 (unweighted) no score was higher than 180. (P. 779-780.)* (b) No member of Group X had a schooling record beyond four years of college. It is admitted that the upper range, both for mental ability and for schooling, is not here represented. (P. 779.) (c) Men of foreign birth had been eliminated. (P. 780.) (d) The total group (633) included a number of illiterate men. (p. 781.) 1 These page references are to R. M. Yerkes: “Psychological Exam- ining in the United States Army.” SUPPLEMENTAL OBSERVATIONS 249 (e) Group X failed to include men who were selected as officers or for prospective officer-material. And be- cause of the operation of the draft it was inevitable that many men, because of physical or mental handicaps, were thrown in the discard and never reached a training camp. To what extent a normal distribution is disturbed by these selective processes is a matter still to be deter- mined. (/) This group is admitted defective as a sample on p. 384. “In the first place, the group chosen in any given camp cannot be thought of as typical of the camp; and in the second place, there was the selection involved in the choice of camps.” (g) The attempt was not made to set down first the earmarks of a satisfactory sampling and then adhere closely to the prescription. No effort was made for a proportionate selection, covering the whole range of mental ability. It was felt, rather, that the heterogeneity of the group was a sufficient guarantee of the adequacy of the sampling. (P. 779.) Whatever averages are obtained from Group X must be interpreted with the above facts in mind. (n) The pragmatic test has supported the 16-year criterion. The calculation of the I. Q.’s of adults and the classifications inevitably resulting from the use of this standard have met with rather general satisfaction among clinical psychologists. The utilization of test statistics gathered in the army for the interpretation of mental capacity is well illustrated in the following report1 1 From the Survey of Saturday, Oct. 30, 1920 (Vol. XLV., No. 5), pp. 147-148. 250 INTELLIGENCE MEASUREMENT which is quoted in full. We may naturally expect very strange generalizations such as are here propounded: “Prisoners vs. ‘Men Generally’ “One of the most significant contributions made to the science of penology since Dr. Charles Goring’s monu- mental report on the criminal type, seven years ago, is the recent report of the Mental Survey of Penitentiary Prisoners in Illinois. Dr. Goring’s report completely repudiated the existence of a uniform physical criminal type, and established to be an illusion the doctrine which for a previous quarter of a century had done an incal- culable damage to penal reform. “This new mental survey, under the direction of Dr. Herman Adler, the criminologist, dispels the existence of a uniform mental criminal type. The basis of comparison in the Goring report was the physical characteristics of law-abiding citizens such as college students, soldiers, hospital patients, and the like; the basis of comparison in the Adler report is the result of the group mental tests applied to the United States Draft Army, comprising some 1,700,000 men of draft age from all sections and classes and racial groups in the United States. The report asserts that the result of the army test is an index of the average mental age of the people of this country. “In the Illinois survey the conclusions drawn were on the basis of 1,650 accurate records of prisoners examined by army tests. Four and one-half per cent were in the lowest group — four per cent in the highest. In the penitentiary the inferior group was 16 per cent — in the draft army, 2 5 per cent. The striking fact is there- fore revealed, that the penitentiary has fewer men of inferior development than the draft army, and that it has more men of superior mental development. “The report further shows: Relatively few inferior men, relatively many superior men in the crimes of fraud SUPPLEMENTAL OBSERVATIONS 251 and crimes against property; the reverse in case of sex crimes; the short-termers an average group; the long- termers often either superior or inferior with a larger percentage of inferior. Those prisoners who had served previous terms had half as many inferior types, and nearly twice as many superior types as those prison- ers without previous records of arrest. “Among the reformatory prisoners the comparative results are much the same. The average age is lower and accounts for the existence of fewer superior men in the reformatory than in the draft army. “If the analogy is correct that the American draft army is an index of the country, it is evident from this report that as a group, the prison population is not inferior to men generally.” In contrast to this analysis, in which it is demonstrated practically that penitentiary prisoners in Illinois are superior to men at large, are the findings of Goring,1 of Fernald, Hayes, and Dawley,2 of the NewYork Prison Survey Committee,3 of Miner,4 of Williams,5 and of Healy.6 The testimony of this group cannot very easily be controverted. 1C. Goring: “The English Convict” (abridged edition), London: His Majesty’s Stationery Office, 1919, 275 pp. 2 Mabel R. Fernald, Mary H. S. Hayes, and Almena Dawley: “A Study of Women Delinquents in New York State” (New York, Century Co., 1920, 542 pp.). 3 Report of the Prison Survey Committee. (Albany, N. Y.: J. B. Lyon Co., 1920, 412 pp.) 4J. B. Miner: “Deficiency and Delinquency.” (Baltimore, Warwick and York, 1918, 355 pp.) 6 J. H. Williams: “The Intelligence of the Delinquent Boy,” Jour, of Delinquency. Monograph 1, Jan. 1919, 198 pp. 6William Healy: “The Individual Delinquent” (Boston, Little, Brown & Co., 1915; 830 pp.). 252 INTELLIGENCE MEASUREMENT The following from Goring: “It is clear that the relationship between mental de- fectiveness and the committing of all types of crime, with the exception of some kinds of fraud, is an extremely intimate one. The strength of this bond transcends that of any we have hitherto been able to discover: and it is evident that defective intelligence is one of the primal sources of crime in this country.” (P. 181.) And again, “ Probably the chief source of the high degree of rela- tionship between weak-mindedness and crime resides in the fact that the criminal thing which we call criminality, and which leads to the perpetration of many, if not of most, anti-social offenses to-day, is not inherent wicked- ness, but natural stupidity. At any rate, we need only study the penal records of habitual criminals to realize fully that the one characteristic of the offenses of 90 per cent of the 150,000 persons convicted to prison every year — the one characteristic, apart from their intoler- ableness in a well-ordered society, is the incredible stu- pidity of these offenses.” (Pp. 182-183.) And finally, “ Our final conclusion is that English criminals are selected by a physical condition, and a mental constitu- tion which are independent of each other — that the one significant physical association with criminality is a generally defective physique; and that the one vital mental constitutional factor in the etiology of crime is defective intelligence.” (P. 184.) Next, Fernald, Hayes, and Dawley: (The comparison here was made direct with Group X.) “It is evident from consideration both of the distribu- tion and of the means that the delinquent group is in- ferior mentally to the army group.” (P. 419.) SUPPLEMENTAL OBSERVATIONS 253 “The difference in mental age of 1.6 years (Group X — 13.4 years, New York delinquent women—11.8 years) may be accepted as valid, beyond any reasonable question, since it amounts to more than ten times the standard deviation of the difference.” (P. 420.) And in summary, remembering that these statements refer only to white English-speaking groups, “ the average mental capacity of the delinquent women whom we have examined is lower than that of any groups of non- delinquent adults with regard to whom we have data,” and “ the above statement does not imply a selection of individuals entirely from the lower end of the scale of intelligence for the delinquent group. There is, in fact, an extensive amount of overlapping of the delinquent with the non-delinquent groups.” (P. 433.) And in conclusion, “It is evident from the foregoing statement that our findings are in accord with Goring’s as regards the fact of a difference and its direction. They indicate, however, a slighter degree of difference than he implies.” (P. 434.) Of course, this smaller difference is inevitable in view of the reduction of the standard. These quotations are from the Prison Survey Com- mittee of New York: “A large section of the prison population consists of custodial rather than punitive cases. The prisoner who is mentally or physically unable to cope with the condi- tions of a free society should not be allowed to complete the cycle of commitment, release, and recommitment, and indulge between times in a criminal career as the only means within his knowledge of obtaining a liveli- hood. Dr. Glueck, after a study of 602 cases at Sing Sing Prison, found that 28.1 per cent showed intelligence equivalent to that of the average American child of 254 INTELLIGENCE MEASUREMENT twelve years or under.1 Examinations made in various prisons and reformatories, as shown by the State Prison Commission for 1918, estimated from 15 per cent to 25 per cent of the prison population as segregable on account of mental deficiency. These figures, taken in connection with the fact that the same report states that 87 per cent of the felons admitted to the prisons in 1917 had served previous terms, make obvious the fact that a large per- centage of those who are released are incapable, either from certain mental defects or from lack of training in the institutions, of maintaining themselves in society. It is believed that before any great advance can be made in the training of prisoners the mental deficients must be sorted out, segregated, and dealt with as a separate unit. Elementary, advanced, and industrial education, wage incentives, self-government, and parole measures will be of little avail with this class of prisoners, whose mental limitations prevent them from taking advantage of any privilege or opportunity.” (P. 104.) One is interested to inquire to what extent this general- ization applies to approximately half the American popu- lation, for the data of Group X, if regarded as represen- tative of the country at large, indicates that only 52.7 per cent of American citizens are 13 years mentally or over! And again on p. 114 we find the remark, “From the figures obtained from various penal and correctional institutions, and from the examinations made by the Prison Survey Committee, it is believed that from 8 to 14 per cent of the prisoners, other than those in insane hospitals, are mental defectives requiring institutional care.” And now these remarks of Miner, whose regard for careful statistical analyses is a high guarantee of the soundness of his generalizations: “In the face of the fact 1 Those of Group X under 13 years mentally amounted to 47.2%. Almost twice as many! SUPPLEMENTAL OBSERVATIONS 255 that mental deficiency is undoubtedly the most impor- tant single factor to be considered today in the institu- tional care of delinquents, one hesitates to correct even the most exaggerated impressions as to its importance.” (P. 167.) “ On the basis of our summary of tested delinquents in the last chapter it seems extremely conservative to sup- pose that 10 per cent of the manifest and potential criminals are as deficient mentally as the lowest 1.5 per cent of the general population. Even with this assump- tion, we find that the chances would be 48 out of a hun- dred that a person of this degree of deficiency would be convicted of crime.” (P. 216.) “The most significant fact demonstrated by the corre- lations between juvenile delinquency and deficiency is that there is a positive relationship which is significant in amount. With the maximum estimate the correlation is nearly six times its error. This is the first time that the relationship has actually been calculated in connec- tion with any group of juveniles.” (P. 223.) And in his conclusions, “We have summarized some of the best and most recent investigations in which a notable advance toward solving this problem has been made by means of the correlation method. This has proved to be a new and vigorous force for directing social progress. By no other method have we approached so near the solution of the cause of delinquency. It enables us to restate the problem of criminality as mainly a problem in the treatment of a hereditary criminal dia- thesis, in which mental deficiency is the largest factor.” And then by way of a final word, “Unless the present evidence, however, is outweighed by improved data obtained in the future, the most strategic point for attacking persistent delinquency is through the relation to deficiency, with heredity holding the heights.” (Pp. 244-245.) 256 INTELLIGENCE MEASUREMENT The following are four of the conclusions of Williams: “(2) That the general level of intelligence among delinquent, dependent, and potentially delinquent boys is decidedly lower than that of ordinary children and adults of the same ages. “(3) That feeble-mindedness is much more common among delinquent, dependent, and potentially delinquent boys than in the population as a whole; and that approxi- mately 30 per cent of the delinquent and dependent boys included in this investigation are definitely feeble- minded. “ (4) That low intelligence among delinquent boys is the chief contributing factor in their delinquent conduct. “(5) That any level of intelligence lower than that of the average-normal accounts in part for delinquency, the extent to which it is responsible depending upon the degree of intelligence, which may be best expressed by the intelligence quotient.” (P. 181.) For 1000 young repeated offenders Healy reports “as beyond peradventure feeble-minded, we found about 10 per cent, but the figure will be increased as some of the younger in the lower groups fail to advance with age.” (P. 140.) And again, “The subject of mental defect is of great import in the study of delinquency and its causation. Just what percentage of delinquents are feeble-minded appears to be a matter of perennial interest, but well- founded statistics, even if obtained in particular places, may not be applicable to different situations. There can be no doubt that separate reformatory or prison popula- tions if tested would show from 10 to 30 per cent, or even more, to be feeble-minded.” (P. 447.) “But the gist of the situation is that mental defect forms the largest single cause of delinquency to be found by correlating tendency to offend with characteristics of the offender.” (P. 447.) SUPPLEMENTAL OBSERVATIONS 257 To return to the report in The Survey, in which one is given to understand that the penitentiary prisoners of Illinois are equal to men generally in mental capacity, if not slightly superior. Analyses such as these contra- dict all previous experience, and their cumulative force will bring about a distorted perspective, which may only confound the layman and the prison administrator in the adequate handling of our anti-social and unsocial classes. (i 2) The outstanding advantage of an individual test lies in the fact that a rapport between examiner and examinee may be established. This is of unquestioned value in increasing a subject’s efficiency and in inter- preting the results of any given performance. In an individual examination failures can be explained more adequately, interest, application and distractions can be observed, malaise or other discomforts irritating the subject may be properly discounted. In a group test this is not possible. Your achievement within the forty- five minutes is the measure of your intelligence. No allowances can be made for any disturbing or distracting influences. To what extent the army averages have been reduced because of this inaccuracy cannot be even guessed. Combined with other reducing factors, the surprisingly low average mental age found is, to a certain extent, to be expected. (13) Applying the ‘‘test of common sense” to the i&i standard, although unscientific, it possesses, never- theless, a certain degree of validity. So-called “common sense” is generally a combination of attitudes or points of view based upon long experience, both of the individual and of the group in which an individual finds himself. 258 INTELLIGENCE MEASUREMENT Common sense is opposed to the conception that mental power reaches its maturity at years. Even now when we tell the layman that intelligence maturity is generally reached at 16, he is shockingly surprised. In reality, the whole problem of determining at what age children reach intelligence maturity is still one awaiting solution. It is realized that this objection to the year standard is not a very weighty one, yet common sense should be considered as one among a number of the acid-tests of truth. (14) Numerous factors of personality and temper- ament probably had varying influences upon the result. Such elements as ambition, conscientiousness, obedience, application, interest, were forces of variable manifesta- tion in some manner leaving an impress upon per- formance. The assumption that there was an ultimate balance, excesses discounting deficiencies, is perhaps not warranted in view of the circumstance that one cannot achieve a high score on the basis of any other condition than actual mental ability. (15) Thus far statistical sanction (the normal proba- bility curve) has indicated no error in the 16-year cri- terion. If 13I is the average mental age of adults, shall we find the same normal distribution of mental ages and intelligence quotients with the year cri- terion? Of course, some raise the question why we should expect a normal distribution even with the 16- year criterion. Taking the data of Table 333 (p. 790),1 no mental age 1R. M. Yerkes: “Psychological Examining in the United States Army.” SUPPLEMENTAL OBSERVATIONS 259 of Group X exceeds 19.9 years. That is the result of the Binet examination of 653 men. For the white draft, 93,955 men, Groups I, II and III (group tests) no mental age exceeds 22.9 years. According to the evidence of the Stanford-Binet Test, intelligence of 20 or over should be found with the following relative frequencies: Mental Age I. Q. Interval Frequency in 1000 2o|—2lf 126-135 l6 2i|—23£ I36-X45 2 Unless there is a great reduction in average intelligence (from 16 to 13) with increase of life age, these ratios of mental power (I. Q.) should be found in a correct random sampling of people at large. Actually, the highest I. Q. using as a base does not exceed about 147 for Group X, and for the white draft, Groups I, II and III, it does not exceed about 174. (From data of p. 790.) (16) In order to determine the range of mental ages characteristic of adults we may be compelled to fall back upon some other measuring device than the Binet scale thus far standardized. It is inevitable, for example, that no member of Group X will test above 19.9, for the reason that a perfect performance of all the Stanford- Binet items can yield only a mental age of 19 years. A peculiar idiosyncrasy which the writer has not seen mentioned in the literature is the possibility of a slightly inferior performer obtaining some mental rating out of a possible maximum of 19I/2 years, whereas one who passes all the tests in the whole series successfully 260 INTELLIGENCE MEASUREMENT achieves a maximum of only 19. Thus with a basal age of 14, a subject is confronted with 6 tests in age 16, each having a value of 5 months, total 30 months; and 6 tests in age 18, each having a value of 6 months, total 36 months. The grand total is 66 months,, or 5 years and 6 months above the basal age 14. This would yield a maximum of ig}/2 years. On the other hand, with a basal age of 16, a subject is confronted with only 6 tests, each having a value of 6 months, total 36 months, and the maximum is only 19 years. Until the Binet scale is more effectively extended into the upper ages, our knowledge of the nature and range of mental ability of adults will be dependent upon a certain amount of speculation. (17) On the basis of the army statistics less than 15 per cent of the draftees examined measured over 16 years in intelligence. It is difficult to conceive in the light of the writer’s ten years’ testing experience that 85 per cent of adults examined have been below average and that only 15 per cent have been above average. If memory is not a deceptive servant, experience seems to point toward an average closer to 16 than to i$}4- Whether the experience of other examiners corroborates this impression cannot be determined without a proper questionnaire. (18) The argument may be made that the army averages for intelligence are valid because the exemption of the feeble-minded counterbalances the elimination of the superior men. This is questionable for the reason that only the extremest variety of inferior ability was eliminated, whereas only a fair degree; of superiority SUPPLEMENTAL OBSERVATIONS 261 was both recognizable as a possibility and a stimulus for officership, and in civil life for exemption because of indispensable social service. The chances are that the processes of selection which yielded Groups I, II, III and X favored the selection of those who, on the whole, were somewhat below the average of the population at large. (19) A satisfactory standard of the’ average mental age of adults should include as well statistics gathered from the mental examination of women. These ad- ditional figures would serve both as a balance and as a check upon the averages obtained from the examination of men. (20) Finally, the danger of accepting the army figures on their face value is expressed on p. 7901 as follows: “The former group is large (Groups I, II and III) and representative, but involves an error dependent on the fact that these men were examined by alpha and beta and not by a mental age scale. The second group (Group X) suffers from the fact that it is small and cannot be demonstrated to be representative.” In conclusion, the writer wishes to express again his keen appreciation of the splendid contributions made by the psychologists during the war, regretting that condi- tions made it impossible for him to share in that epoch- making work. The above discussion has been motivated only by a desire to reduce the inevitable difficulties of clinical psychologists, should we hastily accept the 13)4 age standard. Caution is advised until this question 1 R. M. Yerkes: “ Psychological Examining in the United States Army.” 262 INTELLIGENCE MEASUREMENT of the average mental age of adults, now that it has been so forcibly raised, is more satisfactorily settled. In the meantime, the ends of clinical and applied psychology may be more adequately served, and those engaged in the handling of our unsocial and anti-social classes may find themselves functioning more efficiently, by adhering to the 16-year standard, and by making their psychological and clinical deductions on that basis. 2. INCREASING DIVERGENCE VS. PARALLEL PROGRESS OF MENTAL DEVELOPMENT A great deal of effort is being spent at the present time to determine the constancy of the rate of intelligence development (constancy of I. Q.). No new material will be here presented to enlighten this controversy, except to advise the utilization of a more efficient method for studying rate changes. In all of the discussions thus far, use has been made of equally-spaced cross-section paper in order to graph growth and I. Q. changes. This has resulted in greatly hindering clear analysis and, to an extent, has tended toward the development of mis- leading conclusions. A new method for graphing these ratios is recommended. Psychological and educational studies seem to indicate that age and variability are positively correlated. With a given increase in age we observe a corresponding in- crease in variability. But when the nature of this variability has been graphed a number of inaccuracies have inevitably developed. 263 SUPPLEMENTAL OBSERVATIONS To illustrate with concrete examples: In his analysis of the arithmetic abilities of children, Woody1 states, “In the construction of these scales, it has been assumed that achievement in the solution of problems in the fundamental processes is distributed according to the normal surface of frequency. Furthermore, it has been assumed that the variability of any grade from the second to the eighth is equal to that of any other.” (P. 30.) Graph 45 illustrates this hypothesis. 5CH00L GRADE P.E. SCALE GRAPH 45 Relations of Grade Distributions to Each Other in Addition Plotted in somewhat different fashion, Graph 46 is obtained. It will be observed that progress follows parallel lines. Variability does not increase, and pre- sumably, children of low ability in all the grades will manifest the same difference in comparison with those of high ability, throughout. This is one point of view: 1 C. Woody: “Measurements of Some Achievements in Arithmetic.” Teachers College, Columbia University Contributions to Education, No. 80, 1916, 63 pp. 264 INTELLIGENCE MEASUREMENT that there are mental traits which manifest parallel progress with increasing age. On the other hand, we have the view that there is an GRAPH 46 Parallel Progress of Mental Traits Grade increasing divergence of mental traits with increasing age. This is graphically represented by Miner in his discussion of intelligence development.1 (P. 253.) It will be evident from these curves that the bright and dull children deviate more and more from the average with increase of age. To which mode of development does intelligence compare? Are there different endowments at birth pre- senting a normal curve of distribution, this curve being merely reduplicated at higher ages, as in Graph 46; or are there different endowments at birth presenting a 1J. B. Miner: “Deficiency and Delinquency.” SUPPLEMENTAL OBSERVATIONS 265 Permission Warwick & York. Mature Hypothetical Development Curves {Normal Distribution) Increasing Divergence op Mental Traits GRAPH 47 Ages 2-3 Increases Objective Units 266 INTELLIGENCE MEASUREMENT normal curve of distribution, which upon increase of life age becomes more and more flat as in Graph 47? If the I. Q. is constant, then Graph 46 should adequately picture I. Q. distributions at various ages. But if for the brighter children the I. Q. increases, and for the feeble-minded it decreases, Graph 47 would more ade- quately represent the true state of affairs. Studies of rate of development will not proceed toward a clear analysis of the situation until the method of graphic presentation changes from the use of equally- spaced cross-section paper to that of logarithmically- spaced cross-section paper. Graph 49 has been derived from Fig. 10 (p. 75) of Doll’s monograph,1 only the curves for ages 3, 5, 8 and 10 being transcribed. The curves as originally presented are indicated in Graph 48. The outstanding features of difference between the two methods of presen- tation are so obvious that they do not require descrip- tion. It will be apparent in Graph 49 that (1) I. Q. constancy at all intelligence levels, at all life ages, and at all mental ages produces a line possessing a 45 degree angle. (2) If the I. Q. increases, the angle inevitably increases. (3) If the I. Q. decreases, the angle inevitably decreases. (4) These increases and decreases appear in the graph in correct, not distorted ratios. (5) The angle at which growth proceeds is both an index of I. Q. con- stancy as well as a direct expression of rate of growth. By comparing Graph 49 with Graph 48 it will be ob- served that on evenly-spaced cross-section paper various growth curves must be interpreted in terms of the re- 1 E. A. Doll: “The Growth of Intelligence.” 267 SUPPLEMENTAL OBSERVATIONS spective slopes of specific I. Q.’s, each I. Q. rate having a different slope. In Graph 49, however, all slopes, no matter what the I. Q., if indicative of constancy of development, are at a 45-degree angle. On equally- spaced charts uniformity in rate-growth would have to GRAPH 48 Average Growth Curves of Each Mental Age (After Doll) (F. M. Subjects) Mental Age Life Age be represented by different algebraic formulae. This has an important bearing upon the interpretation of com- parative curves. It appears, upon a superficial examina- tion of the four curves of Graph 48, that there is practically little variation between them, the curves for VIII and X being almost exact duplications of the curves for III and V. Yet when VIII and X are com- pared with III and V in Graph 49, no such striking 268 INTELLIGENCE MEASUREMENT GRAPH 49 Mental Age Growth Curves Mental Age(mos.) Life Age (mos.) SUPPLEMENTAL OBSERVATIONS 269 similarity is evident. In Graph 48, curves III and VIII, especially between the ages of 8 to 14 are almost parallel. The actual differences are brought out more definitely in Graph 49, especially for ages 14, 15 and 16. Taking the individual curves, it is more evident in Graph 49 that age X manifests a regular reduction of I. Q. from age 11 to 16; that age VIII also manifests a constant regular reduction of I. Q. somewhat greater than age X; that age V shows a slight increase in rate of growth up to 132 months (age n), then there is a rapid regression, the ratio of which remains the same up to age 16; and that age III manifests only a slight decrease in rate of growth up to 108 months (age 9), then follows a sudden constant rate of regression up to 168 months (age 14), then the reduction takes a rapid increase up to age 16. Reference to Fig. 12 (p. 107) of Doll’s monograph will emphasize again the need for this suggested method for graphing growth curves. In this figure are presented the individual growth curves showing early arrest with consequent I. Q. decreases. All these curves (Cases 9, 17, 16, 48, 64, 98, 134, 164) are practically parallel, and it was necessary to indicate under each curve the different I. Q. values at each life age. The differences of I. Q. at the two ends of each curve are here presented: Case No. I. Q. Range '' Difference 9 25-17 12 17 • • • 38-25 13 16 51-38 13 48 47-37 IO 64 62-46 l6 98 70-46 24 134 91-55 36 164 93-75 18 270 INTELLIGENCE MEASUREMENT On logarithmic cross-section paper these differences would have been more apparent. Graph 50 illustrates, in another fashion, the advan- tages of the ratio graph over the customary method of plotting rate progress. Two curves are here presented, labeled I and II. The two curves run exactly parallel GRAPH 50 I. Q. Fluctuations Intelligence Quotient Sg8ggS8S^§SS 1501 130 - 110 - 100- 90- 80 70 60 50 45-*- I 1_ A B II ii M 1 1 1 1 1 1 1 U 7 8 9 10 11 12 13 14 15 16 9i si n sx zi it on m o Life Age 0 Life Age in (A), yet in (B), where rate is more adequately repre- sented, no such parallel progress is observed. It is a matter of common knowledge that at lower ages, because of the exaggerated significance of small deviations, there is bound to be greater inconstancy. A deviation of 6 months at age 6 will produce a marked change of I. Q. At age 16, however, a fluctuation of that size is relatively insignificant. To what extent this condition accounts for some of the spurious inconstancies at lower SUPPLEMENTAL OBSERVATIONS 271 ages is yet to be determined. It is probable that cross- section paper reversing the divisions, so that at higher ages fluctuations of a given magnitude are granted greater weight, and at lower ages, less weight, may equalize the inevitable discrepancies. One of the important tasks confronting experimental psychologists who are investigating the problem of in- telligence development is to determine the nature of its progress. Do endowments unfold or develop at a uniform rate, or are there increments or decrements, regular or irregular? To answer this question, perhaps a variety of intelligence tests, other than the Binet, may have to be utilized. And the statistical interpretation of the problem will be greatly facilitated by the use of the ratio chart.1 3. A PERFORMANCE INTELLIGENCE SCALE The work of the last few years has contributed con- siderable material on performance intelligence tests. The block designs, it is hoped, will be found to be a practicable addition thereto. Although this test may be utilized as a measure of intelligence by itself, its greatest value, however, may be realized in combination with other performance tests which are capable of incorpora- tion in such a scale. The time is ripe for the development of a performance intelligence scale comparable in construction to the Binet. An especially rich field for data is the monograph 1 Irving Fisher: “The ‘Ratio’ Chart.” Quarterly Publications American Statistical Association, 1917, pp. 577-601. 272 INTELLIGENCE MEASUREMENT dealing with the results of intelligence tests in the army.1 It was not regarded within the province of this piece of research to develop such a scale, the purpose being rather to standardize a new set of tests, discussing therewith numerous allied questions and problems. 1R. M. Yerkes: “Psychological Examining in the Army.” APPENDIX I Grouped Distributions of Ability OUTLINE A. Three Groups a. 6 a b. 5 a c. 12 Q B. Five Groups a. 6 a b. so- C. 12 Q C. Seven Groups a. 6 ••• i i 5 2 9 i XI 4 3 I 8 2 12 . i 2 I 4 3 Total 5 8 IS 17 8 3 I 57 | x—► 3 2 I o I 2 3 y Ability in A Z*2 Zy2 + Zsy - Zsy 23-i2= 23 ig-i2= 19 30 2 2 3 11 • 22 — 44 i6-22= 64 6 6 1 6-32 = 54 io~32 = 90 4 4 Total = 6 Total = 121 Total = 173 6 12 6 9 2 xy = 86 2 5 Total = 92 86 86 \/i2i-\/i73 11 X 13.2 86 = ijrr+-59 292 INTELLIGENCE MEASUREMENT Correlation Method Used in This Monograph TABLE LXXXIX I 2 3 4 5 6 7 Total 6 . . . i 2 2 I 6 3 M 7 • • • 5 i I I 8 2 g 8 . . . 3 5 2 IO I a o . . . 2 6 2 2 1 12 O IO . i i 5 2 9 I •3 ii 4 3 I 8 2 12 . I 2 I 4 3 Total S 8 IS 17 8 3 I 57 T x—> s 3 I I 3 S 7 y Ability in A Zx2 Zy2 + Zxy — Z xy 32-12= 32 I9-i2= I9 50 5 36 16-32 = 144 i6-22= 64 98 12 8-s2 = 200 10-32 — 9p 63 2 1 • 72 = 49 Total = 173 9 6 g Total = 425 6 18 Total = 23 2 10 5 3° 21 Total = 188 Zxy = 165 165 165 i65_ r ~ V425V173 _ 20-6-13-2 ~ 271.9 = + .61 Using Pearson’s longer formula (Formula 2) _ 82.45 _ 82,45 r 57 X 1.36 X 1.74 134-88 = + .61 Note: Utilizing the method suggested by Thorndike (Table 42, in reference above-mentioned), r for Table LVI, p. 145, is + .73; by this method r is reduced to + .71 APPENDIX II 293 The Pearson-Bravais formula for the coefficient of correlation 2 xy r — — n (TxP-y may be converted into the formula 2 xy r = J ===r V2 x2 X 2 y2 in both of which, x — the deviations from the mean of the x's, and y = the deviations from the mean of the y's. When the deviations are calculated from an arbitrary origin in order to keep them integral and facilitate cal- culation, it is customary to make corrections as shown in the formula 2 x'y' n Vl xVl y r = 2* = 2 »"/ , 2 S x'y' “ 1/izw=^fp?^=r' The amount of error involved in the use of the formula may be tested without recalculating by the following correction: (a) For the numerator: S x' X S / n (b) For the denominator: WWW*®} APPENDIX III Elaboration of Sheppard's Table In order to add to the convenience of those utilizing tables of values of the normal probability integral, Sheppard’s Table for Q (or P. E.), presented as Table 45 (p. 200) in Thorndike’s “Mental and Social Measure- ments” (2d edition), and as Table XLVII (p. 116) in Buckingham’s “Spelling Ability,” has been elaborated, giving the straight-line interpolations to one-hundredths P. E. in Table XC following: 296 APPENDIX III 297 X pTe. Per Cent of Cases .OO .01 .02 ■03 .04 ■OS .06 ■07 .08 .09 .00 00.00 0.27 0.54 0.81 1.08 i-35 1.62 1.89 2.15 2.42 .10 2.69 2.96 3-23 3-49 3-76 4-03 4.30 4-57 4-83 5-09 .20 5-36 5.63 5-9° 6.16 6-43 6.70 6.96 7-23 7-49 7.76 •30 8.02 8.28 8.54 8.81 9.07 9-33 9-59 9-85 IO.XI 10.37 40 10.63 10.89 11.15 11.41 11.67 n-93 12.19 12.44 12.70 12.95 •5<> 13.21 13.46 13-71 13-97 14.22 14.47 14.72 14.97 15.21 15.46 .60 IS-7I 15.96 16.21 16.45 16.70 16.95 17.19 17-43 17.68 17.92 .70 18.16 18.40 18.64 18.87 19.11 19-35 19-59 19.82 20.06 20.29 .80 20.53 20.76 20.99 21.22 21.45 21.68 21.91 22.13 22.36 22.58 .QO 22.81 23.03 23-25 23.48 23.70 23.92 24.14 24.35 24-57 24.78 I .OO 25.00 25.21 25.42 25.64 25-85 26.06 26.27 26.47 26.68 26.88 I.IO 27.09 27.29 27.49 27.70 27.90 28.10 28.30 28.49 28.69 28.88 1.20 29.08 29.27 29.46 29.66 29.85 30.04 30-23 30.41 30.60 30.78 1.30 30.97 31.15 31-33 31-52 31.70 31-88 32.05 32.23 32.40 32.58 140 32-75 32.92 3309 33-26 33-43 33.6o 33-76 33-92 34-09 34-25 1.50 3441 34.57 34-73 34.89 35-05 35-21 35.36 35-51 35-67 35-82 1.60 35-97 36.12 36.27 36.41 36.56 36.71 36.85 36.99 37.14 37.28 1.70 3742 37.56 37-70 37.83 37-97 38.11 38.24 38.37 38.50 38.63 1.80 38.76 38.89 39-01 39-14 39.26 39-39 39-51 39.63 39-76 39.88 I.90 40.00 40.1 X 40.23 40.34 40.46 40.57 40.68 40.79 40.91 41.02 2.00 4I.I3 41.24 41-34 41-45 41.55 41.66 41.76 41.86 41.97 42.07 Per Cents of the Normal Frequency Surface Corresponding to Given Values of P. E. (The Median is the Point of Origin of P. E. Values) TABLE XC 298 INTELLIGENCE MEASUREMENT X Per Cent of Cases P. E. .00 .01 .02 .03 .04 •05 ,06 .07 .08 .09 2.10 42.17 42.27 42.36 42.46 42-55 42.65 42.74 42.83 42.93 43.02 2.20 43-n 43.20 43.28 43-37 43-45 43-54 43-62 43-71 43-79 43.88 2.30 43-96 44.04 44.12 44.19 44.27 44-35 44.42 44-50 44-57 44.65 2.40 44.72 44-79 44.86 44-94 45.01 45.08 45-15 45-21 45.28 45-34 2.50 45-41 45-47 45-54 45.60 45-67 45-73 45-79 45-85 45-9° 45-96 2.60 46.02 46.08 46.14 46.19 46.25 46.31 46.36 46.41 46.47 46.52 2.70 46.57 46.62 46.67 46.72 46.77 46.82 46.87 46.91 46.96 47.00 2.80 47-°5 47-09 47.14 47.18 47-23 47.27 47-31 47-35 47.40 47-44 2.QO 47.48 47-52 47-56 47-59 47-63 47.67 47-71 47-74 47.78 47-8i 3 00 47-85 47-88 47.92 47-95 47-99 48.02 48.05 48.08 48.11 48.14 310 48.17 48.20 48.23 48.25 48.28 48.31 48.34 48.37 48.39 48.42 3.20 48.45 48.48 48.50 48.53 48.55 48.58 48.60 48.63 48.65 48.68 3 30 48.70 48.72 48.74 48.77 48.79 48.81 48.83 48.85 48.87 48.89 3 40 48.91 48.93 48.95 48.96 48.98 49.00 49.02 49.04 49-05 49.07 3-50 49.09 49.11 49.12 49.14 49-15 49.17 49.18 49.20 49.21 49-23 3.60 49.24 49-25 49.27 49.28 49-3° 49-31 49-32 49-33 49-35 49-36 3 70 49-37 49-38 49-39 49.41 49.42 49-43 49.44 49-45 49.46 49-47 3.80 49.48 49.49 49-5° 49-51 49-52 49-53 49-54 49-55 49-55 49-56 3 90 49-57 49-58 49-59 49-59 49.60 49.61 49.62 49-63 49-63 49.64 4.00 49-65 49.66 49.66 49.67 49.67 49.68 49.69 49.69 49.70 49.70 4.10 49-71 49.72 49.72 49-73 49-73 49-74 49-75 49-75 49.76 49.76 4.20 49-77 49-77 49.78 49.78 49-79 49-79 49-79 49.80 49.80 49.81 4-30 49.81 49.81 49-82 49.82 49-83 49-83 49-83 49.84 49.84 49-85 4.40 49-85 49-85 49.86 49.86 49.87 49.87 49.87 49.87 49.88 49.88 TABLE XC — Continued APPENDIX III 299 X p7¥. Per Cent of Cases .00 .01 .02 ■03 .04 .05 .06 ■07 .08 .09 4-50 49.88 49.88 49.88 49.89 49.89 49.89 49.89 49.89 49.90 49.90 4.60 49.90 49.90 49.90 49.91 49.91 49.91 49.91 49.91 49.92 49.92 4.70 49.92 49.92 49.92 49-93 49-93 49-93 49-93 49-93 49.94 49.94 4.80 49.94 49.941 49.942 49.944 49-945 49.946 49.947 49.948 49.950 49-951 490 49-952 49-953 49-954 49-955 49.956 49-957 49.958 49-959 49.960 49.961 5.00 49.962 49.963 49.964 49.965 49.966 49.967 49.968 49.969 49.969 49.970 510 49.971 49.972 49.972 49-973 49-973 49.974 49-975 49-975 49.976 49.976 520 49-977 49.978 49.978 49.979 49.979 49.980 49.980 49-98x 49-981 49.982 5-30 49.982 49.982 49.983 49-983 49.984 49.984 49.984 49.985 49.985 40.086 540 49.986 49.986 49.987 49.987 49.988 49.988 49.988 49.989 49.989 49.990 550 49.990 49.990 49-99° 49.991 49.991 49.991 49.991 49.991 49.992 49.992 5-6o 49.992 49.992 49.992 49-993 49-993 49-993 49-993 49-993 49,994 49.994 5-70 49.994 49.994 49.994 49-995 49-995 49-995 49-9951 49.9952 49-9953 49-9954 5 80 49-9955 49-9956 49-9957 49-9958 49-9959 49.9960 49.9961 49.9962 49.9963 49.9964 590 49.9965 49.9966 49.9967 49.9968 49.9969 49.9970 49-9971 49.9972 49-9973 49.9974 TABLE XC — Continued APPENDIX IV Typical Block-Design Records The following records will illustrate the nature of the record blank used in the original standardization of the tests. Twenty designs were utilized, from which seven- teen have been selected in the final revision of the test. This type of record sheet lends itself to a convenient notation of errors in performance and to recording brief notes to assist in the interpretation of the results. 300 APPENDIX IV 301 NO. 26 Examined-Nov. 15.1917-2:15 P. M. 2nd Grade Life Age - 7y. 6m. Wilbur C—N 1 Binet Age-8y. Om. + 2 Time Limit - 11 Seems lost- — still hunting for the right block 3 Time Limit -16 Nothing done — still trying 2 blocks - Placing flat - on side - ver. & hor. 4 Limit -13 — ISIS) ® HI nn b 5 Limit - 12 Power of — analysis seems lacking 6 Limit - 9 0 i BLOCK-DESIGN SCORE = 3 B.D. MENTAL AGE =6 Y. 3 M. 302 INTELLIGENCE MEASUREMENT NO. 263 Examined-Ap. 24,1918-10 A. M. 3-4 Grade Albert R—S Life Age -10y. 4m. 1 21*-7 11 Limit-29 + — I Binet Age- Ibb] lly'4m' 2 1'19*-12 12 Limit-34 (5'0*-36; not yet O.K ) + — Had O. K. onee, then destroyed 3 44*-9 13 Limit - 31 + (BLOCK-DESIGN - [R R R| \SCORE=46 rrH1 ] B.D.M.A. = 1 1 4 1'5*-11 | 11Y. 10M. 14 3'54*-41 + + 6 49*-ll 15 Limit - 29 6 33*-10 16 Limit - 49 (4'13*-52; O.K.) + i <+> 7 2'17*-30 17 2'48*-30 + + 8 Limit-21 18 Limit - 47 “ 2 “ Res^l \ this O.K. I 9 2'8*-20 19 Limit-48 (S: “The |\R\W Picture is -f- — so small & pff R \| there are so many blocks, - It gits 10 1'58*-18 20 Limit - 42 you stuck") + 9 2'8'-20 APPENDIX IV 303 NO. 176 Examined-Ap. 2,1918-9 A. M. 4B Grade Life Age - 9y. 2m. James B—H 1 22'-8 Binet Age-8Y. 10M. + NOTE: Has set something like these at home. 2 32*-4 Larger eize, but not same colors. + 3 46*-10 + BLOCK-DESIGN SCORE = 16 + B.D. MENTAL AGE = 8 Y. 9 M. 5 1'34*-15 + 6 Limit - 16 7 Limit - 30 S: “I don’t see how — 1/bSI J you get these yellow ones on the side here.” 8 Limit - 20 Later - fll (w)Rr Wy\ [r|w \ 9 Limit - 16 Later -v " FW \ A 10 Rest O.K. SUBJECT-INDEX Abbreviated Army Performance Test, 157 Ability, grouped distributions of, 273 f. native, 248 “spread” of, 193 Absolute standard, 180 Abstraction, 13 Acceleration, 49 f. Adaptation, n, 32, 168 f., 174, 238 f. Adaptive difficulties, 238 Adolescence, 13,20 Adulthood, 13 Adults, mental age of, 237 f. Age-grade distribution, 39 f. Age-progress analysis, 39 f. Age standardization, 104 f. Ambition, 258 Analogies, 16 Analysis, 6 f., 12 f., 20 f., 26 f., 170 f. defined, 7 Analyst, 20 Analytic activity, 12 f., 18, 171, 175 tendency, 19 type, 21 Analytic-synthetic power, 28, 126 Analyzing ability, 23 Anatomists, 28 Animal discrimination, 30 learning, 23 psychology, 21 Animals, 22, 24 f. Anti-social classes, 257 Aphasias, 26 Application, 258 Arithmetic, 63, 89 f., 190 f. Army Alpha (see Military Test), 157, 246 Army Beta, 157 tests (see Military Tests), 138, 238 f. Assimilating, 18 Assimilation, 7, 11 f. Assimilative type, 21 Associated Charities, 221 Association, 23 f., 173 of ideas, 4, 11 f. Associationist school, 3 Attention, 22 f., 174 Auto-criticism, 174 Average man, 85 Behavior habit, 23 Behaviorist, 9 Bias, 144 Binet scale, 16, 41 f., 68, 78 f., 157, 168, 205 f. accuracy, 118 Birthplace, 39 f., 58 Blending, 7, 12 Block design records, 300 f. test, 39 f. Blocks, 64 f. Borderzone case, 187, 210 f., 235 Boys’ and Girls’ Aid Society, 220 Buckingham spelling test, 72 Business men, 198 Chance, 85 f. Childhood, 13 Chinese, 158 Choice, 22 Chronological age, 25 norms, 121 f. Clinical differentiation, 210 f. psychology, 210 f. Combination, 12 Combinative ability, 7, 10, 26, 305 306 SUBJECT-INDEX Combining, 175 “Common-sense check, 187 test of, 257 Comparing, 171, 175 Comparison, 7, 12 f. Completing, 175 Completion, 10, 12 Composite norms, 112 f. Concepts, 4, 14 Conceptual thinking, 15 Conduct evaluation, 219 Conscientiousness, 258 Consciousness, 7 f. of end, 175 Consistency, 156, 204 f. Construction Test A and B, 157 Constructive activity, 12 Convict, the English, 251 Correlation, 10, 68, 143 f., 180 f. comparisons, 157 f. formulae, 100 method revised, 289 f. Correlational analysis, 281 Cortex integrity, 31 Cortical ablations, 31 Cosmic hypothesis, 171 Crime causes, 252 f. Criminal diathesis, 255 habitual, 252 type, 250 Critical ninths, method of, 228 f. Criticising, 175 Crowd psychology, 247 Cube Construction Test, 157 Cube Imitation Test, 157 Deaf, 235 Deciding, 175 Deduction, 12 Defective intelligence, 252 Defectiveness, 169 Definitions of moral terms, 219 Deliberating, 175 Delinquency, 169, 198 Delinquents, children, 251 potential, 256 women, 251, 253 Department, 63 Design eliminations, 161 f. Designs, 65 f. Desire, 22 Diagnostic accuracy, 179 criteria, 142, 176 f. efficiency, 164, 200, 233 f. syllabus, 211 tools, 143 Differential psychology, 80 Differentiation, 7, 12 Digit-Symbol Test, 157 Direct comparison, method of, 224 f. Disarranged sentences, 247 Discrimination, 7, 12 f., 17, 22 f., 171, 175 Discriminative type, 21 Dissociation, 25 Drawing, 18, 26, 63, 190 f. Economic demand, 273 f., 286 Education, 26, 169 Educational statisticians, 100 statistics, 78 treatment, 177 Electronic theory, 171 Emotion, 8 Endocrines, 236 Endowment 158, 190, 264 f. Epistemology, 5 Equal units scale, 84 f. Ethical Discrimination Test, 214 f. Etna School, 222 Evolution, doctrine of, 171 Experience, 169 Experimentation, 17 Faculties, 27 Faculty psychology, 173 Fatigue, 22 Fear, 22 Feeble-minded, 19, 28, 173, 176, 179, 181 f., 185, 196, 199, 208 f. Feeble-mindedness defined, 209, 235 f- Ferguson Form Boards, 157 Final norms, 166 f. test revision, 161 f. Foot, length of, 287 Foreign born, 51, 158 Form Board ability, 157 SUBJECT-INDEX 307 Form Board test, 157 “Fountain of Youth,” 187 Functional efficiency, 182 Functionalist, 9 Fusion, 7, nf. Gaussian curve, 287 Generalizing abstraction, 2 Genetic psychology, 21, 25 Genius, 17 Geography, 26, 63 Germinal determiners, 22 Glover, 287 Graphic functions, 18 Graphic presentation of norms, 126 f. Grip, 92 f. Group differentiation, 151 Group testing, 137 f., 195 vs. individual testing, 247 Grouped measures of variability, 58, 287 f. Habit, 8, 22 Haggerty Intelligence Examina- tion, 137 f. Hand length, 287 “Hand” subjects, 191 Hatter, 287 Head circumference, 287 Height, 81 f., 88, 175 Heredity, theory of, 171 Hierarchies of mental functioning, 5 f., 10, 19, 29, 170 Higher animals, 22 Higher thought, 8 History, 63 Hoboes, 198 Home conditions, 39 f., 58 f. Household arts, 63, 190 f. Human traits, 80 f. Ideas, 8 Ideation, 170 Ideational activity, 15 Idiots, 244 f. Illinois Examination, 214 f., 246 Illinois Prison Survey, 250 Illiterates, 76 f. Imagery, 26 Images, 8, 26 Imagination, 4, 173 Imaginative-synthetic period, 20 Imbeciles, 244 f. Indiana Survey Tests, 158 Individual differences, 16 f., 80, 84, 169, 182 Induction, 12 Industrial applications, 169 education, 254 problems, 288 Inferior endowment, 158 Information, 169 Innate ideas, 4 Instincts, 248 Integration, 7 f., 11, 29 f. Integrative function, nervous sys- tem, 29 Intellectual behavior, 172 Intelligence, 10, 16, 22, 24, 28, 32, 168 f. defined, 168 f. distribution, 89, 193 maturity, 258 of women, 261 quotient, 176 f. constancy, 266 f. reduction, 269 ratios, 179 Interest, 258 Interpolation, 94 Inter-test correlations, 158 Introspection, 7, 8 Introspective evidence, 166, 172 Invention, 171 Inventors, 16 Italians, 158 Japanese, 158 Judging, 175 Judgment, 4, 8, 170 f., 173 Knowledge, 6 “ Kombinationsfdhigkeit, ”170 “ Kombinationsgabe,” 168 “ Kombinations-methode,” 103 Language, 63, 190 f. expression, 192, 201 factor, 180, 191, 195, 202, 235 308 SUBJECT-INDEX Language, handicapped, 158, 235 symbols, 191 vs. performance, 192 f., 234 f. Learning, 8, 23 Life ages, 39 f. Linear projection method, 98 f. Linguistic facility, 179 Logarithmic graphs, 268 f. Loquacious “types,” 199 Lower organisms, 30 Malaise, 257 Manikin and Feature Profile Test, J57 Manipulation, 175 Manual training, 63, 190 f. Mare and Foal Test, 157 Mayfield children, 39 f. Maze Test, 157 Meanings, 12 f., 25 Measuring rods, 172 Mechanical ingenuity, 126 Memory, 4, n, 22, 26, 173 Menlo Park children, 39 f. Mental ability, 10 age equivalents, 73 norms, 105 f. of adults, 237 f. ages, 41 f. true, 179 capacities, 78 correlation, 22 deficiency (see feebleminded), 209 development, 7, 262 f. rate of, 266 f. diagnosis, 179 f. dynamics, 5 endowment, 9, 25 evolution, 22 “functions,” 173, 204 growth, 175 curves, 267 f. rate changes, 262 f. hierarchies, 5 f., 10, 19, 29, 170 initiative, n power, 258 synthesis, 19 ] traits, 87 increasing divergence of, 264 . parallel progress of, 264 f. Mentartraits, types, 20 Metameric nervous system, 29 Metazoa, 28 Method of, ranks, 81 f. scoring, 69 f. Military Test (see Army Tests), 173, 195 f. “Mind” subjects, 191 Moral, judgment, 219 problems, 219 Moron, 24, 244 f. Morons, successful and unsuccess- ful, 246 Multicellular organisms, 28 Music, 63 National Intelligence Tests, 241, 246 Nationality, 39 f., 54, 58 Nature study, 63 Nerve cell properties, 29 Nervous, protoplasm, 27 system, 10, 28 f. tissue, 13 Neurologists, 28 Neuron, 30 New York, Prison Commission, 254 Prison Survey, 251 Norm, discrepancies, 121 setting, 137 Normal, curve fetish, 100 distribution curve, 209, 263 f. probability, 173 f., 193 f. probability curve, 85 f., 91 f., 99, 258 f. Norms, 54, 71 f. Obedience, 258 Offenders, repeated, 256 Ogive, 81 f. Original tendencies, 65 Otis Tests, 158 Over-refining, 100, 139 Pain, 22 Palo Alto children, 39 f. Pantomime, 75 Parole measures, 254 Patience Test, 174 SUBJECT-INDEX 309 Pearson-Bravais formula, 292 Pedagogical, implications, 25 progress, 78 Penitentiary prisoners, 250 Percentile, method, 80 f. technique, 92 f. Perception, 8, n f., 22,25, 170, *73 Performance, 191, 234 f. intelligence scale, 271 test, 179 vs. language, 192 f., 234 f. Periodic Law, 171 Personal opinion, 197 Personality, 258 P. E., scale method, 99 f. standardization, 130 f. Physical traits, 87 Physiological set, 25 Picture, Arrangement Test, 157 Completion Test, 157 Pintner’s Non-Language Group- Test, 158 Pleasure, 22 Poets, 16 Point scale method, 98 f. Porteus Maze Tests, 157 Portuguese, 158 Power vs. speed tests, 244 f. Practical geniuses, 16 Pragmatic test, 101, 249 Predicting school progress, 242 Pressey Tests, 158 Prison population, 251 Prisoners, 198 vs. men generally, 250 f. Probability, 85 f. Probable error, 173, 204 f. Problem solution, 168 Prognostic diagnoses, 177 Progressive score reduction, theory of, 239 f. Protoplasm, 29 Protozoa, 22, 28 Proverbs, 219 Psychical centers, 27 Psycho-clinician, 177, 211 Psychological, profile, 80 criterion, 246 f. Psychology, defined, 8 Public Welfare Bureau, 222 Qualitative differences, 81 Quantitative differences, 81 Quartile deviation, 94 Questionnaire, 39 f., 61 f. Race differences, 6, 54, 235 Rapport, 257 Ratio chart, 271 Reading, 63, 190 f. ability, 241 f. quotients, 193 Reasoning, 5, 8, 170, 173 Record sheet, 300 f. “Reducing” factors, 239 Reflex, 8 Reformatory prisoners, 251 Reproducing Designs Test, 157 Retardation, 49 f. Rising increments, 175 Rivalry, 248 Sampling, 121, 126, 248 f. Scale making, 78 f. Scattering, 156, 163 School, marks, 188, 273 f. range of, 286 f. progress, 56 f. standing, 190 f. training, 189 Schooling, 10 Science, 63 Scientific men, 16, 171 Score, card, 69 f. values, 73 inconsistent, 182 variability, 198 Scribbling, 18 Seguin Form Board, 157 Selecting, 18 Self-criticism, 18 Self-government, 254 Senescence, 13 Sensation, 8, 173 Sensations, nature of, 4 f. Sense organs, 28 Sensory capacities, 27 Serviceability, 235 f. Sex differences, 39 f., 118 f., 125 f., 147, 150 f., 165 f., 190 f. explanation, 120, 166 310 SUBJECT-INDEX Sheppard’s Tables, 130 elaboration, 296 f. Ship Test, 157 Shirt manufacturer, 287 Shoe manufacturer, 287 Silent, areas, 31 “type,” 199 Similarity, 24 Sing Sing prisoners, 253 Social, class, 39 f., 58 f. relations, 219 treatment, 177 worker, 212 f. Sonoma State Home, 41 f., 181 Specialized capacities, 195, 204 Speed vs. power tests, 244 f. Spelling, 63, 99 Standard deviation, 94 Standardization, 54, 64, 102 f. bias, 1x2 technique, 78 f., 135 technique vs. number, 54 Stanford-Binet Test, 157 Statistical fallacies, 80 f., 137 f. Structuralist, 8 Superior endowment, 158 Supplementary information, 179 Syllogistic reasoning, 169 Symbols, 25 Synthesis, 5 f., 9, 12 f., 18 f., 22 f., 29, 32, 170 f. defined, 7 Synthesist, 20 Synthesizing ability, 10, 168 Synthetic activity, 13 incapacity, 18 type, 21 Synthetic-analytic incapacity, 25 tendency, 12, 25 Teachers’ estimates, 39 f., 58 f. judgments, 187 Temperament, 258 Terminal nuclei, 31 Test, compensation, 179 correspondence, 184 criteria, 79 material, 64 f. penalties, 155 scores, range of, 286 f. Test, weighting, 138 f. Testing psychological tests, 273 f., 287 f. Tests, directions, 74 f. Thalamus, 31 Thinkers, 171 Thinking, 11 Thought, 4, 24 Thurstone Tests, 158 Time, 68 f. and move norms, 142 f. and moves, 99 f. limits, 69 Torso, length of, 287 Tossing pennies, 85 f. Trabue language tests, 41 f., 68, 72, 99, 173, I9S f- Transmutation tables, 100 Trial and error, 23 True-false test, 247 True mental age, 179 Types, 13, 20 f. Unsocial classes, 257 Validity, 172 f. Variability, 175 f-, 201, 204 f. 263 f., 287 f. Verbal expression, 182 Verbalistic tests, 234 f. Vineland Training School, 41 f., 181 Vocabulary, 173, 195 f. Vorticella, 28 Wage incentives, 254 Weight, 175 Weighting moves, 100 f. time, 100 f. Will, 8 Woman’s Protective Division, 217 Women, intelligence of, 261 Woody Arithmetic Test, 73, 99 Work capacity, 182 Writing, 63 Year scale, 127 f. method, 78 f. Yerkes-Bridges Point Scale, 84 Zero points, 84 AUTHOR-INDEX Adler, H. A., 250 Bacon, 3, 4 Bain, 16 Baldwin, B. T., 88 Baldwin, Lola G., 218 Bartlett, F. C., 33 Bergson, 33 Binet, A., 16, 168, 173 f. Bolton, J. S., 33 Book, W. F., 33 Boring, E. G., 87, 135, 209 Bridges, J. W., 98 Buckingham, B. R., 72, 99, 130, 139, 208, 296 Cabot, R. C., 209 Claparede, Ed., 81 Clement, J. A., 158 Coover, J. E., 290 Dawley, Almena, 251 Descartes, 3, 4 Doll, E. A., 83, 179, 227, 266, 267, 269 Duprat, L., 33 Ebbinghaus, 103, 168, 170 Ferguson, G. O. Jr., 157 Fernald, Mabel R., 251 Fichte, s Fischer, C. R., 83 Fisher, Irving, 271 Fisher, Sara C., 24, 33 Franz, S. I., 31 f., 33 Galton, F., 81 Gauss, 85, 87 Glueck, B., 253 Goring, C., 250, 251 Gregor, A., 33 Haggerty, M. E., 137, 139 Hardwick, Rose S., 98 Hayes, Mary H. S., 251 Healy, W., 103, 157, 251 Hegel, s Herbart, 5 Hobbes, 3, 4 Hobhouse, L. T., 10, 14, 22, 24 f., 33 Hume, 4 James, W., 14, 16 f., 23, 26 f. 33 Jennings, H. S., 22, 28 f., 33 Judd, C. H., 8, 13, 34 Kant, 5 f. Kelley, T. L., 79 Kite, E. S., 174 Knox, H. A., 103 Kohs, S. C., 80, 205, 213, 214, 237 Ladd, G. T., 12, 16, 22 f., 31, 34 Laplace, 85, 87 Leibniz, 4 Locke, John, 4 Mach, E., 17, 32, 34 Manley, Ida M., 222 Mateer, Florence, 179 Maudsley, 21 McCall, W. A., 193 Merriman, M., 210 Meumann, E., 13, 18 f., 21, 26, 34, 168, 170 Meynert, 31 Miner, J. B., 80, 213, 251, 264 Morat, J. P., 31, 34 Ordahl, Geo., 181 Otis, A., S., 79, 99, 158 311 312 AUTHOR-INDEX Parker, B., 81 Paterson, D. G., 54, 83, 98, 104 Pearson, K., 289, 292 Pillsbury, W. B., 34 Pintner, R., 54, 83, 84, 98, 103, 104, 158 Porteus, S. D., 157 Pressey, S. L., 158 Quetelet, 85 Reamer, Jeanette C., 84 Ribot, Th., 34 Rignano, Eug., 20 f., 34 Ross., Eliz. L. S., 157 Rossolimo, G., 80 Royce, J., 8, n, 25 f., 34 Rugg., H. O., 275, 286 Schelling, 5 Schopenhauer, 5 Sheppard, 208 Sherrington, C. S., 29 f., 31, 34 Smedley, F. W., 81, 83, 92 f. Spinoza,4 Starch, D., 89, 286 Stern, W., 168, 233 Stout, G. F., 15, 34 Tashiro, 22 Terman, L. M., 16, 51, 89, 168, 174, 196, 197 f., 205, 226 229, 235, 287 Thorndike, E. L., 13, 25, 35, 99, 208, 289, 292, 296 Thurstone, L. L., 158 Titchener, E. B., 12, 34 Trabue, M. R., 72, 99, 130, 139 Wallin, J. E. W., 237 Watson, J. B., 35 Whipple, G. M., 241 Williams, J. H., 251 Woodworth, R. S., 12, 16, 22 f., 31* 34 Woody, C., 73, 89, 99, 130, 139, 263 Woolley, H. T., 83 Wundt, W., 27, 34 Yerkes, R. M., 98, 157, 229, 238, 244, 248 f., 272 Yoakum, C. S., 157 Yule, G. U., 87 Ziehen, Th., 35, 168, 170