Digitized by the Internet Archive in 2019 with funding from Princeton Theological Seminary Library / https://archive.org/details/definitionofinteOOstoc_O ri, PSYCHOLOGICAL REVIEW PUBLICATIONS Wholt No. 137 1921 Psychological Monographs EDITED BY JAMES ROWLAND ANGELL, New Haven, Conn. HOWARD C. WARREN, Princeton University ( Review ) JOHN B. WATSON, New York (/. of Exp. Psychol.) SHEPHERD I. FRANZ, Govt. Hosp. for Insane ( Bulletin ) and MADISON BENTLEY, University of Illinois {Index) The Definition of Intelligence in Re¬ lation to Modern Methods of Mental Measurement / BY J. LEROY STOCKTON, Ph.D. Vice President and Head of the Education Department, State Teachers’ College, Santa Barbara, California PSYCHOLOGICAL REVIEW COMPANY PRINCETON, N. J. and LANCASTER, PA. Aoents: G. E. STECHERT & CO., London (2 Star Yard, Carey St., W. C.) Paris (16 rue de Conde) TABLE OF CONTENTS PAGE Introduction . i I. Necessity for establishing a clear psychological setting for the problem of intelligence . I II. Recognition of types of research . 2 III. Relation of hypothesis to research . 3 IV. The objectives of the thesis as guided by the consid¬ erations mentioned above . 4 Chapter I. Factors in psychological setting for the problem of intelligence . 5 I. Psychological views of the existence and function of soul, consciousness, mind, mental states . 5 II. The modern theory of a unitary mind . 10 Chapter II. Current views of adaptation and mind in rela¬ tion to intelligence . 13 I. The confusion which these terms present . 13 II. Types of adaptation in relation to mind and intelli¬ gence . 14 A. Adaptation in the inorganic world . 14 B. Adaptation in the organic world . 15 1. Primary mechanical types . 15 a. Tropic adaptation . 15 b. Reflex and instinctive adaptation . 15 c. Modified instinctive adaptation . 17 d. Associative adaptation . 17 • • • m IV CONTENTS 2. Purposive type . 18 a. Intentional adaptation . 18 3. Secondary mechanical type . 21 a. Reproductive (habitual) adaptation... 21 III. The definition of intelligence . 22 IV. Summary of Chapter I . 22 Chapter III. Types of studies in the quantitative study of intelligence . 24 I. Measures, not of intelligence, but of factors found to to be correlated with intelligence . 24 A. Correlation of physical traits with intelligence 24 B. Correlation of mental traits with intelligence. . 25 II. Real measures of intelligence . 26 A. Measures of mechanically controlled intelligence 26 1. Original types (unlearned) . 26 2. Learned types . 27 B. Measures of intentionally controlled intelligence 27 C. Measures of reproductive intelligence . 28 Chapter IV. The fundamental nature of intentional adapta¬ tion . 30 I. The “common factor” in intelligence . 30 II. Existing evidences that purposive intelligence is condi¬ tioned by levels based upon an analysis of mind . 34 1. The generally accepted idea that the abstract is “harder” than the concrete . 34 2. The popular, but contradictory, conception that pupils considered dull because they fail in abstract subjects, prove their intelligence by success in concrete subjects . 34 3. Courses of study in institutions for the feebleminded . 35 4. Clinical descriptions of feebleminded per¬ sons . 35 5. Evidence drawn from the construction and the application of certain intelligence tests 37 CONTENTS v a. Illustrations from the Binet tests . 37 b. Illustrations from the De Sanctis tests 38 c. Illustrations from material used by Pint- ner and Patterson in “A Scale of Per¬ formance Tests” . 39 d. Illustration from performance test ma¬ terial developed by Healy . 51 e. Illustrations from studies directed toward the determination of the type of mental function possessed by the feeble¬ minded . 52 f. Illustration from success and failure in abstract and concrete subjects of in¬ struction . 54 Chapter V. The fundamental nature of intentional adapta¬ tion, continued . 58 I. Original quantitative studies . 58 1. In upper school grades . 58 2. In lower school grades . 83 II. Conclusions . 83 Chapter VI. Modern methods of mental measurement . 93 I. The evolution of modern methods . 93 1. A summation of modern tendencies . 93 2. Some general side lights on the development of the modern view . 98 3. Certain minor and major views and studies in confirmation of the existence of a com¬ mon factor in intelligence . 99 II. Possible results of the theory upon modern methods of mental measurement . 102 1. Emphasis upon the value of the language test . 103 2. Tendency to the development of more diag¬ nostic scales of intelligence based upon the VI CONTENTS separate scaling of qualitative differences in the common factor . 103 3. Increased tendency to speculate upon the problem as to whether the development of intelligence ceases soon after adolescence. .105 III. Summary . 107 Typical General References . 109 THE DEFINITION OF INTELLIGENCE IN RELATION TO MODERN METHODS OF MENTAL MEASUREMENT. INTRODUCTION I. Necessity for Establishing a Clear Psychological Setting for the Problem of Intelligence. Probably all will agree that the problem of intelligence belongs in psychology. Naturally, therefore, one would at first thought feel justified in discussing intelligence in terms of mind, con¬ sciousness, and other popularly used psychological terms. There have been times in the history of psychology when this could have been done without raising any question; but even minor excur¬ sions into modern psychology show that the leaders in that field are fundamentally divided by different concepts and terminolo¬ gies. They do not agree as to what mind is. They do not even agree as to whether psychology should assume the existence of mind, or, if it exists, whether psychology should make any at¬ tempt to determine its nature. Hence the student of intelligence is forced to review current psychological theories and to decide as to the attitude which he, himself, shall take. Otherwise any conclusions to which he may come, and any arguments which he may base upon the conclu¬ sions, are likely to prove abortive, due to a mere misunder¬ standing of terms. The situation is similar to that raised by the ancient dispute as to whether there would be any sound at Niagara if there were no ear there to hear it. The argument must result in endless de¬ bate unless one stops to ask whether sound is to be defined in 2 JAMES LEROY STOCKTON terms of physics or in terms of psychology. This illustration merely points the observation that since the intelligence problem is at bottom a psychological problem, any attempt to deal with it constructively must use psychological terms with carefully con¬ sidered and defined meanings. Thus the later argument can be saved from becoming hopelessly at cross purposes. Two sources of confusion in modern psychological terminol¬ ogy are (i) the term mind or consciousness, and (2) faculties, or functions, of mind. It is desirable that the points of view concerning these be carefully discriminated, and definite ones selected. This is not to be done with the idea of settling the matter once for all; but rather with the idea that although the reader may disagree with the view chosen, he can at least follow the argument of this presentation without confusion. An attempt will therefore be made in Chapter I to analyze the current views of mind and of its functions, and later to locate the intelligence problem in relation to these views. II. Recognition of Types of Research. There was a time when what was known as psychological re¬ search was mainly speculation. One could sit down in seclusion, evolve theories, and record them as his contribution. The the¬ ories did not need to have much relation to evidence; and they were in fact not often anchored to anything in particular. They systematized themselves with reference to themselves, and re¬ mained essentially a closed circle. Then came the era of scien¬ tific experiment, and with it the demand that research cease to be speculative and become quantitative. It must observe, record, and systematize facts which had not up to that time been so handled by anyone else. It must make a genuine quantitative contribution to human knowledge. The demand for this quan¬ titative type of research did not carry with it an absolute ban upon philosophical theorizing ; but it did insist that theories must accord with facts, in so far as the pertinent facts were known; and that new quantitative researches should always be engaged in turning up additional facts, with which facts the theories must be kept in line. The real research lay in the development of the new facts. MODERN METHODS OF MENTAL MEASUREMENT 3 Such is now the prevailing view. But it may be pointed out that after such research has proceeded to a certain point, its own success develops the necessity for another type. To make this clear one has only to call attention to the fact that as experi¬ ment after experiment piles up endless facts in a given field cer¬ tain complications inevitably arise. This is particularly the case in the rather intangible field of the social sciences. The results of some experiments confirm each other in whole or in part; some are mutually contradictory ; while some are difficult to bring into any kind of relation with others. When the mass of the material on a given problem has grown to large proportions, and still the solution seems as far away as ever, it is time to take account of stock. It is time to attempt to find in the tangle a general trend which may point the way to a more profitable line of attack. That is, research is needed which is a search for organization within the products of other re¬ searches. This type of supplementary research requires that a rather exhaustive study of the field be made; that efforts of dif¬ ferent investigators be brought into relation to each other and to principles involved; that irrelevant details be excluded and relevant ones emphasized; and that the whole be brought to a focus. III. The Relation of Hypothesis to Research. The research for organization among the products of unrelated researches furnishes the basis upon which extensions may be at¬ tempted. Such a study of conditions makes it possible to for¬ mulate a guess as to certain other things which are probably true, but which have not yet been adequately proved. This guess, controlled by a consideration of the investigations which have preceded, is an hypothesis. Its significance is, or should be, de¬ termined by the significance of the previous work, and by the skill with which such work has been probed and interpreted. To continue quantitative work indefinitely without subjecting it occasionally to such clearing-house methods as result in a clari¬ fied and consistent hypothesis is, to say the least, wasteful. But 4 JAMES LEROY STOCKTON when the revised hypothesis has been arrived at, there then exists a logical demand for new quantitative work which shall put it to the severest test. IV. The Objectives of this Thesis as Guided by the Considerations Mentioned Above. A. To locate more definitely the problem of intelligence in re¬ lation to fundamental points of view in psychology. B. To use clearing-house methods of research upon the present situation with regard to intelligence in an attempt (a) to establish a definition of intelligence, (b) to discriminate types of intelligence, and (c) to discriminate a pivotal type. C. To further clarify the situation by relating existing quantita¬ tive studies to the types of intelligence. D. To develop an hypothesis concerning the fundamental na¬ ture of the pivotal type of intelligence; and to test this hypothesis by quantitative research. E. To apply the conclusions to a critical survey of modern methods of mental measurement. CHAPTER I Factors in a Psychological Setting for the Problem of Intelligence. I. Psychological views of the existence and function of sold , consciousness , mind, mental states. The 4 'mind and body” controversy has been a lengthy one, and it is not yet ended. Early psychology was philosophical, meta¬ physical. It was a speculative study of a consciousness called the soul, whose existence no one questioned. Along with this metaphysical psychology, there naturally appeared an empirical psychology, based upon attempts to describe psychic phenomena through the aid of introspection. Metaphysical and empirical psychology were supplements of each other in that empirical psychology was largely guided by metaphysical views; and meta¬ physical pschology, on its part, continually used empirical ma¬ terials. There arose a natural dualism, a contrast between soul (mind) and body (matter). Attempts to escape this dualism led, on the one hand, to the contention that matter was only an¬ other manifestation of spirit; or on the other hand to the con¬ tention that what was apparently spirit was only another mani¬ festation of matter. Thus there came about a division of psychological thinkers into spiritualistic monists, and material¬ istic monists. A hot-bed of discussion of these different points of view is found in the work of Huxley, Tyndall, Clifford, Romanes, etc. The main reason for the break between the old and new views lay in the growing scientific spirit, and in the conception of scientific law characteristic of that spirit. The belief that the world pro¬ cesses rest upon the law of cause and effect, coupled with the belief in the conservation of energy, made it seem impossible that any world of "mind” could "break in” upon a world of matter "locked up in mechanical causation”, and change the 6 JAMES LEROY STOCKTON cause and effect series. Such a breaking in would require the addition of some energy to that already existing in the world of matter, and so would controvert the law of conservation of energy. As philosophers the scientists might hold speculative views of such a possibility, but as scientists they could see no other answer to the dilemma than monism, either spiritualistic or materialistic. Moreover, with science avowedly dedicated to the study of facts which could be verified in the world of things, it is clear how the drift was toward materialistic monism and the elimination of the “soul” from scientific psychology. There continued, however, to be psychologists who were dual¬ ists, who discussed mind or consciousness, and who meant by it something the same as was meant by the metaphysical psycholo¬ gist’s concept of the soul. They continued at least to conceive of a world of mind and a world of, matter; and in spite of the scientific difficulties involved, they believed that the former did have something to do with certain changes which took place in the latter. They were forced to this view by their observation of the organism as an “adaptation system”. They saw this or¬ ganism changing its behavior with reference to its environment. That is, they saw that the mechanical systems of prearranged in¬ stinctive response did not always run to their apparently inevit¬ able conclusion. Behavior did vary to suit circumstances. Some of this variation, or adaptation, could be explained mechanically by the conflict of mechanical systems or otherwise; but some of it could not. The psychologist, judging certain other things by his experience with himself, believed that adaptation sometimes came about through an effective mental agent acting as a real power of choice between possible systems of action. Thus in his judgment the systems did not always run freely to their mechani¬ cal conclusions. He conceived of a mind or consciousness whose specific function was to interfere in those situations which de¬ mand behavior for which mechanical systems are inadequate. But it was necessary to put forth a theory as to how this re¬ lationship between the world of mind and the world of matter was possible. There could be but two theories. Either there was direct interaction between the two worlds, or there was par- MODERN METHODS OF MENTAL MEASUREMENT 7 allel action between them. Upon the theory of interaction the immaterial mental agent must leap the gap between it and the material world, and exert itself directly. This theory has not been very popular among the scientists, because it runs directly against the scientific difficulties already mentioned. Upon the theory of parallel action, however, the question was in a way pigeon-holed. It was admitted that the asserted gap between the material and the immaterial world does exist; that the human mind can not conceive of the immaterial as acting upon the material ; and that, therefore, the gap can not be con¬ ceived as bridged. But it was asserted that one could conceive of happenings in the immaterial world corresponding to, or parallel with, happenings in the material world; and that it was not at all necessary for the psychologist to explain how this was pos¬ sible. It was only necessary to postulate that when something happened in one world, it was paralleled by something in the other world. It was not necessary to conceive that one happened be¬ cause of the other. The claim was merely that when there was a happening in one world, there was a parallel happening in the other. But even this statement of the case needed to be, and was qualified. Not every happening in the material world as repre¬ sented by the nervous system, crowned by the brain, is accom¬ panied (paralleled) by consciousness — by a happening in the mind. The stimulation must reach a certain portion of the ner¬ vous system — the cortex of the brain, and there must be a cer¬ tain intensity of neural action in this cortex before the limen is passed and the mental life involved. But given this sufficient in¬ tensity of neural activity in the cortex, (in the material world), then the theory holds that there is parallel activity in the mind (the immaterial world). But what about the power of the mind to break in upon, and to modify, the happenings in the material world of neural activ¬ ity? What about the ability of the mind to execute its purposes? Parallelism is still a sufficient answer. One does not need to think of the change as caused by the mind. He only needs to think of the change as accompanying the given mental state. 8 JAMES LEROY STOCKTON The happenings in one world are conceived as so “set” or “tuned” with relation to the other world, that variation in one is accom¬ panied by variation in the other. It may even be that one is a mathematical function of the other; but even in that case the concept is one of mere concomitant, not causal, variation. If one uses the language of interaction, and speaks of the mind breaking in, it is only because such language is more direct and saves the circumlocution which would otherwise be necessary. In modern psychology, the so-called structuralists accept the parallelistic hypothesis, and so conceive the study of psychology in terms of the action of a nervous system paralleled under certain conditions by mind. They regard the organism as an adaptation system, and believe that mental changes accompany neural changes in the establishment of new adaptations for which the old mechanical systems are inadequate. They do not, however, make any attempt to tell how this occurs. They leave this ques¬ tion to philosophy, while they themselves study the nervous sys¬ tem in unexplained parallel relation to mind, and also try to ar¬ rive at the structure of mind through the aid of introspection checked up by the products of performance measured by labora¬ tory instruments of precision. This structural psychology was on its experimental side the child of the nineteenth century development of scientific physi¬ ology. But this trend toward scientific physiology and biology has also been responsible for the development of two other psy¬ chological points of view. The first of these is the functionalist view, and the second is the behaviorist view. Both regard the organism as an adaptation system ; both tend to speak in biological or neurological terms. Their work puts a strong emphasis upon the nervous system, upon stimulus, and response, neurons and neuron patterns made by prenatal bonds between neurons, or by new bonds resulting from experience. Over these neuron pat¬ terns plays the neural force in response to stimuli, and behavior is the result. The functionalist agrees with the structuralist in admitting the existence of mind, and in making free use of the terms mind, mental state, mental processes, etc. ; but his view is perhaps less MODERN METHODS OF MENTAL MEASUREMENT 9 dualistic and more materialistic in that he looks upon mind as “the functioning of the brain’5. There is for him a mental cor¬ relate of the physical brain process, but that correlate is the mere process by means of which the brain performs its function. This process, being something different from the brain itself, gives mind a place, and relates the functionalist to the structuralist. But instead of being especially interested in the structure of mind, the functionalist is especially interested in the achievements of mind. He is interested in development, in organic evolution, in how the process has come to be what it is, and in what is its teleological (purposive) significance. So the structuralist and the functionalist are not necessarily different persons. Structuralism and functionalism are different points of view, focused upon dif¬ ferent aspects of the total psychological field. They may belong at different times to the same person. The behaviorist frankly puts mind out of consideration. He says that no one has proved or can prove that there is or is not a mind. Moreover, he says that for the study of psychology it doesn’t make any difference. What is important in his opinion is behavior, and the possibility of the prediction of behavior, through the study of the nervous system, its original neuron patterns, and the formation of new patterns through experience. Hence he voluntarily relinquishes the study of mind in favor of the study of behavior explained by a nervous system operating by mechanical, biological law. Behavior counts; it is tangible. It can be objectively measured, is entirely free from metaphysical speculation, and is therefore the real subject matter for science. There is no doubt that there is a place for this view of the behaviorist. There are certain psychological problems which can be attacked only on the basis of objective data, and this fact gives the behaviorist his field. But again it would seem that it is a part, only, of the total field, cut off by the limitations of a cer¬ tain view which may be taken by any psychologist at any time. To regard it is an exclusive and all-embracing view, and so to give up the conception of mind as a directive agent, would seem to make the organism a mere automaton at the mercy of external influences. Certain psychologists are not willing to do this. 10 JAMES LEROY STOCKTON They feel that the automaton theory is outworn, and that man, at least to a certain extent, can exercise a power of initiative and thus influence his destiny through purposeful choice between re¬ sponses. They feel that the prediction of behavior must be very incomplete without a study of this mind which has the power to vary behavior through deliberate choice. Thus they feel that to make psychology purely a study of organic behavior without raising the question of a directing mind is almost or quite to make it a study of biology or neurology. It is to them, in a sense, psychology with the psychology left out. Thus it is clear that if one is to talk about intelligence as a psychological phenomenon, he must choose a definite point of view, especially with regard to the mooted mind or conscious¬ ness. This point of view, it goes without saying, need not be exclusively structural, functional, or behavioristic. The view here taken will agree with the tendency of modern psychologists of all schools to drop the use of the word conscious¬ ness in favor of the word mind, or of the expression mental state, since consciousness sometimes carries with it a connotation more philosophical than scientific. There will, however, be dis¬ agreement with some psychologists in that ( i ) it will be assumed that mind does exist coextensive with a certain intensity of neural activity in the cortex, and (2) in that the parallelistic hypothesis will be accepted, but for convenience the language of interaction will be used. The specific function of mind will therefore be conceived as that of breaking in upon the mechanical causation of mechanical systems of response, thus making itself felt in changed behavior. II. The modern theory of a unitary mind. The assumption that mind exists, and at times exercises a di¬ rective power over behavior, has been accepted. Another step may be taken through the medium of a discussion of mental “faculties”. The older metaphysical psychology, in its attempt to analyze the soul, naturally discriminated such faculties (func¬ tions) as sensation, perception, memory, imagination, etc. Even the most modern parallelistic hypothesis must be carefully safe- MODERN METHODS OF MENTAL MEASUREMENT ii guarded or it falls into the same trap. The very attempt to dif¬ ferentiate between brain and mind is conducive to the difficulty. One thinks of neural activity in the cortex, and of a gradually increasing intensity in this activity. Perhaps it is a neural activ¬ ity stimulated by light. When the intensity passes a certain limit the brain activity is paralleled by the simplest possible mental activity. This simplest possible mental state is given the name sensation. It becomes immediately natural to say that the mind has a faculty of registering sensations, and to discuss sensation as a mental faculty. As more and more stimuli bent upon the end organs, raise the intensity of neural activity in the brain, and are paralleled by more and more sensations, immediate sensations merge with the associated past sensations into percepts. This gives the mind a faculty of perception. Then the power to bring back to mind the image of the thing itself is focused upon. Recognized images are responsible for a faculty of memory ; vivified and reconstruct¬ ed images, for a faculty of imagination ; images used as symbols of meaning, for a faculty of ideation; and the relating of these images, for a faculty of thinking. The difficulty with this scheme does not lie so much in the con¬ ception of the “faculties” as it does in the emphasis upon the in¬ dependence of the faculties in action, and the correlated emphasis upon their ability to take training. The view was naturally evolved that through the training of any particular faculty a particular kind of power could be stored up and remain ready to be drawn upon for future use. Specific memory power, specific thinking power, etc., could thus be put in “cold storage” as it were, for a season when they might be needed. Modern psychology, however, for sufficient reasons which do not need to be detailed here, has largely discarded the faculty idea, together with much of its attendant storage or “reservoir” theory. Some of the faculty names are preserved, because they express something which only the names can compass ; but, never¬ theless, mind, to the modern psychologist, is not cut up into sep¬ arate parts, and does not act in separate parts. Mind acts as a whole, as a unit. When there is mental activity, it is activity of 12 JAMES LEROY STOCKTON the whole mind — of a unitary mind. But this unitary mind can be focused in various directions. That is, one may speak of memory as a typical process of psychical activity. Mind as a whole, acts in this form. Recall is the main consideration, and is in the foreground ; but all of the rest of the mind is in the back¬ ground contributing its part. An analogy may be found in the one-celled organism, the amoeba, which can wrap a fold of its body about a minute particle of food, use the enclosing sack as a stomach, and digest the food. The focus is toward the sac; the form of activity is digestion ; but all the amoeba body behind the sac is contributing its share to the process. The digestive func¬ tion is a function ; but not a function separate and independent in action. To carry the illustration a little further, the amoeba can also, in its attempts at locomotion, put forth a “foot” in any direction. Thus the body is focused anew in a new form of activ¬ ity; but the foot is not separate and independent. It is, as it were, only a sign of the complete and unified action of the whole. It is only in some such sense that terms such as sensation, memory, imagination, etc., are used in modern psychology. When neural activity of sufficient intensity occurs in the brain it is accompanied by sensation in the mind. But it is to be par¬ ticularly remembered that this means just what it says. The sensation is in the mind so definitely as to be really but a name for a focus of the total mind. It is a sign of the complete and unified activity of this focused total mind. It is in such a sense, only, that use is made in this thesis of the term mental function, or of the specific names of specific functions. CHAPTER II Current Views of Adaptation and Mind in Relation to Intelligence. I. The confusion which these terms present. Psychologists are agreed upon regarding the organism as an adaptation system. There is a difference of opinion about the role played by mind ; but the assumption is here made that mind exists, and that it is, at times, a directive agent in adaptation. What about the relation of the terms adaptation and mind to the term intelligence? Current usage is very loose, and the result is confusion which can be cleared up only by first finding some com¬ mon ground upon which all views meet, and then analyzing the difficulties beyond that point. The common ground is found in the fact that all usage agrees in placing the problems of intelli¬ gence within the problem of adaptation. Further analysis, however, shows that there are writers who are willing to call all adaptation intelligent. They think of in¬ telligence as belonging to the organic as opposed to the inorganic:; and they think of the organic as able to adapt itself to environ¬ ment, while the inorganic can not. Possibly some who passively accept this point of view have not even stopped to consider that the organic includes vegetable as well as animal organisms, and that vegetable organisms do make adaptations to environment. If this were called to their attention they would probably readily agree that in saying that the organic has intelligence, and the inorganic has not, they had meant to contrast only animal organ¬ isms with the inorganic. There is a class of persons, however, who intentionally include both animal and vegetable organisms when they contrast the or¬ ganic and the inorganic, and who are willing to call both animal and vegetable organisms intelligent, because of the power of adaptation which they possess. That is, some persons do inten- 14 JAMES LEROY STOCKTON tionally claim that ability to make adaptations is identical with intelligence. The source of the confusion lies in the failure to realize that adaptation is such a broad term that it must be split up into a number of different types of adaptation. Unless these types are discriminated in thought and terminology, those who discuss the subject are not speaking the same language because they are not giving the same connotation to the terms which they use. Hence the discrimination of adaptation types is the next problem. II. Types of adaptation in relation to mind and intelligence. A. ADAPTATION IN THE INORGANIC WORLD. There is a use of the word which permits it to apply to the in¬ organic. Cliffs and other earth contours “are adapted to environ¬ ment' ’ when they yield to weathering by wind and water. Iron rails are adapted to environment when they expand or contract because of change of temperature. But these bodies are adapted to the environment ; they do not adapt themselves. They remain passive, and are mechanically adjusted through the play of ex¬ ternal agencies. Given approximately the same conditions, the variations which occur tend to be predetermined, and are there¬ fore highly predictable. The body exhibits no spontaneity. There is no active, inner, selective factor which interferes to make the prediction of variation uncertain. Now the idea of intelligence, no matter how else limited, has never failed to carry with it the assumption that, to some degree at least, the possessor is able to exercise a relatively non-predic- table selective inner influence upon its own destiny. Hence there is no current reputable usage of the term intelligence which will permit its application to the inorganic. This is so self-evident that it would be a waste of words to say it, if it were not for the slip which sometimes identifies intelligence with adaptation. The inorganic does, in a sense, have adaptation. It does not have intelligence. Hence intelligence cannot be used as synonymous with adaptation without opening the door to confusion. Accord¬ ingly, in organizing the uses of the term adaptation, this thesis MODERN METHODS OF MENTAL MEASUREMENT 15 will distinguish between inorganic and organic adaptation, and will deny intelligence to the inorganic. B. ADAPTATION IN THE ORGANIC WORLD. i. Primary mechanical types. a. Tropic adaptation. — There is a difference of opinion as to where to draw the line between tropism and real reflex or instinc¬ tive acts. The view here taken will be that which limits tropism to those organisms which lack a differentiated nervous system.* Such primitive organisms possess a generally diffused sensitive¬ ness of the total protoplasmic mass. This sensitiveness promotes simple adaptation, but these adaptations have much of the same invariable (and therefore predictable) character as do the adap¬ tations in the organic world. Water, light, and heat have been spoken of as having certain mechanical effects upon inorganic substances. They have also a total mechanical effect upon or¬ ganic tissue, and through this effect may promote adapta¬ tions. But again, the body (even though it be organic) is adapted to the environment, it does not adapt itself. Again there is no active, inner, selective factor, no initiative, which in¬ terferes to make the prediction of variation uncertain. Hence in one sense there is no variation at all, and certainly no intelligence. b. Reflex and instinctive adaptation. — In inorganic adaptations and in tropism there is assumed to be no intelligence, since it is conceived that in them the adjustments lack spontaneity, and are practically predictable. The body is at the mercy of its own ma¬ terial composition as acted upon by external agencies. But with instinctive adaptation it is different. Instinct utilizes a dif¬ ferentiated nervous system and succeeds in being less rigid, less predictable, and more selective, though the selection occurs in a mechanical manner. Herrick says that theoretically the simplest organized nervous response is the reflex which depends upon merely the simplest re- * Whether or not this includes plant life is a somewhat mooted question ; but the essential facts of the present discussion will not be unfavorably af¬ fected if this question is dropped, and the matter discussed wholly from the point of view of the animal organism. i6 JAMES LEROY STOCKTON ceptor and effector organs, and one motor and one sensory neuron. He says further than some writers have been willing to classify such reflexes with the tropisms; but that others con¬ ceive the pure reflex as more theoretical than actual, and tend to move immediately from unorganized tropism to the instinctive response regarded as a group of reflexes. The latter view will here be taken. From one point of view the organized nervous response known as instinct, is entirely mechanical, prearranged. It is regarded as a selective or choosing agency, yet as selecting those stimuli, only, to which it is tuned to respond mechanically, and as always responding in the same way to the same stimuli. It is thought of as rejecting or ignoring the different; but when a stimulus comes which is similar to that to which it was meant to respond, and to which it has always responded, it is conceived as responding again in the same way. This view is only relatively true. The organism which responds instinctively through the aid of a nervous system is not so rigid and invariable in its adap¬ tation to environment as are inorganic bodies, or even those crea¬ tures that depend upon tropisms. The nervous mechanism per¬ mits a certain limited initiative or self-adjustment in adaptation, although one must hasten to say that self-adjustment is not here used in the sense of purposive or intentional adjustment. There is merely a mechanical selection, based upon limited possibilities residing in an originally organized mechanism. Birds of the same species build similar nests ; but no two of them build nests exactly alike in all particulars. No one conceives that the bird in¬ tentionally selects the changes. The power of selection lies in the elasticity of the mechanism, and this elasticity is limited. Yet to this limited degree the creature of instinct does influence its destiny through the exercise of an active, inner, selective factor; and to this degree its variation is non-predictable. The organ¬ ism in a measure adapts itself, and is not adapted to its environ¬ ment. This has led many to wish to use the word intelligence to apply to these mechanical variations in instinctive behavior. There is a limited sense in which the word might be so used. A problem has really been solved through focus upon a situation, MODERN METHODS OF MENTAL MEASUREMENT 1 7 plus action which is based upon selected (chosen) similarities. But the control in the whole process is mechanical and not in¬ tentional; and if the term intelligence is applied, it needs to be qualified by emphasis upon the mechanical control. This type of mechanically controlled intelligence, this plasticity in original in¬ stinctive response, is unlearned, and in that sense non-productive. Only original neural patterns are called upon ; but there is a limited mechanically controlled choice between persistent originally ar¬ ranged systems woven between the neurons which are the units of the nervous system. c. Modified instinctive adaptation. — But original instinctive response does, at times, through the mere conflict of the original mechanical systems, cease to be the only resource of an organ¬ ism. As an illustration it may be noted that an organism may have an original system of response which makes it tend to avoid pain through withdrawing movements. It may have another original system which leads to approaching movements in the presence of a bright object, e.g., a hot stove. The mere mechani¬ cal conflict of these two systems may lead to the suppression of one of them and to the supremacy of the other. The characteristics of this type of adaptation are very similar to those of original instinctive adaptation. The choice is on the basis of similarities; and a problem is solved, although there is no formation of new neuron patterns. The variation is also less predictable than in tropisms or in inorganic adaptation. The or¬ ganism is not merely adapted to environment. To a degree it has initiative and it adapts itself. There is an inner, active, selective agency at work, but the control exercised by this agency upon the destiny of the creature is mechanical and not intentional. If there is intelligence, it is still mechanically controlled intelligence. Learning may be said to have taken place, because the variation, unlike that in original instinctive response, is not merely a me¬ chanical choice between persistent possibilities, but is the result of a permanent suppression of one original tendency in favor of another original tendency. Thus the act is productive mechani¬ cally controlled intelligence. d. Associative adaptation. — In the types of adaptation thus far i8 JAMES LEROY STOCKTON noted, no new neuron systems are formed. There is often, how¬ ever, an excess neural discharge. This comes especially in times of emotional excitement. Many random movements are then made as the excess discharge forces itself through new channels. If discharge through a new channel brings satisfaction, the new movement is associated with it, and this movement comes more certainly the next time. Thus gradually new neuron patterns are formed and behavior is varied ; problems are solved ; learning takes place. This learning utilizes the neural-switchboard, and shoots upward to a sensory-motor level above the level of the mere reflex arc; but it does not go high enough to get into the level of intentional control. It is at first a chance choice due to mechanical spontaneity, and it is continued as a mere mechanical association with a sense of well-being. Even rote learning of a song or other school exercise may occur in the way just described; and many common manners and customs also have the same origin. The problem is not inten¬ tionally or logically attacked ; but repetition, plus a favorable af¬ fection, blocks out the new pathways, and establishes the new neuron bonds or patterns. It is only trial and error learning, or incidental learning. Yet the creature is not merely adapted to its environment. It adapts itself, although in a mechanical manner. Therefore the word intelligence is applicable if the act is realized to be an example of mechanically controlled intelli¬ gence. Mind, if present at all, is still not a directive agent. In popular terms, a mechanical habit has been mechanically formed. This type of adaptation is the least predictable type thus for discussed. 2. Purposive Type. a. Intentional adaptation. — There have been discussed two types of unintelligent adaptation: (a) the inorganic adaptation; and (b) tropism. There have also been discussed three types of limited-intelligent adaptation: (a) original instinctive adapta¬ tion; (b) modified instinctive adaptation; and (c) associative adaptation. But there comes a time in the life of an organism when none of these types of adaptation can meet the new situation MODERN METHODS OF MENTAL MEASUREMENT 19 which is presented. When such a time appears, the organism suffers, or even perishes, unless it is an organism possessing a mind which can break in to solve its problem by influencing the nervous currents to the formation of new neuron patterns neces¬ sary to a new adjustment intentionally chosen out of the possibili¬ ties which the situation presents. The theory involved in the interference of mind in the forma¬ tion of new systems of response has already been briefly out¬ lined. It is that there must be involved a certain grade of refine¬ ment of the nervous structure found only in the cortex, and a certain intensity of the neural activity in the cortex, before the limen is passed and the mental life is able to function. That is to say, that mind is coextensive with (1) a certain intensity of neural activity, and (2) in certain structures. One of these con¬ ditions alone is not enough. Mere intensity in the lower struc¬ tures, or mere activity in the cortex, must give place to a certain intensity in the cortex before the limen is passed. (But it is conceivable that cortical activity which is not intense enough to pass the limen may have an indirect mechanical influence upon mind, through its influence upon the cortex. ) Below the limen, therefore, is mechanically controlled adap¬ tation. The function of this intentional activity of mind is to meet those emergencies in which the mechanical systems break down. Asuming that mind is able to do this, a certain analysis may be made of the method. This analysis cannot fail to be rather rigid and dogmatic, but it is not intended to be inflexible. All discussion of types must attempt to make the type specific as if it stood out sharply by itself, even though in reality it grades imperceptibly into adjacent types. Purposive adaptation does not always appear unadulterated ; but, theoretically, in its pure form, it presents the following named elements, each one of which is to be understood as intentionally carried out: 1. Focus upon possibilities; in other words, concentration, or attention. 2. Pause; the mechanical currents must be temporarily in¬ hibited. 20 . JAMES LEROY STOCKTON 3. Selective activity; significant elements in present and past situations must be abstracted and held by themselves. 4. Relating of the selected elements.* 5. Action upon the relationships discovered. When the literature is examined in the next section it will be found that the modern tendencv is to reserve the term intelli- •/ gnce for this type of adjustment, or adaptation, which solves prob¬ lems by the steps just enumerated. However, if one has de¬ cided to use the expression ‘'mechanically controlled intelligence” for unintentional adjustments, he can use a qualifying term for these directed adaptations, and call them “intentionally controlled intelligence.” They may also be called productive intention¬ ally controlled intelligence, since they really produce new connec¬ tions, and new behavior. This same type of adaptation has other names such as inten¬ tional learning and thinking. It represents the height of power of the active, inner, selective factor which produces non-predic- table variation. It is the means by which the organism escapes being merely adapted to its environment, and succeeds in adapt¬ ing itself to the environment, or in adapting the environment to itself. It is the open door to controlled progress. Throughout this thesis therefore there will be made an at¬ tempt to separate the various aspects of mechanically controlled adaptation from intentionally controlled adaptation. The follow¬ ing list of terms wll help to insure this separation : Inorganic adaptation (unintelligent). Organic tropic adaptation (unintelligent). Non-productive mechanically controlled intelligence. a. Original instinctive adaptation. Productive mechanically controlled intelligence. a. Modified instinctive adaptation. b. Associative adaptation. Productive intentionally controlled intelligence. *What kinds of relationships is the mind able to conceive? Cause and effect, time, space, genus-species, part-whole, likeness and difference ; how many are there to be found? Can all be reduced to one; viz., similarity? Time relationships are gathered because they are similar; so with place relationships, etc. Then ability to relate becomes just that ability which is able to recognize in present experience an element similar to one belonging to a past experience. MODERN METHODS OF MENTAL MEASUREMENT 21 3. Secondary mechanical type. a. Reproductive (habitual) adaptation. — It is well known that an act which once required the immediate, purposive supervision of mind, may, through repetition and other circumstances, fall back to be performed by new-formed mechanical-neural systems. Mind is thus released for new ventures in new fields. The act that is thus relegated to mechanical systems is no longer an in¬ telligent act in the sense of intentionally controlled intelligence. It is intentionally controlled intelligence only in so far as it has not been so relegated. The process of relegation consists in a gradual fading away, out of the focus of mind into the fringe. The act thus becomes more and more predictable, and finally drops entirely below the limen into the mechanical, the unintel¬ ligent, or the mechanical-intelligent, if one wishes to use this term. It becomes habit, and, for the purposes of this discus¬ sion, belongs with the mechanical adaptations. In this connec¬ tion it can, through mechanical conflict with other mechanical systems, bring about mechanical learning, just as in the already discussed conflict of two original mechanical systems. But this act which was once intentionally controlled, and has now become mechanical, has not at all the same significance as the original mechanical. It stands not only for mechanism, but it stands also as evidence of a former exercise of intentionally con¬ trolled intelligence. It can be brought back into the intentional ; and it could not have been performed at all without the original exercise of the intentional. It is, therefore, secondary evidence of intentionally controlled intelligence, since in all probability, the formerly exercised power still persists in the organism. And this secondary evidence often has an importance nearly or quite equal to the primary evidence afforded by a new adaptation itself. This secondary evidence of intentionally controlled intelli¬ gence, this giving back of something learned at a previous time, may be called pedagogical intelligence, or reproductive intelli¬ gence. It is the diary of the intentionally controlled intelligence. 22 JAMES LEROY STOCKTON III. The definition of intelligence. It has been customary among students of intelligence to say that it is not known what intelligence is. The view taken here is that what has been meant is that types of intelligence have not been discriminated, or that the fundamental nature of intelligence has not been known ; but that it has been known what intelligence is, and that the preceding discussion has shown what it is. To accomplish this end did not require experimentation, but only an examination of the usage of the word. For any term has content only through usage, and that usage may give it any content what¬ ever. It has been shown that the usage of the word intelligence has been rather definite, except that types of intelligence have been allowed to overlap. It follows that the definition of intelligence should be broad enough to include all types admitted by usage, and that supplementary definitions of the individual types should be given. The broad and all-inclusive definition may be worded as follows: An organism is intelligent when it possesses the ability TO INFLUENCE ITS DESTINY THROUGH THE UTILIZATION OF AN INNER, ACTIVE, NON-PREDICTABLE, SELECTIVE FACTOR WHICH CHOOSES ON THE BASIS OF SIMILARITY. This definition, since it includes mechanical choice, does allow intelligence to practically all animal organisms; and that is just what some writers of importance wish to do. If, however, one wishes to distinguish intentionally controlled intelligence as a pivotal type (and this is the only type which many writers rec¬ ognize) he must make a more qualified definition as follows: An organism has intentionally controlled intelli¬ gence WHEN IT POSSESSES THE ABILITY TO INFLUENCE ITS DES¬ TINY THROUGH THE INTENTIONAL UTILIZATION OF AN INNER, ACTIVE, NON-PREDICTABLE, SELECTIVE FACTOR TO EFFECT A SPE¬ CIFIC PURPOSE THROUGH INTENTIONAL CHOICE BASED UPON SIMI¬ LARITIES. IV. Summary of Chapter II. I. It is agreed that the problem of intelligence is within the problem of adaptation. MODERN METHODS OF MENTAL MEASUREMENT 23 2. But adaptation is in no sense intelligent until a body utilizes an inner, active, non-predictable, selective factor to influence its destiny. Hence inorganic adaptations, and even organic tro- pisms, are not intelligent. 3. Organized response may be mechanically controlled as in (a) original instinctive adaptation; (b) modified instinctive adaptation; (c) associative adaptation. If these are regarded as intelligent at all, it can only be in a limited sense, and they should be known as mechanically controlled intelligence. 4. Organized response may be intentionally controlled. This is the type of adaptation generally recognized as intelligent. It is intentionally controlled intelligence in contrast to the mechani¬ cal control. Its variation is relatively non-predictable. 5. Intentionally controlled intelligence may lapse into mechan¬ ism, and become a secondary mechanical type, valuable as the diary of the intentionally controlled intelligence. 6. Intelligence may, therefore, be defined as in Section III of this chapter. CHAPTER III Types of Studies in the Quantitative Determination of Intelligence. The lack of discrimination between the types of adaptation discussed in the last chapter, has naturally encouraged looseness in discrimination between types of experimental studies of intelli¬ gence. There is also an added difficulty arising from the ten¬ dency to claim that one has measured intelligence when, in reality, he has not done so at all, but has only measured some trait cor¬ related with intelligence. These points will be covered very brief¬ ly in the present chapter, the latter being taken up first. I. Measures , not of intelligence , but of factors found to be correlated with intelligence . A. CORRELATION OF PHYSICAL TRAITS WITH INTELLIGENCE. If it is found that intelligence usually goes with a head of a certain width or length, then the measuring of the heads of a group of people may give an insight into the probable amount of intelligence in the group. But, in spite of this, it cannot then be truthfully said that the intelligence has been measured. The presence of intelligence has only been inferred as a result of the head measurements. In one sense the result is the same no matter how it is stated; but, if, in such a case, intelligence is really thought of as measured, false ideas as to the true nature of in¬ telligence are fostered. Good examples of the measurement of physical traits correlated with intelligence are found in the early part of the first volume of Whipple’s “Manual of Mental and Physical Tests”. First are certain anthropometric measures, such as have often been used in the identification of criminals, and in the relation of growth to disease, etc. Definite degrees of these traits have also been found MODERN METHODS OF MENTAL MEASUREMENT 25 usually to be associated with intelligence, and the presence of the given degree of the trait therefore leads to the inference of the presence of intelligence. Examples of such measurements are those of height (standing and sitting), weight, diameter of skull, girth of skull, etc. In like manner are utilized measures of vital capacity, strength of grip, physical fatigue, quickness of move¬ ment, accuracy of movement, and involuntary movement. The same thing also applies to measures of sensory defect due to physical conditions. Deafness, long- and short-sightedness, color¬ blindness, control of eye muscles, and such may be cited as ex¬ amples. Any one of these traits may be found in varying degrees of correlation with intelligence or lack of intelligence. To meas¬ ure the trait may lead to results which justify the assumption that intelligence will be found along with it ; but it does not determine the degree of the intelligence either for the group or for the indi¬ vidual. B. CORRELATION OF MENTAL TRAITS WITH INTELLIGENCE. Studies which merely show that amount of perception, memory, etc., is correlated with intelligence, are not measures of intelli¬ gence itself. Again it will prevent confusion concerning the true nature of intelligence if such studies can be set off by themselves as the studies of physical traits have been. It is common to think of a person of good perceptive power, good memory power, etc., as an intelligent person. But it has been repeatedly proved that even the feebleminded may possess these powers. The difficulty lies in the identification of (1) the admitted possession of the trait, with (2) the ability to manipu¬ late the trait in the service of non-predictable variation. Per¬ cepts and memories are bundles of relationships. A person is not born with them. Hence their building up may be called varia¬ tion; but, in the main it is a predictable variation. There is a natural course of events on the basis of which one could, if he knew all the circumstances, predict the formation of percepts, memories, etc., just as he could under similar circumstance pre¬ dict the crystallization of steel under shock. This predictable variation, the main objective of the extreme “Behaviorist”, is not 26 JAMES LEROY STOCKTON intelligence. Intelligence is not present until mental elements (functions) are, either mechanically or intentionally, brought into relationships which result in non-predictable variation. The real measure of intelligence measures spontaneity or initiative. It is true that in the formation of percepts, etc., there may have been present in a particular case some of this initiative (mechanical or intentional) ; but much of the process is likely to have been of the predictable kind ; and one does not with certainty get at the spontaneity, therefore, through the measure of the function. The functions are prerequisite to intelligence, since the initiative can not come if the functions are lacking. But the functions may by measurement be found in varying amounts, and yet intelligence, non-predictable variation, be lacking, or at least unproved because it is obscured by the excess of predictable variation with which it is associated. If one wishes a reliable measure of intelligence he tests not the amount of the function, but the amount of initiative which the creature can produce through the discovery and utiliza¬ tion of relationships between the functions. Examples of quantitative measures of sensation are the com¬ mon tests of visual acuity (Whipple, Test 14), and auditory acuity (Whipple, Test 18), etc.; of perception, are the common tachistoscopic tests of range of visual attention (Whipple, Test 24), and visual apprehension (Whipple, Test 25), etc.; of rote memory, (Whipple, Test 38), etc. One may find these and other mental abilities correlated with intelligence ; but the meas¬ urement of them is not a measurement of intelligence itself. II. Real measures of intelligence. A. MEASURES OF MECHANICALLY CONTROLLED INTELLIGENCE. i. Original types (unlearned). Here belong all those studies of endowment which aim to achieve a knowledge of the amount of a creature’s orginal and unlearned ability to solve problems, e.g., non-predictable varia¬ tions in the nest building of birds, in the migration of species, in the food habits of wild mice, etc. The variations here studied, however, are those which come within an original range of native MODERN METHODS OF MENTAL MEASUREMENT 27 ability, and not those which supplant or augment original abili¬ ties. They are discussed in the former chapter under the head of original instinctive adaptation. 2. Learned types. These are the ones previously discussed as modified instinctive adaptations and associative adaptations. They represent real non-predictable variation, but it is still of the mechanically con¬ trolled type. The field has been much exploited, and illustra¬ tions are numerous and well-known. Typical ones are the ani¬ mal intelligence experiments of Lloyd Morgan, Thorndike, Yerkes, and Watson. All experiments in unintentional, associa¬ tive, learning, or incidental learning in either human beings or animals belong here. It may be said in passing that if the distinction between me¬ chanically controlled intelligence and intentionally controlled in¬ telligence were kept well in mind, much light would be thrown upon the dispute as to whether or not animals are intelligent. Animals do solve problems, but the consensus of opinion is that they solve them either through the small latitude of non-predict- able variation allowed by instinct, or they solve them through conflict of instincts or through association. They do not solve them through working out of a deliberately chosen purpose based upon relationships intentionally sought between mental elements. From this point of view, animals have mechanically controlled intelligence, but not intentionally controlled intelligence. B. MEASURES OF INTENTIONALLY CONTROLLED INTELLIGENCE. Illustrations of intentionally controlled intelligence must be those featuring immediate and intentional problem solving. There can be included no primarily mechanical associative or instinctive processes. A new situation presents itself and is pur- posively attacked and solved through the discovery of new rela¬ tionships. Cats get out of cages through mechanically controlled intelligence. A normal human being in the same situation uses intentionally controlled intelligence, and attempts purposively to 28 JAMES LEROY STOCKTON apply past experience to the present situation, find the similari¬ ties between the past and present, and so find the way out. Some of the best developed modern single measure of inten¬ tionally controlled intelligence are certain tests of intentional sensory discrimination, certain picture-completion and other per¬ formance tests, the synonym-antonym test, the analogies, etc. As has already been said, this type of intentionally controlled adapta¬ tion is the only type that many writers are now willing to call intelligence; but it can do no harm to call mechanical phases of adaptation mechanically controlled intelligence, if mechanically controlled intelligence is definitely discriminated as a type. C. MEASURES OF REPRODUCTIVE INTELLIGENCE. The human mind is so constituted that after it has solved a problem once or several times, the solution becomes mechanical. At first there is required active attention and intention; later attention becomes what has been called secondary passive, inten¬ tion drops out, and the act performs itself. It becomes repro¬ ductive intelligence because it reproduces mechanically the acts of the intentionally controlled intelligence. Many persons have not been willing to call pedagogical tests intelligence tests. It is true that a test in geography or history may require merely the mechanical reproduction of something previously learned; but the person may, and probably did originally, pick up much of the knowledge intentionally. And psychologists are more and more coming to believe that measures which determine how much a person has intentionally achieved through a term of years are often more significant than those measures which only find out his present achievement through a period of an hour more or less. So psychologists are not nearly so much afraid as they used to be of the pedagogical measurement regarded as an intelli¬ gence measurement. There is, however, a fundamental diffi¬ culty in the fact that one seldom is able to tell exactly how much of the reproduced material was originally acquired mechanically, and how much was acquired intentionally. Hence one cannot tell how much credit to assign to mechanically controlled intelli- MODERN METHODS OF MENTAL MEASUREMENT 29 gence, and how much to assign to intentionally controlled intelli¬ gence. Illustrations of pedagogical (reproductive intelligence) meas¬ ures are those of arithmetical fundamentals such as the Courtis, series A and B ; arithmetical reasoning, such as the Stone Reason¬ ing Test; reading scales, such as the Kansas standardized read¬ ing tests; handwriting scales, such as the Thorndike scale and the Ayres scale; and the composition scales, such as the Hillegas scale, the Harvard-Newton scale, and the Willing scale. In fact one now finds such scales for practically every subject of instruction. CHAPTER IV The Fundamental Nature of Intentional Adaptation. I. The “ common factor ’ in intelligence. Certain types of adaptation have been discriminated in previous chapters. Evolutionary tendencies in modern thought would naturally lead one to suspect a development from one type to another, but it is not the intention to pursue that idea at this time. It is now necessary, however, to call attention to the fact that the discriminations heretofore made between the non-intelli- gent, the mechanical-intelligent, and the intentional ( purposive )- intelligent, are all based upon the conception of a “common factor” in intelligence. That common factor has several names such as seeing relations, thinking, judging, profiting by exper¬ ience, etc. ; and its exercise results in initiative, spontaneity, or non-predictable variation. Binet’s own statement of this common factor is very significant, although he does not use it to make the distinctions herein urged. He says :* “It seems to us that in intelligence there is a fundamental faculty, the alteration or the lack of which is of the utmost importance for practical life. This faculty is judgment, otherwise called good sense, practical sense, initiative, the faculty of adapting one’s self to circum¬ stances. To judge well, to comprehend well, to reason well, these are the essential activities of intelligence. A person may be a moron or an imbecile if he is lacking in judgment; but with good judgment he can never be either.” Hence it is here con¬ ceived that where the capacity for judgment and non-predictable variation is lacking, intelligence is lacking. It has also been shown that above the unintelligent, there is a level of mechani¬ cally controlled intelligence (original and acquired), marked by mechanical judgment; and above that, a level of intentionally * The Development of Intelligence in Children, Vineland Laboratory, 1916; p. 42. MODERN METHODS OF MENTAL MEASUREMENT 3i controlled intelligence, marked by purposive judgment. It may be pointed out that the discrimination between the mechanical- intelligence and the purposive-intelligence is a discrimination based not upon quantity of the common factor, but upon quality of that factor. Judgment, initiative, spontaneity, of a mechani¬ cal quality marks mechanically controlled initiative. Judgment, initiative, spontaneity of a purposive quality marks intentionally controlled intelligence. The remainder of the thesis will be oc¬ cupied with attempts to determine the fundamental nature of the intentional or purposive type of intelligence, together with a consideration of the implications arising from the conclusions reached. There are, of course, all degrees of gradation between a com¬ pletely mechanical adaptation, and one which is completely in¬ tentional. It is even true that very many adaptations which on the surface are intentional, are at bottom a mixture of both types. But since the crucial importance of the intentional type as the key to directed human progress is acknowledged, and since it does, at times at least, occur approximately according to the rather schematic plan already outlined, it can do no harm to con¬ tinue the discussion from that standpoint. In the type of adaptation under consideration, mind is con¬ ceived to be an active factor. Through it a positive purpose of an individual is carried to its conclusion. It is a method of active solution of problems, through focus upon the possibilities of the situation, pause, selection of significant elements, and the recognition of relationships between the selected elements. But what are the elements between which relationships are found? They may be perceived material things, images of things, or symbols of things. With relation to any pair of such elements, thinking is possible. Each one of the pair is, as it were, held out by itself, and compared with the other. Then de¬ cision is made as to whether or not they belong together. But it is at first easier to do this when the objects can be obtained and handled (perceived) than it is to deal with images of the objects. And it is easier to deal with the images than it is to deal with symbols of the images or of the things themselves. Long before 32 JAMES LEROY STOCKTON there was any organized science of psychology the intuitive psy¬ chology of the people made its own statement of this fact by saying that it is easier to solve a problem in the concrete than in the abstract. It is the idea involved in this natural and funda¬ mental usage which is to be here appealed to in attempting to solve the fundamental nature of intentionally controlled intelli¬ gence, just as usage was appealed to in former chapters to estab¬ lish the definition of intelligence. The relationship under consideration is apparent even in dif¬ ferent degrees of development of the human race. The savage does not deal with abstractions so easily as with the concrete things that come to his hands. The average intelligent member of modern civilization who easily solves ordinary problems in arithmetic, finds himself baffled in the presence of the same prob¬ lems put into generalized terms. Inevitably when thinking of these things one leans toward a genetic theory of development even within intentionally controlled intelligence itself. For al¬ though the mind acts as a unit in intentional control, it is never¬ theless easy to believe that early in the evolution of this power, although all possibilities of mental action were potentially pres¬ ent, the unit-activity (function) of perception was predominant in problem solving. On this theory, progress has consisted in the gradual supplementing of the perceptual activity by other unit-activities involving images and symbols. Moreover, it seems probable that this same progression rough¬ ly characterizes the life of the individual. It is probable that in his acts of intentionally controlled intelligence he deals easiest and oftenest with things, then with images of things, then with sym¬ bols. Upon this theory, feeblemindedness, which is now every¬ where recognized as retardation in mental development, is a re¬ tardation in passing from the preponderance of one of these forms of activity to another. Thus the common factor, judg¬ ment, again asserts its power by determining levels even within intentionally controlled intelligence itself ; and the person of low purposive intelligence is seen to be the one arrested primarily upon the level of concrete relationships, which his more fortunate mates pass on to the more ready manipulation of the image and MODERN METHODS OF MENTAL MEASUREMENT 33 the symbol. But again it is quality, or type, of judgment, and not quantity, which determines the levels; although one is, of course, immediately interested in the quantity of the given qual¬ ity which can be delivered. But the conception of intelligence as arranged in levels, which levels are differentiated in terms of mental functions, or mental unit-activities, is not identical with that theory of intelligence which attempts to measure intelligence through mere quantitative measurement of each function. Binet, and many others, have shown very clearly that a person may have good memory, for example, and yet be unintelligent. Binet says:* “Just at the present time we are observing a backward girl who is developing before our astonished eyes a memory very much greater than our own. We measured that memory and we are not deceived con¬ cerning it. Nevertheless that girl presents a most beautifully classic type of imbecility.” The point is that the memory is there, but that the power to make non-predictable relationships between memories is lacking. Thus, as shown in Chapter III, the quantitative measurement of the function is quite different from the measurement of power to solve problems in terms of the function. Yet the functions do determine the levels upon which the problem-saving may occur. To handle as many levels as there are functions, however (sensation, perception, imagination, etc.), attempts a minute classification which it is relatively im¬ possible to achieve, because of the overlapping of the modes of activity. It is safer to condense the levels to three: (i) that of sensation and perception, (2) that of the image, and (3) that of the idea regarded as a symbol plus a meaning. Intentional adaptation (purposive problem-solving, thinking, learning) may take place through the relating of percepts, or of images, or of ideas. Evidences which point toward the truth of this hypothesis are numerous in popular experience, and in the existing literature of intelligence. In fact the evidences are so clear that it is surpris¬ ing that they have not hitherto been gathered up and applied to * The Development of Intelligence in Children, Vineland Laboratory, 1916; P- 43- 34 JAMES LEROY STOCKTON the better understanding of the nature of intelligence, and to methods of measurement of intelligence. The steam has been lifting the lid of the kettle for a long time, but the significance of the fact has remained obscure. II. Existing evidences that purposive intelligence is conditioned by levels based upon an analysis of mind. 1. The generally accepted idea that the abstract is “harder than the concrete”. Since concrete and abstract are only popular terms for the more technical psychological concepts of sensation, perception, memory, ideation, etc., the popular concept of degrees of intelli¬ gence is, therefore, seen to be in terms of a natural analysis of mind, stated as types of activity. 2. The popular, but contradictory, conception that pupils con¬ sidered dull because they fail in abstract subjects, prove their intelligence by success in concrete subjects. Over and over again, the child who cannot learn arithmetic, history, geography, etc., is assigned to manual training or other subjects in which concrete situations predominate, and succeeds in the new field. To say, however, that because of this success he proves his intelligence, is to go contrary to the belief that abstract subjects are harder than concrete ones. Even to say that one who fails in abstract subjects and succeeds in concrete ones has a different kind of intelligence, does not meet the point. He has also a different degree of intelligence. The pro¬ gress of humanity, all the higher life of man, depends upon the control of the abstract. A civilization based mainly upon the con¬ crete would be a civilization set back indefinitely. A person who lives mainly in the concrete is a person who has not the intelli¬ gence to enter fully into- the life of the race to which he belongs. He has some intelligence, but it is only a limited intelligence. He lacks certain levels of ability which are possessed by the mind more capable of abstraction. MODERN METHODS OF MENTAL MEASUREMENT 35 3. Courses of study in institutions for the feeble-minded. The predominating type of material is perceptual. Manual training, and all of these subjects of instruction which tend to feature predominantly the concrete, form the bulk of the curricu¬ lum. Only the most elementary abstract work is attempted. (Thought work used consistently as pre-requisite to construc¬ tion, could, and often does, raise the level of intelligence re¬ quired by manual training, and make it a valuable study for mod¬ ern schools. Then, however, the feeble-minded do not succeed in it so well.) 4. Clinical descriptions of typical feeble-minded persons. These nearly always show the tendency to arrest in the terri¬ tory of the concrete More than that they show that in concrete work such cases are, sometimes and even often, the equals or even the superiors of more intelligent subjects. That this is so, constitutes one of the most significant facts confirming the theory of intelligence herein advocated, since it shows that on the per¬ ception (concrete) level, high and low intelligence are much closer together than they are on the more abstract levels. Below is Doll’s account of a typical feeble-minded case. The reader is asked to note how the concrete is emphasized in this case, both in the results of the mental tests, and in the subject’s ability irf manual and industrial work. Doll: Clincal Studies in Feeblemindedness, Badger, 1917, pp. 81-89. “Donald, born 4/14/95, was first examined 3/5/10 at the age of 14.9. By Goddard’s 1910 revision of the B-S scale his mental age was 9.6 years. He passed all the tests at years VI and VII, failed memories at VIII and at IX, passed months and money at X, and absurdities at XI. Absolute retardation amounted to 5.3 years, relative retardation, 36 per cent. I. Q. was 64, and gave rise to a diagnosis of feeblemindedness, and a classification of middle grade moron. . . . Only extended and well directed conversation makes one conscious of his mental de- 3< 5 JAMES LEROY STOCKTON ficiency; then, a poverty of ideas, a lack of originality, limited information, and vague comprehension of abstract relations are apparent. But these are subjective impressions of which most visitors who interview him seldom become aware. They stand out more definitely and clearly under observation in standard situations. ... A formal pedagogical examination was not made, but school reports are now available. These show that he at¬ tended an orphan asylum school for two years, but made no appreciable progress. Furthermore, in spite of the exceptional advantages offered by the school department of The Training School, with its intensive and extensive individual teaching, he has never been reported as being able to do better than poor first-grade academic work. In music, and in manual and indus¬ trial work, he came to be one of the ablest of all the pupils. In particular he did well as a farm hand and learned to handle machinery, and to work with comparatively little supervision. He played well on the bass horn, both band and solo work, and al¬ though he was somewhat careless he had the reputation of being, under supervision, ‘the finest industrial worker in the school’. . . . Donald was examined by the writer 5/27/15, using Goddard’s 1911 revision of the B-S scale. The result showed a mental age of 9.6, which was identical with the first and four succeeding examinations by different examiners. In these repeated tests he showed some losses and some compensating gains over the earlier tests but the gross results have always been identical. He passed all tests up to year IX. At X he failed to make change, saying that three cents from twenty gives sixteen, seven from twenty- five cents gives seventeen, and six from twenty gives eighteen, with the actual money before him. As an independent member of society he would be dependent upon the honesty of merchants or the kindly financial assistance of friends. At year X he ex¬ hibited only hazy knowledge of the pieces of money above one dollar (although he had had ample opportunity to know money values), failed in the abstract comprehension tests, and in con¬ structing a sentence. At year 1 1 he succeeded with the rhymes, but missed all the other tests of that year. At twelve he passed only the suggestion test, and that in a manner to merit discount MODERN METHODS OF MENTAL MEASUREMENT 37 on the basis of previous experience and memory. His failure in these tests could not be said to be due to lack of scholastic or other training, for he had been pressed to learn all that his men¬ tal ability enabled him to assimilate. . . . Thus all experience and observation with Donald confirm the diagnosis made in 1910. At the end of five years of intensive training in all fields of learn¬ ing his mental capacity is the same as at the first examination. This case is typical of the milder forms of high-grade defect frequently met with in institutional experience.” 5. Evidence drawn from the construction and the application of certain intelligence tests. The evidence appealed to here will be that which shows that the power of the so-called “performance” material to differen¬ tiate mental age tends to decrease above the age of about eight years, and to reach its limit about the age of twelve years. By “performance” material is meant those tests which utilize con¬ crete material and appeal mainly to sensation and perception. Form-boards, picture puzzles, etc., are typical examples, although the variation in the field is practically unlimited. A. ILLUSTRATION FROM THE BINET TESTS.* Most of the tests in the early years are either perceptual as in III ( 1 ) , 111(2), 111(3), IV(i), IV (2) , etc., or they are repro¬ ductive of something which has been picked up through the ex¬ perience of much repetition and reproduced from memory. Ex¬ amples of the latter are III (4), III (5), etc. But it is to be noted that such material decreases upward through the years, more abstract material is added, and more immediate solution of new problems is called for. By the age of ten the concrete material is practically gone except for X(3) (designs), and X(A1.3) (Healy-Fernald Puzzle A) ; and the problem with the designs draws heavily upon image states as well as upon percep¬ tual states. It is true that in year XII one finds the Ball and Field problem which might be classed as a performance test; but the scoring in this year requires “superior plan”, which means *Terman, The Measurement of Intelligence, Houghton-Mifflin Co., 1916. 38 JAMES LEROY STOCKTON that a thoroughly logical and complete abstract conception must precede the performance. B. ILLUSTRATION FROM THE DE SANCTIS TESTS. f These tests constitute a graded series. Assuming that the correct materials are present, a rough notion of the procedure can be obtained from the following: 1. Give me a ball. 2. Which is the ball you gave me? 3. Do you see this block of wood? Pick out all the blocks like this from the pile on the table. 4. Do you see this block? (a cube). Point out a figure on the form chart that looks like it. Take this pencil (or pointer) and point out all the squares on the chart as fast as possible without missing any, taking the figures line by line. 5. Here are some more blocks like those you have pointed out on the chart. Look at them carefully and tell me (a) how many there are, (b) which is the largest, (c) which is the far¬ thest away from you? 6. Do large objects weigh more or less than small objects? Why does a small object sometimes weigh more than a large one? Do distant objects appear larger or smaller than near objects? Do they only seem smaller or are they really smaller? Determination of the degree of mental deficiency in accord¬ ance with the tests. 1. If the subject does not pass the second test the mental de¬ ficiency may be considered of a high degree. 2. If the subject cannot go beyond the fourth test, or if he makes many mistakes or is very uncertain in the fifth, the mental deficiency may be considered of a medium grade. 3. If the subject succeeds in five tests but finds the sixth diffi¬ cult, the mental deficiency may be considered of a slight amount. 4. Finally, if the sixth test is completed without mistakes, the subject may be said to present no mental deficiency. f De Sanctis, Mental Development, etc., Journal of Educational Psychol¬ ogy, 2, 1911. MODERN METHODS OF MENTAL MEASUREMENT 39 Note (i) how the work in this series begins on the perceptual level in very uncomplicated form; (2) how the perceptual is gradually complicated; and (3) how the perceptual gradually gives way to the symbolic; and (4) how finally, in the directions for determining the degree of mental deficiency, the decision rests absolutely upon the ability to climb this ladder from the percep¬ tual to the symbolic. C. ILLUSTRATIONS FROM MATERIAL UTILIZED BY PINTNER AND PATTERSON IN “a SCALE OF PERFORMANCE TESTS” (APPLETON ’ll). Examination of these graphs makes it clear at once that be¬ tween five or six years, and nine and ten years, mental ages are fairly well, and in many cases very well, discriminated ; but about ten the curves show a growing tendency to flatten out and to continue upon a plateau. By the age of twelve this tendency has gained such power that the graphs show little differentiation above that point, and where differentiation is shown by the graphs in years thirteen or fourteen, the experience of at least some of the users of the tests has been that results are not likely to be very reliable in those areas. There is at least one exception, among the graphs, to the con¬ clusion just reached. The reference is to the Knox Cube Test (Graph 27). This test shows better differentiation which may be referred to the fact that the discerning and holding in mind for repetition, of the increasingly complex series of responses, utilizes more than do the other tests powers which are superior to mere sensation or perception. When one looks at the amazingly uniform tendency of per¬ formance tests to reach the limit of their differentiating power at a point roughly shown in the graphs, one must feel that it is probably more than a coincidence that a mental age of ten or twelve for adults has usually been chosen by intelligence experts as the dividing line between normality and feeblemindedness. It seems probable that performance test standarizations have, per¬ haps unwittingly, established the approximate point where ab¬ straction must gain the ascendency, or subnormality become ap¬ parent. Graphs from “A Scale of Performance Tests,” Pintner and Patterson (Appleton, 1917). The numbering follows the original text. /V /ir Graphs from “A Scale of Performance Tests/' Pintner and Patterson (Appleton,, 1917). The numbering follows the original text. Graphs from “A Scale of Performance Tests/'' Pintner and Patterson (Appleton,, 1917). The numbering follows the original text. 44 JAMES LEROY STOCKTON Graphs from “A Scale of Performance Tests," Pintner and Patterson (Appleton, 1917). The numbering follows the original text. MODERN METHODS OF MENTAL MEASUREMENT 45 Graphs from “A Scale of Performance Tests/'’ Pintner and Patterson (Appleton, 1917). The numbering follows the original text. 4 6 JAMES LEROY STOCKTON Graphs from “A Scale of Performance Tests/' Pintner and Patterson (Appleton, 1917). The numbering follows the original text. MODERN METHODS OF MENTAL MEASUREMENT 47 Graphs from “A Scale of Performance Tests/' Pintner and Patterson (Appleton, 1917). The numbering follows the original text. JAMES LEROY STOCKTON 48 Graphs from “A Scale of Performance Tests " Pintner and Patterson (Appleton, 1917)* The numbering follows the original text. MODERN METHODS OF MENTAL MEASUREMENT 49 Graphs from “A Scale of Performance Tests/' Pintner and Patterson (Appleton, 1917). The numbering follows the original text. 50 JAMES LEROY STOCKTON Graphs from “A Scale of Performance Tests/' Pintner and Patterson (Appleton, 1917). The numbering follows the original text. hJu-mb&h MODERN METHODS OF MENTAL MEASUREMENT 51 D. ILLUSTRATION FROM PERFORMANCE TEST MATERIAL DEVELOPED BY HEALY. The Healy performance tests show tendencies similar to the other tests of the same type. However, the main use made of Healy’s work here will be as a basis for discussion of the relative failure of adults with performance material, and the signifi¬ cance of this fact to the theory of intelligence levels. The fol¬ lowing quotation, beginning on page 200 of the monograph, “A Pictorial Completion Test”,* is in point: “The older individual is prone to meet a simple situation with the idea that there must be something back of it. . . . The ‘might be’ of the adult with his greater stock of ideas is very rarely heard from the child. ... Of course the chicken ‘might be’ jumping at the cat, or at the bird in the cage. The greater ex¬ perience of adults led them to perceive many more possibilities in the situation than the child sees. It may be this, rather than any conscious attempt at criticism which leads the adult to go much farther than taking the picture at its barest face values.” This all means that the normal adult is inclined to inject ab¬ straction into the situation, and to refuse to deal exclusively with the simple concrete which is before him. He puts in much more than he sees. He does poorer work on the tests because his mind really works better. If he cannot put in the extra abstraction, he is not a normal adult, his mind is retarded on the level of the concrete, the predominating level of the child-mind. Below is a table based upon examination of 95 college people with the Healy Picture Completion Test. THE WELLESLEY DATA*}* I. Cases with no errors Wellesley 26% Private School 30% Delinquents (B Group) 33% Delinquents (A Group) 40% ^Psychological Review, XXI, 3. fPsychological Review, XXI, 3. 5 2 JAMES LEROY STOCKTON II. Percentage of total errors to pieces placed Wellesley 21.7% Private School 15.0% Delinquents (B Group) 10.0% Delinquents (A Group) 6.0% III. Percentage of total errors illogical Wellesley 64.0% Private School 50.0% Delinquents (B Group) 40.0% Delinquents (A Group) 33.0% The evidence of poorer work on the part of the college students in the strictly perceptual part of the problem is here very evi¬ dent. If the suggested reason for it is the true one, however, the poor showing is a recommendation rather than otherwise. Even the high per cent of illogical error as judged in perceptual terms, becomes logical when judged in abstract terms, and therefore be¬ comes a recommendation rather than a fault. These data, there¬ fore, are understandable on the theory that the one who can get the most out of a perceptual test is the one who has not developed beyond the perceptual level. He does not have the great stock of abstract ideas to bother him, and consequently he saves time by direct and naive solution of the concrete situation. Perhaps the best way to make a performance test indicate truly the intelli¬ gence of the adult "would be so to regulate it that the number of original, but proved logical, solutions would determine the score. Then the adult would not be penalized for his higher type of intel¬ ligence as he now is in such tests. (Pintner and Patterson, work¬ ing with the Knox tests with children, were obliged to set higher limits of achievement and time than those used by Knox with adults.) — See discussion at several points in “A Scale of Per¬ formance Tests”, by Pintner and Patterson. (Appleton, 1917.) E. ILLUSTRATIONS FROM STUDIES DIRECTED TOWARD THE DETERMINATION OF THE TYPE OF MENTAL FUNCTION POSSESSED BY THE FEEBLEMINDED. A very good illustration is found in the excellent study by Cyrus D. Mead, Ph.D., Teachers’ College Contribution to Edu- MODERN METHODS OF MENTAL MEASUREMENT 53 cation, No. 76, on “The Relations of General Intelligence to Cer¬ tain Mental and Physical Traits". The reader is referred to Dr. Mead’s monograph for the conclusive data back of the assertions made in the following quotation concerning the relative percep¬ tual and memory powers of the feebleminded and the normal child. Page 78, line 3 : “As a practical suggestion from the above data, and with a firmer conviction after six years of experience in the education of hundreds of mentally defective children, the au¬ thor would offer the point that in the ability to perceive and to memorize defective children do better than in any other of the purely mental traits. It makes less difference with these children whether the material has relationship than it does with normal children. Memory seems to be a characteristic in itself, native perhaps. It is a common occurrence to have defective children call their teacher’s attention to any slight change in the latter’s dress. The powers of perception and memory then should be used to the utmost in the education of these children. The most practical contribution made by Miss Norsworthy in her study is quoted: ‘To speak of (defectives) them as being equally defi¬ cient in all the mental powers is false. . . . From the point of view of the psychologist and the educator it is fully as important to know that the (defective’s) perceptive powers are almost two and a half times as strong and accurate as his intellectual powers, and almost half as strong again as is his powers of memory, as to know that he is weaker than the ordinary child in all of these particulars.’ ” Three things here are evident : ( 1 ) that defective children do not possess the higher mental functions to the degree that these functions are possessed by normal children; (2) that they possess memory and perception to a very considerable degree; and (3) that they tend to fail in the power to note relationships between the memories and percepts which they really possess. Another illustration may be drawn from the pamphlet by Knox on “Alien Mental Defectives” (Stoelting, Chicago). In this pamphlet is a study entitled, “A Comparative Study of the Imaginative Power in Mental Defectives”. Again the reader is referred to the article itself for the data which are too detailed to 54 JAMES LEROY STOCKTON reproduce here; but the conclusions are significant. (The test was the common “Ink Blot” test.) Dr. Knox says: “(i) It is apparent from a study of the tables that there are no Jules Vernes among the twenty-five defectives, at least, and, as compared to the twenty-five normals, there is very little abil¬ ity to draw mental pictures from commonplace or amorphous ob¬ jects. (2) The associations among the defectives are for the most part not logical. ... (4) The reaction-time was nearly twice as long in the defectives as in the normals. ... (5) Tests of imagination and the average reaction-time to questions may be valuable points to consider when dealing with mental defectives from a diagnostic standpoint.” This quotation, and its supporting data, reinforce the point of the previous quotation that the imaging ability of the feeblemind¬ ed is less than their perceptive ability, and that their logic, or judgment, is the least of all of their abilities, F. ILLUSTRATIONS FROM SUCCESS AND FAILURE IN ABSTRACT AND CONCRETE SUBJECTS OF INSTRUCTION. In an article by Cummins in “The Journal of Educational Psychology”, October, 1919, there appears a comparison of “bright” and “slow” pupils. In the process of this study there is developed the following with relation to the relative difficulty of studies : “By dividing the number of cases in which high marks were received, by the number of cases in which low marks were re¬ ceived, the ratios thus obtained give us a fair picture of the rela¬ tive difficulty of each subject. Arranging the subjects in the or¬ der of these ratios from the highest to the lowest, we have the fol¬ lowing array : Physical Training . 14-67 Arts (Domestic and Fine) . 5.25 Shop (Manual Training, etc.) . 3.00 English and History . 1.56 Modern Language . 1.42 Science . .92 Ancient Language . .46 Mathematics . .19 MODERN METHODS OF MENTAL MEASUREMENT 55 Thus there appears an almost perfect gradation all the way from the subject which is almost wholly a matter of ideo-motor coordination, to the subject which involves the largest amount of abstract thinking. The only possible exception is that of an¬ cient language which should no doubt have occurred in the array following the modern languages.” It is true that, since this relationship of studies is based upon marks received, the reason for the greater number of high marks received in physical training, etc,, and the frequency of low marks in mathematics, etc., may have been the different marking standards of different teachers. But it is improbable that the sequence in the array from concrete to abstract would have been anywhere nearly so perfect unless it was at least somewhat deter- minded by the real character of the subjects as well as by the per¬ sonal equation of the person giving the marks. The conclusion from the data presented that abstract studies are relatively harder (require more intelligence) is a relatively safe one. Other illustrations of this point might easily be produced. Some material taken from “The Illinois Survey” (Published 1917 by the Illinois State Teachers’ Association), will suffice. Table VIII — Sec. 10 Median Proportion of Pupils in Each Grade, Page 124, Reported as “Finding Difficulty in Completing Required Work”. No. of Teachers Median Proportion of Grade Reporting Pupils “Finding Difficulty”. I . 192 6%-io% II . 124 6%-io% III . 102 n%-i5% IV . 1 16 6%-io% V . 1 12 6%-io% VI . 1 14 6%-io% VII . hi 6%-io% VIII . 109 6%-io% Note. — Because of certain reasons the extra percentage in grade III is not considered especially significant. In Terman’s “The Measurement of Intelligence”, p. 78, there is a table showing that in an unselected group of persons of a reasonably large number, the intelligence quotients of the lowest ten per cent will be 85 or below. It is reasonably safe to sup¬ pose that the children under consideration by these Illinois teach- 56 JAMES LEROY STOCKTON ers represented such an unselected group, and that those reported as “finding difficulty” were largely those of approximately 85 I. Q. or below, since the 6 per cent to 10 per cent reported would be constituted of just about the low I. Q.’s in question. The fol¬ lowing table from the same survey gives further light upon the matter. Table IX — Sec. i, Page 125 Subjects in Which Pupils Find it Difficult to Complete the Required Work. 34.60% of teachers reporting 18.15% of teachers reporting 17.46% of teachers reporting 17.26% of teachers reporting 13.84% of teachers reporting 12.79% of teachers reporting 10.70% of teachers reporting name reading name arithmetic name language name geography name spelling name grammar name history On page 143 of the same book is found the following: “The subjects in which the greatest difficulty is experienced, varies from grade to grade. In general, arithmetic may be looked upon as the most difficult subject as measured by the standard represented in Table IX (teachers’ judgments), and the difficulty of this subject is sustained throughout the grades, from the third to the eighth.” It is clear that these teachers found the poorest 10 per cent of the children (almost certainly children of low I. Q.) having trouble with the abstract subjects. Not a single one of the more perceptual subjects is mentioned. Again the result might be due to excessive requirements in the subjects named, and the light requirements in the other subjects; but the chances are all in favor of the assumption that the type of subject, abstract or concrete, is at least partially the determining factor. Another table from the same survey is interesting in this connection. Something of the same progression from concrete to abstract is seen in Table XVII. The assumption is possibly a fair one that teachers would, in matters of promotion, disregard those sub¬ jects which they do not consider to be very good tests of a child’s general ability. In this same survey there is a study of “Some Exceptional High School Pupils in Illinois” by E. E. Jones. He shows that MODERN METHODS OF MENTAL MEASUREMENT 57 Table XVII — Page 140 Subjects Disregarded in Determining Promotion. Subject Music . Drawing . Writing . Physiology and Hygiene Manual Training . Physical Training . Spelling . Arithmetic . Reading . History . Language . Geography . Grammar . Proportion of 1407 Teachers Reporting Subject as Disregarded 67.3 65.4 31-4 10.2 9.1 9-1 8.1 2.8 2.8 2.7 2.0 1.9 9-5 these pupils did all round good work in the grades and did not drift toward any particular line of work. They were not pushed early into manual training or other hand work. They had gen¬ eral ability; and this general ability showed in the high school as well as in the grades. The pupils tended to be good in every¬ thing that they undertook. And yet the author says that he found no reason why these persons excelled. Is it not clear that they excelled because they had good general endowment — in ability to deal with the abstract as well as in ability to deal with the concrete ? CHAPTER V The Fundamental Nature of Intentional Adaptation (Continued). I. Original quantitative studies. i. In upper school grades. Attempts made by the writer to test the hypothesis of levels in intentionally controlled intelligence have been guided by the conclusion that if the theory in question is true, then the achieve¬ ment of high and low intelligence should be nearest together on the perceptual level where all tend to be more equally endowed, and farthest apart on the symbol level, upon which low intelli¬ gence finds it hard to act at all. (To leave out the image level accents the contrast of the extremes.) In this upper grade study the first step in quantitative deter¬ mination was that of ascertaining the general intelligence of a chosen group so that the result could be used as a criterion for checking further work. For this purpose the Binet-Simon tests were chosen as the best available instrument. It is true that these tests themselves show a gradation from perceptual material to symbol material, and that, at first glance, it might seem that to use them as a criterion in attempts to prove the existence of levels based upon the same principle, would be to reason in a circle. On the contrary, the exact reverse is the case. When the authors devised these tests they made use of a purely trial and error method. They experimented with very numerous “stunts” of all descriptions and the separate tests really located them¬ selves. They fell into certain relative positions and relationships because as a result of their fundamental nature they could oc¬ cupy no other positions and relationships. After they had as¬ sumed those relationships, and so had become a scale for the measurement of intelligence, that scale was checked by criteria MODERN METHODS OF MENTAL MEASUREMENT 59 of all kinds, such as estimates of intelligence, school work, school progress, experience in life, etc., etc. ; and it is now generally admitted to be the best instrument for getting at an approxima¬ tion to exact quantitative measurement of intelligence. If one accepts the scale as it is and examines it with the purpose of dis¬ covering the factor responsible for the self-arrangement of the individual tests, one is forced to conclude that this responsible factor lies in differences in amounts of perceptual and symbolic material utilized at various levels. Thus these tests themselves supply a certain amount of confirmation of the hypothesis for which proof is sought, and they have already been so cited. But one can go farther. For example, if one makes brick and gets an especially excellent quality, he may examine all con¬ ditions of the process and try to decide upon the factor respon¬ sible for the excellence. Then he can vary that factor, compare with the original results, and so test his opinion as to the factor’s responsibility for the excellence. The intention has been similar in the present instance. The start is made on the theory of the responsibility of the proportions of the perceptual and symbol materials, those proportions are varied, and the results are ex¬ amined for light upon the theory. An abbreviated form of the Binet-Simon tests (the starred tests of the Stanford Revision) was given to 364 children in grades four to eight, inclusive, of a normal training school. Table I shows the raw data of this study. Table I Original Data: Abbreviated Binet and Teachers’ Estimates of Intelligence. Case Born Eighth Grade. Tested M.A. 1st Est. 2nd Est 1 10/18/03 3/ 4/i9 14- 2.5 5 4 2 12/24/04 2/25/19 14- 7-5 4 4 3 11/16/04 2/25/19 15- 4-5 4 4 4 12/29/05 2/28/19 16- 0 4 4 5 1/26/05 2/26/19 1 7- 4.5 3 3 6 9/14/03 2/25/19 15-10.5 3 3 7 10/17/02 3/ 4/i9 13- 0 6 5 8 1 2/ 4/03 3/ 4/i9 13- 9-5 6 5 9 5/ 6/05 2/26/19 15- 2 4 3 10 8/23/04 2/25/19 16- 7-5 4 3 11 6/13/03 2/27/19 14- 8 4 5 12 9/ 9/03 2/26/19 15- 9-5 5 4 13 1 1/25/03 3/ 4/i9 1 2- 7-5 6 5 6o JAMES LEROY STOCKTON Table I (Continued) Case Born Eighth Grade Tested M.A. 1st Est. 2nd Est. 14 1/11/05 2/26/19 15-10.5 1 3 15 6/28/01 3/ 4/i9 11- 4 6 6 16 3/ 1/04 2/28/19 13- 9-5 4 4 1 7 5/19/05 2/27/19 13- 7.5 3 4 18 3/ 6/04 2/28/19 15- 4-5 3 4 19 9/17/03 2/27/19 13- 7-5 4 4 20 4/ 9/03 2/25/19 12- 8 5 5 21 8/ 2/02 3/ 4/i9 13- 7 6 5 22 7/17/05 2/28/19 15- 5-5 4 4 23 3/30/05 2/26/19 14- 5 4 4 24 11/16/04 3/ 4/i9 13- 2 4 5 25 10/28/01 3/ 4/i9 11- 4-5 5 6 26 8/21/03 2/28/19 12- 6 5 5 27 3/ 9/03 3/ 4/i9 12- 8 6 5 28 3/18/05 2/25/19 13- 1.5 3 4 29 9/18/05 2/26/19 16- 0 1 I 30 10/ 1/03 2/27/19 I3-H.5 4 4 3i 5/14/05 2/26/19 14- 5 4 4 32 5/18/03 3/ 4/i9 12- 7-5 6 6 33 7/20/04 2/28/19 13- 9 4 4 34 11/24/04 3/ 4/i9 16- 7-5 3 3 35 1 2/ 4/02 2/26/19 13- 1-5 4 4 36 4/ 2/02 3/ 4/i9 13- 3 5 7 7 37 8/29/04 3/ 4/i9 14- 2 4 4 38 2/18/06 2/25/19 15- 6 1 1 39 2/ 1 2/0 1 3/ 4/i9 15- 3 5 6 40 10/ 2/04 3/ 4/i9 14- 3 5 5 4i 11/ 8/05 3/ 4/i9 15- 3 4 4 42 1/29/06 3/ 4/i9 14- 4-5 4 4 43 11/ 2/00 4/ 9/i9 13- 3-5 6 6 44 2/ 5/06 3/ 4/i9 16-10.5 4 3 45 11/ 2/04 3/ 4/i9 14- 9 3 3 46 6/16/06 3/ 4/i9 18- 1.5 2 1 47 1 / 19/05 3/ 4/i9 16- 7-5 3 4 48 6/ 8/04 3/ 4/i9 15- 9-5 4 4 49 2/ 8/06 3/ 4/i9 15- 4-5 4 4 50 8/ 2/04 3/ 4/i9 14- 3 4 3 5i 12/25/02 3/ 3/i9 15- 8 6 6 52 12/15/04 3/ 4/i9 13- 2 5 4 53 7/1 1/05 3/ 3/i9 14- 7-5 4 4 54 3/22/05 3/ 4/i9 14- 1.5 6 6 55 8/14/03 3/ 4/i9 16-10.5 4 4 56 5/29/04 3/ 4/i9 13- 8.5 6 6 57 2/15/07 3/ 4/i9 16- 1.5 2 2 58 10/13/05 3/ 4/i9 17- 4-5 2 2 59 10/ 6/05 3/ 4/i9 13-n 5 5 60 8/ 4/03 3/ 4/i9 15- 1-5 5 5 61 12/12/02 3/ 4/i9 14- 6 6 6 62 1 2/ 9/03 3/ 4/i9 13- 9-5 5 5 63 1 1/23/02 3/ 4/i9 12- 8.5 6 6 64 3/ 2/05 3/ 4/i9 12- 6 4 4 65 5/20/05 3/ 4/i9 14- 7-5 4 4 66 12723705 3/ 4/i9 12- 8.5 4 4 67 2/ 22/04 3/ 4/i9 15- 6 4 4 68 6/24/07 3/ 4/i9 15- 4-5 4 4 Case 69 70 7 1 72 73 74 I 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 3i 32 33 34 35 36 37 38 39 40 4i 42 43 44 45 46 47 MODERN METHODS OF MENTAL MEASUREMENT 61 Table I (Continued) Eighth Grade Born Tested M.A. 1st Est. 2nd Est. 11/ 6/04 3/ 3/i9 14- 4-5 4 4 5/22/04 3/ 4/i9 16- 0 5 5 10/ 4/04 3/ 4/i9 11- 8 5 5 2/18/04 3/ 4/i9 13- 6 5 5 9/15/05 3/ 4/i9 14- 5 4 4 3/11/06 3/ 4/i9 Seventh Grade 16- 0 4 4 6/ 9/05 3/ 4/i9 16- 0 4 4 9/20/05 3/ 4/i9 14- 10.5 4 4 3/ 7/o6 3/ 4/i9 15- 9 3 2 1/ 1/04 3/ 4/i9 14- 0.5 4 4 5/13/05 3/ 4/i9 16- 0 3 3 10/12/02 3/ 4/i9 14-10 4 3 11/ 9/05 3/ 4/i9 14- 7-5 3 3 11/23/03 4/11/19 13- 2 5 5 6/ 4/05 3/ 4/i9 15- 6.5 3 3 7/23/07 4/11/19 16- 1.5 3 3 1/20/05 3/n/i9 15- 7-5 4 5 1 2/ 7/05 3/ 4/i9 16- 0 4 3 9/24/06 3/ 4/i9 15- 4-5 3 2 1 2/ 8/03 3/11/19 14- 3 5 5 12/15/04 3/ 4/19 14-10.5 4 5 3/ 7/05 3/ 4/i9 14- 7-5 4 4 1 2/ 8/05 3/ 4/i9 18- 9 2 2 2/29/04 3/ 4/i9 9- 4 7 7 11/ 9/04 3/ 4/i9 13- 3-5 4 4 7/13/04 3/ 4/i9 16- 0 5 5 8/13/04 3/11/19 12-11.5 4 4 1 2/ 16/05 3/ 4/i9 14- 6.5 4 4 6/17/05 3/ 4/i9 13- 6.5 4 4 9/29/05 3/ 4/i9 16- 1.5 3 3 1/22/07 3/ 4/i9 14- 4-5 3 3 8/20/04 3/11/19 15- 7-5 4 5 12/20/05 3/11/19 12- 2 3 4 5/31/04 3/11/19 14- 1.5 5 5 11/16/03 3/11/19 14- 0 4 4 1 2/ 3/05 3/n/i9 15- 3 3 4 1/12/06 3/ 4/i9 13- 1.5 4 4 10/22/05 3/ 4/i9 12- 5-5 4 5 11/26/05 3/ 3/i9 16-10.5 3 4 10/23/03 3/11/19 12- 9 4 4 n/13/05 3/ 4/i9 14- 3 4 4 3/23/06 3/ 4/i9 15- 2 4 4 4/15/04 3/n/i9 13- 0 4 4 3/12/05 3/11/19 12- 2 5 6 6/22/05 3/n/i9 15- 0 4 6 9/ 2/06 4/18/19 12- 0 4 4 3/14/04 3/11/19 15- 0 4 4 7/15/05 3/n/i9 16- 0 4 4 7/15/05 3/11/19 12- 8 4 4 12/20/04 3/11/19 12-10 4 4 1 2/ 3/06 3/ 4/i9 15-10.5 2 2 10/ 4/05 3/n/i9 12-11.5 4 4 6/18/05 3/11/19 IO-IO 4 4 62 JAMES LEROY STOCKTON Table I (Continued) Seventh Grade Case Born Tested M.A. 1st Est. 2nd Est. 48 6/11/07 3/11/19 17- 4-5 2 2 49 1/ 5/06 3/ 4/i9 12- 0 4 4 50 12/17/06 3/ 4/i9 13-n 2 2 5i 10/20/03 3/11/19 11- 4 6 5 52 3/22/06 3/ 4/i9 14- 9 2 2 53 7/20/05 3/11/19 13- 6.5 4 4 54 2/13/05 3/11/19 11- 8 5 5 55 4/20/05 3/ 4/i9 11- 8 5 5 56 2/16/07 3/11/19 14- 9 3 3 57 1 2/ 8/05 3/n/i9 12- 4 4 4 58 1/11/06 3/11/19 14-10 4 4 59 7/ 4/06 3/ 4/i9 13- 3-5 3 2 60 6/ 7/06 3/11/19 15- 4-5 4 4 61 1 1/25/05 3/11/19 15- 0 4 4 62 6/13/06 3/11/19 II-IO 4 4 63 2/ 6/05 3/11/19 12- 4 4 4 64 10/19/05 3/11/19 12- 4 4 4 65 7/29/06 3/11/19 16- 3 4 4 66 4/ 3/o6 3/ 4/i9 14- 3-5 4 4 67 12/19/07 3/ 4/i9 13- 7-5 2 2 68 1/ 13/07 3/ 4/i9 16- 3 2 3 Sixth Grade 1 8/ 6/06 3/11/19 12- 4 4 6 2 7/19/04 3/11/19 II-IO 6 6 3 4/28/04 3/11/19 14- 7-5 5 4 4 6/12/06 3/27/19 13- 7-5 4 3 5 8/ 7/06 3/11/19 13- 9-5 5 4 6 7 /7/06 3/11/19 12-11.5 4 4 7 8/17/04 3/11/19 12- 4 4 4 8 1/26/05 4/11/19 12- 0 3 3 9 2/15/06 3/11/19 12- 4 5 3 10 8/ 7/07 4/11/19 16- 3 2 2 11 4/ 2/03 3/28/19 13- 4 6 5 12 12/23/02 3/11/19 12- 0 6 7 13 9/10/06 3/11/19 12- 8 4 5 14 1/ 5/06 3/11/19 12- 5 4 5 15 2/ 7/06 3/11/19 11- 7 4 4 16 4/ 4/06 3/11/19 13- 9-5 4 4 1 7 1/ 4/06 3/18/19 13- 0 5 5 18 2/ 1/07 3/11/19 11- 0 5 5 19 12/29/07 3/11/19 14- 1-5 2 2 20 3/ 1/06 3/18/19 13- 9 4 5 21 12/15/07 3/11/19 11- 6 4 5 22 1/ 5/06 3/11/19 15- 7-5 2 2 23 9/ 8/06 3/11/19 13- 4 5 4 24 4/27/08 3/11/19 15- 8 2 2 25 4/24/07 3/n/i9 16- 1.5 2 2 26 11/25/04 4/14/19 11- 4 7 5 27 9/13/05 3/11/19 9- 9 6 5 28 1/ 9/05 3/27/19 13-11 3 3 29 5/26/06 3/27:19 12-11 5 4 30 2/28/07 3/11/ 19 12- 8 6 6 3i 2/20/27 3/11/19 14- 6 1 1 32 3/ 6/06 3/25/19 12- 8.5 5 5 Case 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 5i 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 7i 72 73 1 2 3 4 5 6 7 8 9 10 11 12 13 MODERN METHODS OF MENTAL MEASUREMENT 63 Table I (Continued) Sixth Grade Born Tested M.A. 1st Est, 6/ 3/06 3/12/19 13- 5-5 3 8/ 8/04 3/18/19 12-11 4 1/16/07 3/11/19 15- 0 3 8/25/07 3/11/19 15- 4-5 1 11/ 4/04 3/24/19 14- 3 2 5/16/06 3/18/19 13-n 5 9/27/06 3/18/19 n- 5 5 6/20/05 3/21/19 12- 1 5 9/27/05 3/17/19 14-10 2 3/17/06 3/1V19 15-10.5 2 2/ 7/07 3/11/19 12- 7-5 2 1 / 10/05 3/11/19 12- 6 6 3/ 6/06 3/24/19 15- 6 4 1/27/07 3/11/19 13- 7.5 4 7/ 6/06 3/18/19 14-10 4 3/ 3/07 3/ii/i9 10- 9 4 9/16/06 3/11/19 11- 2 5 7/15/05 3/18/19 II-IO 4 5/18/07 3/11/19 14- 3-5 2 11/25/06 3/24/19 12-11.5 4 3/ 1/08 3/11/19 15- 7-5 2 5/12/06 3/31/10 15- 4-5 2 5/23/07 3/11/19 13- 9-5 3 2/ 9/08 3/27/19 10- 0 2 1/ 3/06 3/18/19 16- 7-5 2 9/30/07 3/20/19 13- 8 3 12/29/0 6 3/26/19 11- 9-5 6 5/31/06 3/27/19 12- 8 5 10/ 1/06 3/27/19 11- 4 5 7/10/07 3/24/19 II-IO 5 7/25/07 3/18/19 14- 1-5 3 9/25/06 3/20/19 12- 5-5 2 6/ 5/07 3/24/19 15- 6 5 1 1/29/0 7 3/24/19 11- 4 4 11/19/06 3/21/19 11- 4 7 10/23/05 3/27/19 9- 6 6 6/ 4/07 3/24/19 12-11.5 4 2/ 7/05 3/24/19 II-IO 6 11/10/05 3/24/19 14- 6.5 3 3/ 8/07 3/24/19 12- 4 2 10/27/04 3/24/19 10- 8 6 Fifth Grade 2/16/08 3/18/19 11- 8 3 10/ 4/06 3/20/19 12- 1.5 4 6/15/06 3/27/19 10- 9 5 3/ 4/06 5/I3/I9 10- 4 5 7/25/06 5/ 2/19 10- 2 5 9/17/06 3/27/19 11- 8 3 9/29/08 3/21/19 16- 3 2 5/11/08 3/18/19 11- 4 2 10/14/06 3/27/19 15- 9-5 4 5/ 5/o6 3/18/19 15- 1-5 3 2/ 6/06 3/27/19 12- 3-5 4 7/ 2/04 5/ 5/i9 10- 6 6 12/ 1/06 3/26/19 11- 3-5 4 2nd Est. 0\Ln Co 4^ to ^ Co Cn 4^ Cn Co Co Ca Co Co 4^ 4^- 4^- 0\4^- 4^ 4^ to <-n 4^ Cn ON Co to *0 Co to hCo t0^i4^4^CoCo tOMCoCoCoCrtCnCn to w 104^-Co 14 15 i6 1 7 18 19 20 21 22 23 24 25 26 27 28 29 30 3 1 32 33 34 35 36 37 38 39 40 4i 42 43 44 45 46 47 48 49 50 5i 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 4 5 4 4 2 3 3 6 I 3 3 3 4 4 2 4 3 4 3 3 3 3 4 3 4 4 3 3 4 6 4 3 3 5 4 3 3 4 5 5 3 5 4 5 4 5 5 5 5 4 5 6 4 3 4 5 JAMES LEROY STOCKTON Table I (Continued) Fifth Grade Born Tested M.A. 1 / 14/07 3/27/19 10- 8 10/27/04 4/29/19 11- 8 1/20/08 3/25/19 11- 0 10/ 3/06 3/27/19 10- 6 10/30/07 3/25/19 13- 6.5 4/15/07 3/25/19 13- 9 6/ 5/07 3/18/19 12-11.5 8/26/04 3/18/19 12- 7-5 2/20/09 3/25/19 15- 4-5 3/13/07 3/26/19 11- 8 3/13/08 3/18/19 11- 4 9/17/07 3/25/19 11- 0 7/ 11/07 4/30/19 11- 6 10/ 1 2/05 5/ 2/19 11- 6 1/24/09 4/30/19 13- 9-5 12/ 2/07 4/30/19 10- 9 10/28/0 7 5/ 2/19 12-11.5 8/22/05 5/ 2/19 12- 0 7/28/08 5/ 2/19 12- 2 6/19/08 5/I4/I9 11- 0 5/27/06 5/ 1/19 12- 3-5 6/13/07 4/29/19 12- 4 2/ 8/07 5/ 2/19 11- 1 3/ 1/08 5/ 3/i9 12- 1.5 8/23/07 4/30/19 10- 8 7/ 7/07 4/30/19 1 2- 9-5 7/21/08 4/30/19 11- 5 4/28/08 5/ 2/19 13- 9 1 / 10/06 5/ 2/19 13- 4 5/15/04 5/ 5/i9 9- 3 10/18/08 5/12/19 12- 3-5 9/18/07 5/ 2/19 12- 1.5 4/17/09 5/ 5/i9 14- 5 7/ 2/08 5/ 2/19 12- 0 5/19/07 5/ 3/i9 13- 5 2/ 1/09 5/ 2/19 12- 7-5 7/18/08 5/ 7/i9 11- 8 3/23/06 5/ 6/19 10- 0 7/16/06 4/29/19 11- 4 2/22/07 5/ 7/i9 n- 4-5 6/ 8/08 5/ 5/19 14-10.5 6/ 1/07 4/28/19 9-10 4/15/08 4/23/19 ii-ii*5 1/12/06 5/ 8/19 n- 3*5 4/ 3/09 5/ 5/i9 10- 8 10/ 8/06 5/ 6/19 10- 8 10/17/07 5/ 6/19 11- 8 3/ 4/08 5/ 5/i9 9-10 8/12/08 5/ 6/19 10- 0 3/29/09 4/23/19 9- 7 4/13/08 5/ 6/19 10-10 10/18/08 4/21/19 9- 6 7/10/08 5/ 2/19 11- 8 5/26/08 5/ 1/19 10- 5 2/20/08 4/28/19 10- 5 6/23/06 5/ 8/19 9- 8 1st Est. Ui 4X .fi. 4^ OV-n -tx -E>. [\ fnfn-ktn ; n Ln Ln -k. ^ -U -t^ In tO -L -U 0\4^. tO -£*■ OJ tO h Ln tO Oj tO-t^-t^Oi^i. 70 7 1 72 73 74 75 76 77 78 79 80 81 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 1 7 18 19 20 21 22 23 24 25 26 27 28 29 30 3i 32 33 34 35 36 37 38 39 40 4i 42 M0£££iV METHODS OF MENTAL MEASUREMENT 65 Table I (Continued) Fifth Grade Born Tested M.A. 1st Est, 1/ 9/08 5/ 5/i9 10- 8 5 9/30/08 5/ 2/19 17- 1.5 3 6/20/08 5/ 2/19 11- 0 3 11/19/06 5/ 7/i9 11- 3-5 4 10/ 2) 07 4/30/19 9- 7 5 2/22/08 5/ 3/i9 11- 2 4 12/30/0 7 5/ 2/19 11- 8 4 1/29/07 5/ 1/19 11- 6 4 3/ 7/08 4/23/19 10- 6 5 4/30/07 5/ 5/i9 10- 8 3 3/ 6/09 5/ 5/i9 11- 4 4 10/23/0 7 5/ 5/i9 10- 8 4 Fourth Grade 10/ 5/08 4/23/19 11- 5 5 10/27/08 4/29/19 9- 3 5 3/29/09 4/24/19 12- 6.5 2 4/ 9/08 4/28/19 11- 8 3 9/28/08 4/23:19 13- 3-5 2 8/23/08 4/21/19 11- 0 4 11/21/08 4/21/19 16- 4.5 1 11/11/07 5/ 7/i9 13- 0 3 4/29/09 4/21/19 12- 7.5 3 1/25/08 4/29/19 11- 1 6 3/31/08 4/23/19 9- 9 6 6/ 5/08 4/30/19 12- 2 2 12/30/07 4/23/19 16- 0 2 5/19/07 5/I7/I9 13- 0 2 7/12/08 5/ 7/i9 11- 0 3 12/13/06 5/ 6/19 9- 3 5 11/27/08 5/ 6/19 9- 3 5 2/22/10 5/ 7/i9 13- 6.5 1 5/ 3/09 5/ 5/i9 10- 4 4 2/12/07 5/I3/I9 11- 0 6 5/18/08 4/22/19 10- 2 6 5/ 4/07 4/29/19 9- 6 6 12/ 9/08 5/ 7/i9 14- 9 4 7/24/08 5/ 7/i9 11- 0 4 12/ 5/06 4/29/19 8- 6 5 8/26/04 4/21/19 10- 0 7 12/21/06 4/22/19 8- 9 7 10/ 6/07 4/23/19 8- 6 5 10/ 6/07 4/23/19 8- 6 6 9/ 7/08 4/29/19 12- 1.5 5 1/22/08 4/29/19 10- 4 5 5/14/08 4/22/19 9-11 4 6/13/09 4/23/19 n-11.5 4 8/27/09 4/22/19 9- 4 4 7/ 6/06 4/29/19 9-1 1 5 5/23/09 4/21/19 9- 6 3 4/22/09 4/21/ 19 11- 0 3 10/12/09 4/18/19 10- 8 3 5/ 8/08 4/14/19 10- 7 4 8/13/09 4/i7/i9 11- 6 2 1/ 9/08 4/22/19 9- 7 4 10/12/07 4/15/19 8- 9 6 2nd Est. 5 2 4 5 6 6 4 4 5 7 7 5 6 4 4 4 4 4 4 3 3 3 4 2 4 7 66 JAMES LEROY STOCKTON Table I (Continued) Case Born Fourth Grade Tested M.A. 1st Est. 2nd Est, 43 10/ 16/08 4/16/19 12- 5-5 4 3 44 2/16/09 4/15/19 8- 8 6 6 45 12/10/08 4/15/19 11- 0 4 4 46 5/24/10 4/16/19 10- 4 6 6 47 11/ 2/09 4/15/19 10- 7 6 6 48 7/11/08 4/15/19 9-1 1 5 5 49 10/29/08 4/21/19 10- 1 3 3 50 1/15/09 4/17/19 11- 7-5 3 3 5i 9/12/09 4/30/19 10-10 4 5 52 7/ 2/08 4/30/19 10- 8 4 4 53 8/15/09 4/I7/I9 13- 3 2 2 54 12/13/09 3/26/19 12-10 2 2 55 4/29/09 4/21/19 10- 8 4 3 56 4/19/09 4/ 14/ 1 9 9- 6 4 4 57 12/29/09 4/17/19 10- 9 2 .2 58 3/11/09 4/18/19 9- 6 3 2 59 12/12/08 4/18/19 10- 4 4 3 60 5/ 5/io 4/16/19 10- 2 5 5 61 7/1 1/09 4/i7/i9 8- 9 5 5 62 11/ 6/05 4/15/19 11- 0 7 7 63 6/29/08 4/17/19 11- 5 4 4 64 2/27/08 4/16/19 10- 1 4 5 65 11/11/07 4/21/19 9- 6 4 4 66 10/10/09 4/16/19 9- 9 5 5 67 2/ 3/09 4/16/19 9- 9 4 5 68 5/30/09 4/21/19 10- 1 4 5 Table II shows the distribution of the resulting intelligence quotients. (See page 79 for reason for selection of interval.) Table II Distribution of 364 Binet I. Q.’s. — to 59 60 to 75 76 to 91 92 to 107 108 to 123 124 to 139 140 — 0 15 83 137 93 23 13 This table shows that the cases used constituted a very sym¬ metrical distribution. This distribution was entirely the result of chance selection. The group below 60 I. Q. was not represented, of course, for intelligence of that grade is usually eliminated from the public school. The slight preponderance of high I. Q.’s was, perhaps, to be expected in the type of school which these children attend. The work of determining the intelligence quotients was very carefully done. The tests were given partly by the writer and partly by other examiners, all of whom were trained by him. A MODERN METHODS OF MENTAL MEASUREMENT 67 common exact procedure was rigidly followed, the responses of the children were written down verbatim, and the writer rescored all papers as carefully and consistently as possible. Where known irregularities of any kind developed the test was discarded. Previous experience in several schools led to a very careful checking of the chronological ages of the children before such ages were used as a basis for the computation of intelligence quo¬ tients. It is a common thing in any public school to find error in from 10 per cent to 15 per cent of records of chronological ages, even when such ages have been furnished by parents. This matter was followed up very carefully, the ages were obtained from two or three different angles, discrepancies noted, and per¬ sonal work done to establish the facts. After the intelligence quotients had been computed on the basis of the rescored papers, and the rechecked chronological ages, these quotients were checked by correlation with teachers’ estimates of intelligence. For original data on estimates see Table II. The estimates had been obtained previous to the giving of the Binet tests. The procedure used in securing the estimates utilized the following instructions: In estimating intelligence you are asked to grade on a scale of 1, 2, 3, 4, 5, 6, 7, as follows: 1 = Very superior 2 = Superior 3 = Somewhat above average 4 = Average 5 = Somewhat below average 6 = Inferior 7 — Very inferior Be sure to take age into account. Compare the child with what you consider to be the average for children of his own age. Avoid grouping your estimates in one or two groups. Ordi¬ narily the 4 group (average) will be the largest single group. In the majority of classrooms group 5 should be approximately equal to group 3, group 6 equal to group 2 , and group 7 equal to group 1. Your estimates will be held as absolutely confidential, therefore do not hesitate to place the child in the group where he belongs, however low that may be. 68 JAMES LEROY STOCKTON The teachers did not know that they would be asked to make these estimates again; but about one week later they were asked to repeat the process, rating each child with no opportunity for comparison with the former rating. Then Pearson correlations were made for each grade (i) between Binet I. Q. and the grade teacher’s first estimate of intelligence, and (2) between Binet I. Q. and the same teacher’s second estimate of the same pupils. The results of these correlations are shown in Table III. The co¬ efficients are relatively high, due perhaps (1) to the care with which the I. Q.’s were determined, and (2) to unusual ability in estimation on the part of the teachers. Table III Correlation of Binet I. Q. with Teachers’ Estimates of Intelligence. Grade 1st Est. 2nd Est. 8 .70 •75 7 •77 .68 6 .70 .69 5 .66 .68 4 .72 •7 1 All Grades .69 .69 The probable error of the above shown coefficients is approxi¬ mately .04 for all except the last, where it drops to less than half that amount. On the basis of the total showing made in the data it was concluded that the determination of the general intelligence of the subjects had been reliably made, and that it was safe to use the results as a criterion in the remainder of the study. The next step was to give to the same subjects a group intelli¬ gence test consisting of twenty single tests, nine of which were predominantly of the perceptual type, and eleven predominantly of the symbol type.* Before these tests could be given the number of subjects in the group had been reduced, by graduation and other factors, to 222. The raw data for the group tests of these 222 subjects is shown in Table IV. The mental ages given in the table are rectified mental ages. They have been brought up to * Copies of these tests, and also of the tests used in the lower grade investi¬ gation, are filed at Stanford University. MODERN METHODS OF MENTAL MEASUREMENT 69 date by the usual method based upon ( 1 ) the difference between the date of the Binet and the date of the other test, and (2) the theory that the I. Q. (relation of chronological and mental age) remains approximately constant. Table IV, A Raw Data for the Nine Perceptual Tests. Eighth Grade. Group A Case 123 4 5 Total 1 Group B 234 Total Total IQ CA MA 40 16 8 32 18 20 94 4 10 9 9 32 126 99 15-2 15-0 5i 15 9 30 15 8 77 7 9 9 13 38 H5 98 17-0 15-8 54 13 11 39 18 9 90 8 8 10 15 4i 131 102 14-8 14-10 56 13 11 39 18 7 88 10 5 9 15 39 127 93 15-6 14-4 59 16 11 37 18 20 102 10 10 9 10 39 141 104 14-2 14-8 60 13 7 3i 1 7 6 74 9 7 9 15 40 114 97 16-4 15-10 63 14 9 35 18 7 83 10 10 9 7 36 1 19 79 17-0 12-9 65 15 11 34 1 7 14 9i 6 9 8 11 34 125 106 14-6 15-4 66 13 8 35 18 15 89 10 7 9 12 38 127 97 13-11 13-5 7i 13 10 39 18 16 96 9 7 8 14 38 134 81 15-2 12-4 72 13 1 2 39 17 14 95 10 9 10 15 44 139 96 15-10 14-3 Seventh Grade 2 14 6 35 16 12 83 9 8 10 11 38 121 hi 14-2 15-8 3 16 13 37 18 17 IOI 9 10 10 15 44 145 121 13-9 16-7 4 15 9 30 11 16 81 10 8 6 7 31 112 93 15-8 14-7 5 15 12 39 1 7 1 7 100 10 10 10 14 44 144 116 14-7 16-10 6 15 9 32 15 18 89 9 10 9 9 37 126 93 17-2 14-10 7 14 10 29 15 9 77 10 8 10 12 40 1 17 no 14- 1 15-5 11 16 9 37 18 13 93 10 9 9 12 40 133 109 14-n 16-5 12 16 11 35 17 13 92 10 10 10 13 43 135 121 14-0 16- 1 1 13 15 12 38 18 12 95 10 10 9 14 43 138 123 13-3 16-3 14 13 11 32 11 16 83 10 9 9 12 40 123 93 16-0 15-0 1 7 15 11 38 16 16 96 10 10 10 12 42 138 141 14-0 19-9 18 12 9 3i 14 8 74 9 6 8 12 35 109 62 15-10 9-10 19 15 12 32 18 20 97 10 10 10 12 42 139 93 i5-i 14-0 21 12 12 35 15 17 9i 10 10 8 13 4i 132 89 15-4 13-7 22 15 11 37 18 14 95 10 9 8 15 42 137 no 13-n 15-4 23 16 9 26 15 13 79 8 8 9 10 35 114 99 14-5 14-3 24 15 10 28 15 11 79 9 10 9 10 38 11 7 1 19 14-3 16-n 25 15 7 27 18 16 83 9 10 9 14 42 125 118 12-11 15-2 26 14 10 36 16 18 94 9 9 9 14 4i 135 107 15-3 16-5 27 14 9 26 15 10 74 7 9 8 8 32 106 92 14-0 12-10 30 13 11 39 18 12 93 10 10 9 15 44 137 115 14-0 1 6- 1 3i 13 10 32 18 15 88 10 8 9 12 39 127 100 13-n 13-10 33 14 10 35 18 20 97 10 10 10 13 43 140 127 14-0 17-9 35 14 9 36 18 11 88 10 10 10 13 43 131 106 14-1 15-0 37 15 9 25 18 11 78 10 8 8 8 34 112 88 15-8 13-8 38 15 7 32 10 9 73 10 8 9 6 33 106 88 14-9 12-11 39 15 10 24 18 12 79 9 8 10 10 37 116 109 14-5 15-10 40 13 9 26 13 11 72 6 8 3 9 26 98 95 13-3 12-8 4i 14 7 29 16 14 80 9 9 10 13 4i 121 100 15-9 15-9 42 16 8 37 18 17 96 9 10 10 13 42 138 ii7 14-5 16-10 43 14 7 22 17 11 7 1 10 9 9 13 4i 1 12 93 14-5 13-4 45 15 12 32 18 13 90 10 10 9 11 40 130 130 13-0 16-10 46 16 9 28 18 13 84 8 10 9 12 39 123 97 14-2 13-8 70 JAMES LEROY STOCKTON Table IV, A (Continued) Group A Case 123 4 5 Total Seventh Grade Group B 1234 Total Total IQ CA MA 47 14 7 39 16 9 85 10 9 8 10 37 122 80 14-5 1 1-5 48 16 8 34 14 12 84 10 10 10 10 40 124 148 12-6 18-5 49 14 10 38 18 16 96 8 7 8 14 37 133 91 13-n 12-8 50 12 11 39 18 12 92 10 8 8 13 39 131 1 14 12-11 14-9 5i 15 8 34 1 7 13 87 9 9 10 10 38 125 74 16-1 12-1 52 14 12 35 18 14 93 10 8 10 14 42 135 114 13-8 15-7 53 15 12 37 18 1 7 99 10 5 8 12 35 134 99 14-5 14-3 54 13 10 30 16 20 89 9 8 10 10 37 126 83 14-10 12-4 55 14 7 3i 1 7 1 7 86 10 6 7 14 37 123 84 14-8 12-4 56 12 10 35 15 7 79 10 6 8 9 33 1 12 122 12-10 15-7 57 14 11 39 13 14 9i 10 7 9 14 40 131 93 14-0 13-0 58 16 12 34 18 17 97 10 10 10 14 44 141 113 13-n 15-8 60 15 9 39 15 20 98 10 10 9 15 44 142 121 13-6 16-3 61 13 9 39 18 16 95 9 10 9 10 39 133 112 14-0 15-10 62 12 9 26 18 10 75 9 9 10 10 38 11 3 93 13-6 12-6 63 9 8 25 14 13 69 10 3 7 9 29 98 88 14-10 13-0 64 14 9 3i 12 13 79 10 7 8 14 39 1 18 92 14-2 13-0 65 15 10 27 17 14 83 9 10 10 9 38 121 128 13-4 17-2 66 12 10 35 18 18 93 10 7 7 11 35 128 IIO 13-8 15-1 6 7 16 12 36 16 17 97 10 9 8 14 4i 138 1 22 ii-ii 14-5 1 14 10 39 15 2 80 Si: 5 >cth 8 G 9 rac 9 e 3i in 98 13-4 I3-I 2 15 8 20 17 14 74 6 10 9 14 39 113 81 15-5 12-6 3 12 9 37 18 16 92 9 9 8 9 35 127 99 15-7 15-4 6 14 10 33 18 15 90 10 10 8 8 36 126 102 13-5 13-8 7 11 10 28 16 12 77 9 10 6 9 34 in 85 15-4 13-0 8 16 9 3i 17 13 86 8 9 10 9 36 122 86 14-10 12-8 9 13 8 37 15 18 9i 9 10 9 14 42 133 94 13-10 13-1 10 16 10 35 18 16 95 10 10 9 14 43 138 140 12-4 17-3 12 10 7 3i 12 14 74 8 0 5 14 27 101 74 17-0 12-0 13 16 6 30 13 11 76 8 10 12 13 4i 117 101 13-3 13-5 14 16 14 39 18 20 107 9 9 9 15 42 149 94 13-n 13-2 15 11 9 35 18 16 89 10 9 10 10 39 128 88 13-10 12-3 16 15 10 37 13 14 89 10 10 9 10 39 128 107 13-8 14-7 17 16 12 39 18 17 102 9 10 10 15 44 146 98 13-n 13-9 18 14 10 39 18 11 92 10 6 6 15 37 129 9i 12-10 n-8 21 14 8 39 18 12 9i 9 9 7 13 38 129 102 12-0 12-3 22 16 11 37 18 14 96 9 10 9 8 36 132 120 13-10 16-6 23 13 8 24 16 16 77 9 10 9 9 37 114 107 13-3 14-2 24 15 12 39 17 15 98 10 10 10 13 43 141 143 11-8 16-8 25 14 10 32 17 16 89 10 9 10 13 42 131 135 12-8 17-0 26 12 9 34 18 12 85 10 7 9 9 35 120 79 15-0 II-IO 27 12 9 37 18 14 88 7 5 7 12 3i 119 72 14-3 10-4 30 16 10 35 11 17 89 10 8 10 13 41 130 105 12-10 13-5 32 12 8 30 16 10 76 8 9 8 7 32 108 98 13-9 i3-4 35 14 7 28 18 10 77 9 10 9 11 39 1 16 123 12-11 15-10 36 15 9 37 14 11 86 9 10 9 15 43 129 134 12-3 16-4 38 15 11 37 18 14 95 9 9 9 13 40 135 108 13-7 14-9 39 13 9 29 14 6 7i 10 10 4 10 34 105 9i 13-3 12-1 MODERN METHODS OF MENTAL MEASUREMENT 71 Table IV, A (Continued) Sixth Grade Group A Group B Case 1 2 3 4 5 Total 1 2 3 4 Total Total IQ CA MA 4i 15 11I39I18 11 94 9 9 9 14 4i 135 no 14-3 15-8 42 10 11 37 18 17 93 10 8 7 14 39 132 122 13-9 16-8 43 12 9 36 16 16 89 9 8 8 9 34 123 104 12-10 13-4 44 15 10 29 16 9 79 9 9 10 8 36 115 88 14- 1 1 13-2 45 15 10 32 18 10 85 10 8 10 13 4i 126 119 13-9 16-4 46 14 7 28 14 13 76 10 8 8 9 35 hi in 12-11 14-5 47- 8 8 25 15 11 67 6 8 7 9 30 97 93 13-5 12-7 49 14 10 30 15 12 81 10 9 0 9 28 109 89 13-3 II-IO 50 14 8 3i 12 15 80 9 8 8 14 39 119 87 14-5 12-6 5i 15 12 29 14 10 80 9 8 10 9 36 116 121 12-7 15-2 52 15 7 23 11 17 73 10 9 9 6 34 107 105 13-1 13-8 54 14 8 27 17 18 84 8 9 8 12 37 121 119 13-7 16-2 55 16 8 24 18 14 80 8 9 7 11 35 ii5 117 12-7 14-7 56 12 8 33 13 11 77 10 4 7 11 32 109 97 1 1-9 10-8 57 14 7 39 14 13 87 6 9 7 11 33 120 126 13-n 17-6 58 11 7 19 18 17 72 7 8 3 0 18 90 119 12-3 14-6 59 12 6 26 7 12 63 9 10 8 9 36 99 98 12-11 12-5 61 8 7 25 10 12 62 10 5 8 12 35 97 9i 13-2 ii-ii 66 13 9 39 18 14 93 10 7 10 11 38 131 100 12-1 12-1 6 7 12 9 27 14 8 70 8 9 4 12 33 103 92 13-1 12-0 70 13 9 39 17 10 88 9 8 0 8 25 113 82 14-10 12-5 7 1 15 13 30 18 18 94 8 9 10 15 42 136 109 14- 1 15-4 72 12 12 30 13 20 87 9 9 8 11 37 124 102 12-9 13-1 73 7 7 34 1 7 10 75 8 6 7 9 30 105 74 15-2 1 1-3 Fifth Grade Group A Group B Case 12345 Total 1234 Total Total IQ CA MA 1 7 8 30 11 14 70 9 9 8 11 37 107 105 II-IO 12-5 2 14 0 29 18 17 78 9 8 9 9 35 1 13 97 13-3 12-10 3 13 8 28 13 14 76 8 6 5 12 3i 107 84 13-5 1 1-4 5 9 7 22 10 16 64 9 10 8 10 37 IOI 80 13-4 10-7 6 13 9 25 12 11 70 9 8 9 11 37 107 94 13-2 12-4 7 15 7 26 14 13 75 9 9 9 9 36 in 152 ii-3 17-4 8 14 9 29 18 6 76 9 9 8 12 38 114 105 1 1-7 12-1 9 14 8 30 13 17 82 7 10 10 4 3i 11 3 127 13-1 16-6 10 11 8 3i 18 17 85 10 9 10 15 44 129 117 13-7. 15-n 11 14 7 28 8 11 68 8 7 7 6 28 96 93 13-10 12-10 15 12 7 28 11 8 66 9 5 9 8 31 87 80 i5-i 12-1 16 14 8 27 1 7 6 72 9 9 7 12 37 104 98 II-IO 1 1-8 1 7 14 6 30 14 14 78 9 9 6 11 35 113 84 13-3 1 1-2 18 14 7 27 1 7 18 83 8 8 7 11 34 117 118 12-1 14-3 19 12 8 28 14 14 76 9 10 8 4 3i 107 1 16 12-7 14-6 20 12 10 22 16 15 75 10 8 10 8 36 in no 12-6 13-9 21 15 9 27 15 18 84 9 9 9 10 37 121 86 15-3 i3-3 22 14 8 32 17 11 82 9 10 8 10 37 119 151 10-9 16-3 23 13 9 32 11 i5 80 10 9 9 9 37 117 98 12-9 12-5 24 12 7 30 15 16 80 10 9 10 13 42 121 103 1 1-9 12-1 25 14 12 39 18 14 97 10 10 9 13 42 139 95 12-2 1 1-8 26 13 9 27 11 10 70 9 9 7 5 30 100 97 12-6 1 2-2 27 13 9 3i 12 14 79 9 5 6 10 30 109 1 85 14-2 12-0 ■4 72 JAMES LEROY STOCKTON Table IV, A (Continued) Fifth Grade (Continued) Group A Case 123 4 5 Total 1 Group B 234 Total Total IQ CA MA 29 12 10 27 12 18 79 10 7 1 13 3i no 94 12-1 1 1-5 30 13 8 25 14 15 75 10 9 9 12 40 115 113 12-1 13-7 3i 1 2 9 21 9 11 62 5 9 10 8 32 94 88 14-3 12-6 32 13 9 24 9 12 67 7 10 6 11 34 IOI 113 1 1-4 12-10 33 14 7 33 15 7 76 9 5 5 8 27 103 100 1 1-6 11-7 35 14 8 28 16 15 81 8 9 10 i5 42 123 194 12-5 12-11 36 15 8 25 12 9 69 9 6 7 7 29 98 90 12-10 1 1-7 38 1 2 10 34 11 11 78 9 10 7 9 35 11 3 9i 12-4 1 1-3 39 14 9 22 1 3 10 68 8 9 5 9 3i 99 108 12-6 13-6 40 13 9 39 17 13 9i 10 8 7 8 33 124 106 ii-5 12-1 4i 9 8 24 15 14 70 10 8 10 8 36 106 126 11-7 14-6 44 14 9 20 11 16 70 9 7 9 9 34 104 116 11-2 12-11 45 14 9 28 15 12 78 9 9 8 7 33 in 105 12-2 12-8 a6 14 7 26 15 14 76 10 9 10 9 38 1 14 143 10-8 15-3 47 9 9 26 18 14 76 10 7 8 8 33 109 in ii-5 12-8 5i 14 9 22 18 0 63 8 8 8 0 24 87 76 13-8 10-5 52 15 7 27 10 11 70 8 9 7 8 32 102 89 13-5 ii-ii 53 12 7 39 13 13 84 9 10 0 8 27 in 93 13-9 II-IO 54 13 7 20 11 9 60 10 10 7 8 35 95 136 11-6 15-8 55 13 9 26 10 1 59 9 8 7 11 35 94 82 12-7 10-4 56 14 8 27 10 11 60 8 5 6 9 28 88 109 1 1-8 12-8 57 12 8 27 14 17 78 8 8 8 9 33 in 85 13-n 1 1-9 58 13 7 25 12 14 7i 9 9 6 6 30 IOI 106 10-8 ii-3 59 15 8 28 16 20 87 9 10 8 12 39 126 84 13-2 1 1-2 61 16 8 26 14 13 77 8 8 9 10 35 112 88 1 1-9 10-3 62 10 8 23 9 12 62 5 10 7 9 3i 93 93 1 1-4 10-6 63 13 6 25 15 11 70 6 10 8 14 38 108 95 10-9 10-3 64 14 9 23 9 15 70 7 10 8 8 33 103 98 1 1-8 ii-5 65 11 7 25 11 0 54 10 6 7 8 3i 85 9i 1 1-2 IO-I 67 15 9 32 15 11 82 7 8 8 15 38 120 95 11-6 II-O 68 13 10 37 15 12 87 5 7 8 10 30 117 93 II-IO II-O 69 15 6 37 14 12 84 6 7 8 15 36 120 75 13-6 IO-I 70 9 7 3i 14 0 61 8 8 10 9 35 96 94 ii-ii 1 1-2 7 1 14 9 21 12 5 61 10 10 8 11 39 100 162 1 1-2 l8-0 74 10 8 26 11 4 49 9 8 8 12 37 86 83 12-2 IO-I 75 14 9 36 15 9 83 7 8 8 13 36 119 100 1 1-9 1 1-9 78 14 8 27 18 17 84 8 8 9 13 38 122 95 11-9 11-2 79 13 7 35 13 7 75 9 8 8 11 36 hi 89 12-7 1 1-2 Fourth Grade I 14 6 21 10 13 64 5 8 9 10 32 96 108 ii-3 12-2 2 15 7 23 5 0 50 8 7 6 8 29 79 88 ii-i 9-9 5 11 7 26 10 14 68 8 10 8 6 32 100 126 1 1-3 14-0 6 13 8 25 13 11 70 9 10 4 13 36 106 103 1 1-4 1 1-8 9 11 8 25 16 14 74 8 6 10 13 37 in 126 .10-8 13-4 10 14 7 22 11 18 72 10 9 9 10 38 no 99 ii-ii 1 1-9 11 13 9 28 18 16 84 9 10 9 8 36 120 88 1 1-9 10-4 13 i5 11 29 18 16 89 10 10 10 13 43 132 141 12-0 16-10 14 13 9 25 10 12 69 8 10 9 8 35 104 108 12-7 13-8 15 13 8 21 14 11 67 9 9 6 12 3d 103 102 ii-5 11 -7 17 12 8 3i 16 12 79 7 6 9 8 30 109 89 II-O 9-9 18 13 11 3i 13 1 7 85 8 10 10 13 4i 126 148 9-9 14-4 19 13 9 32 13 14 81 6 9 8 11 34 1 15 100 10-7 IO-I 1 MODERN METHODS OF MENTAL MEASUREMENT 73 Table IV, A (Continued Fourth Grade (Continued) Group A Group B Case 1 2 3 4 5 Total 1 2 3 4 Total Total IQ CA MA 20 13 8|2i 15 14 7 1 8 8 5 14 35 106 90 12-10 1 1-6 21 9 8 21 9 4 5i 8 8 3 6 25 76 93 ii-7 10-9 22 13 5 28 10 11 67 9 7 7 10 33 100 79 12-7 10-0 23 15 8 25 13 13 74 7 10 8 7 32 106 138 11-0 15-6 25 10 7 19 4 13 53 8 7 0 8 23 76 69 12-11 8-11 27 16 4 17 12 8 57 4 5 2 5 16 73 70 13-0 9-3 28 11 8 25 10 7 61 8 4 1 12 25 86 73 12-3 9-0 29 13 5 23 12 3 56 9 4 2 10 25 81 73 12-3 9-0 30 14 7 30 14 1 7 82 9 7 8 11 35 11 7 114 ii-3 12-9 31 15 7 19 15 12 68 4 7 10 9 30 98 92 II-IO 10-10 32 12 6 18 12 7 55 10 10 8 12 40 95 9i 1 1-7 10-6 33 12 9 30 1 7 13 81 8 6 8 8 30 hi 121 10-6 12-8 35 13 7 25 10 12 67 8 8 8 6 30 97 77 13-5 10-4 38 14 8 24 17 13 76 6 8 9 8 3i 107 1 12 10-2 ii-5 40 14 7 25 18 14 78 6 9 8 12 35 1 13 1 19 10-4 12-4 46 10 5 18 0 4 37 10 6 6 6 28 65 1 16 9-7 11-1 47 9 9 25 12 12 67 9 9 8 7 33 100 112 10- 1 1 1-4 48 12 2 23 7 0 44 6 6 2 6 20 64 92 1 1 -5 10-6 49 14 7 24 9 12 66 9 8 4 6 27 93 96 1 1-2 10-9 51 11 7 24 9 11 62 9 7 9 13 38 100 112 10-4 ii-7 52 11 8 27 15 11 72 8 7 7 13 35 107 98 1 1“5 ii-3 54 12 7 26 11 13 69 8 9 7 6 30 99 138 9-11 13-8 5^ 10 7 28 12 13 70 8 7 9 10 34 104 107 10-8 1 1-5 57 15 7 37 13 7 74 9 9 7 7 32 hi 1 16 10-0 1 1-6 58 12 6 19 13 13 63 6 8 7 5 26 89 94 10-9 10- 1 59 15 10 21 15 11 72 10 9 8 7 34 106 100 II-O 11-0 60 10 7 27 9 11 64 9 8 6 4 27 9i 114 9-7 10- 1 1 61 11 7 28 13 11 70 9 8 5 11 33 103 90 10-5 9-4 62 8 6 22 8 3 47 7 4 6 3 20 67 82 14- 1 11-6 64 11 7 21 13 14 66 9 9 8 6 32 98 9i 1 1-9 10-8 65 12 9 29 14 14 78 9 9 9 13 40 1 18 82 12- 1 1 0-0 66 9 7 19 8 12 55 8 0 6| 7 21 76 103 10-2 10-5 Table IV, B Raw Data for the Eleven Symbol Tests. Eighth Grade Group A Group B Case 1 2 3 4 5 6 Total I 2 3 4 5 Total Total IQ CA MA 40 8 7 23 25 9 22 94 14 3i 10 10 22 87 181 99 15-2 15-0 5i 7 6 33 28 10 11 95 11 32 9 17 18 87 182 98 17-0 15-10 54 7 7 27 28 14 21 104 14 30 9 13 21 87 191 102 14-8 14-10 56 7 7 16 22 10 18 80 14 16 7 11 18 66 146 93 15-6 14-4 59 11 8 19 3i 13 21 103 15 32 9 15 20 91 194 104 14-2 14-8 60 5 7 14 25 9 14 74 10 22 9 10 15 66 140 97 16-4 15-10 63 6 7 14 21 9 11 68 10 27 9 7 11 64 132 79 17-0 12-9 65 6 9 34 35 15 22 121 10 33 9 19 21 92 213 106 14-6 15-4 66 5 5 16 20 9 15 70 12 22 8 10 12 64 134 97 13-n 13-5 7i 8 9 19 23 9 14 82 14 32 10 13 16 85 167 81 15-2 12-4 72 4 8 22 26 15 17 92 12 28 8 15 23 86 178 9 6 15-10 14-3 74 JAMES LEROY STOCKTON Table IV, B (Continued) Seventh Grade Group A Group B Case 1 2 3 4 5 6 Total I 2 3 2 9 8 20 26 13 15 9i 14 25 8 3 10 9 33 24 16 22 114 14 30 10 4 6 6 21 28 8 14 83 10 25 8 5 13 9 30 38 13 23 126 14 36 10 6 10 7 24 27 10 20 98 13 25 9 7 9 7 19 25 10 22 92 12 24 9 ii 5 8 14 29 8 19 83 10 20 9 12 10 7 25 3i 11 20 104 14 36 10 13 7 7 27 38 15 22 1 16 15 33 10 14 6 8 1 7 24 9 18 82 15 29 9 1 7 10 8 23 35 14 23 113 12 34 10 18 3 5 9 10 6 9 42 10 1 7 •5 19 8 8 24 30 13 19 102 13 34 9 21 5 7 17 13 11 15 68 11 25 9 22 6 7 19 26 11 23 92 14 3i 10 23 9 8 27 26 11 20 IOI 13 26 10 24 8 8 1 7 27 11 14 85 10 28 10 25 10 6 23 30 6 19 94 14 29 9 26 10 9 23 21 9 21 93 1 1 18 7 27 8 9 22 28 6 19 92 10 19 6 30 11 9 22 3i 14 21 108 16 32 8 31 2 8 24 33 11 18 96 15 25 9 33 7 8 19 35 9 23 IOI 15 33 10 35 5 8 12 26 5 17 73 11 15 7 37 5 6 15 22 8 17 73 13 21 9 38 7 6 25 24 9 14 85 9 28 8 39 8 7 21 27 9 22 94 11 21 8 40 6 8 18 27 10 17 86 9 25 8 4i 6 8 24 26 10 19 93 11 19 8 42 7 6 29 25 13 15 95 13 28 9 43 6 8 21 24 9 22 90 11 27 7 45 8 8 24 29 11 21 IOI 13 34 9 46 8 7 15 18 10 14 72 11 12 6 47 6 6 14 19 9 15 69 13 23 9 48 10 9 32 34 15 21 121 16 39 10 49 5 8 21 22 10 17 83 13 33 9 50 9 9 28 3i 13 22 112 14 36 10 5i 5 7 21 25 9 14 81 10 24 6 52 10 8 22 27 11 21 99 12 22 10 53 7 8 15 23 7 17 77 13 1 7 8 54 3 7 11 12 6 11 50 7 21 7 55 7 7 23 26 13 13 89 12 24 9 56 6 7 1 7 24 10 15 79 12 20 8 57 7 8 1 7 28 12 18 90 10 27 9 58 8 8 26 27 12 22 103 11 32 9 60 8 7 25 3i 10 20 IOI 12 36 8 61 3 8 16 24 11 1 7 79 11 30 10 62 6 7 24 27 9 15 88 12 28 9 63 6 7 19 25 10 17 84 12 25 8 64 4 8 13 16 10 16 67 9 20 10 65 9 6 27 38 13 21 1 14 12 34 10 66 6 8 18 25 14 19 90 15 20 9 67 5 8 25 26 14 21 99 9 29 10 4 5 Total Total IQ CA MA 14 18 79 170 in 14-2 15-8 10 21 85 199 121 13-9 16-7 10 1 7 70 153 93 15-n 14-7 14 22 96 222 116 14-7 16-10 11 15 73 171 93 17-2 14-10 9 21 75 167 no 14-1 15-5 11 18 68 151 109 14-n 16-5 13 21 94 198 121 14-0 16-n 15 23 96 212 123 13-3 16-3 13 1 7 83 165 93 16-0 15-0 1 7 16 89 202 141 14-0 19-9 8 9 49 9i 62 15-10 9-10 14 18 88 190 93 15-1 14-0 13 14 72 140 89 15-4 13-7 12 18 85 1 77 no 13-n 15-4 • 9 19 77 178 99 14-5 14-3 13 18 79 164 119 14-3 16- 1 1 8 11 7 1 165 118 12-11 15-2 13 19 68 161 107 15-3 16-5 10 1 7 62 154 92 14-0 12-10 13 20 89 197 ii5 14-0 16-1 12 15 76 172 100 13-n 13-10 13 18 89 190 127 14-0 17-9 6 9 48 121 106 14- 1 15-0 13 18 74 147 88 15-8 13-8 13 11 69 154 88 14-9 12-11 14 18 72 1 66 109 14-5 15-10 9 17 68 154 95 13-3 12-8 7 20 65 158 100 15-9 15-9 13 22 85 180 n 7 14-5 16-10 7 19 7i 161 93 14-5 13-4 10 18 84 185 130 13-3 16-10 10 21 60 132 97 14-2 13-8 11 15 7 1 140 80 14-5 ii-5 12 22 99 220 148 12-6 18-5 11 20 86 169 9i 13-n 12-8 14 22 96 208 114 12-11 14-9 12 13 65 146 74 16-1 12-1 12 15 7 1 170 114 13-8 15-7 9 1 7 64 141 99 i4-5 14-3 10 15 60 no 83 14-10 12-4 13 18 76 165 84 14-8 12-4 15 16 7i 150 122 12-10 15-7 17 14 77 167 93 14-0 13-0 14 22 88 191 11 3 13-n 15-8 8 21 85 186 121 13-6 16-3 15 16 82 161 112 14-0 15-10 6 22 77 165 93 13-6 12-6 9 14 68 152 88 14-10 13-0 12 21 72 139 92 14-2 13-0 21 14 9i 205 128 13-4 17-2 13 19 76 166 no 13-8 1 5- 1 15 20 83 182 | 122I 11-11I14-5 MODERN METHODS OF MENTAL MEASUREMENT Table IV, B (Continued) Sixth Grade Group A Group B Case 1 2 3 4 5 6 Total 1 2 3 4 5 Total Total IQ CA 1 6 7 1 7 20 7 17 74 9,27 7 9 16 68 142 98 13-4 2 3 7 15 22 8 13 68 8 23 6 9 19 65 133 81 15-5 3 8 4 22 25 11 15 85 12 27 9 8 19 75 160 99 15-7 6 8 8 16 32 11 20 95 13 34 10 10 19 86 181 102 13-5 7 4 3 7 18 5 12 49 9 19 8 7 12 55 104 85 15-4 8 5 7 17 21 11 19 80 12 21 9 5 12 59 139 86 14-10 9 6 8 15 16 8 16 69 10 25 5 6 18 64 133 94 13-10 10 9 8 25 34 14 12 102 11 34 10 14 20 89 191 140 12-4 12 1 6 17 22 10 1 7 73 11 16 7 7 15 56 129 74 17-0 13 3 7 18 15 10 21 74 13 19 9 11 18 70 144 101 13-3 14 6 9 15 15 11 12 68 12 19 9 12 15 67 135 94 13-n 15 4 7 20 24 9 11 75 12 3i 9 13 19 84 159 88 13-10 16 7 9 26 38 13 18 hi 11 3i 7 8 19 76 187 107 13-8 1 7 5 7 22 21 11 18 84 12 19 10 13 19 73 157 98 13-n 18 4 8 16 24 12 13 77 14 27 6 14 18 79 156 91 12-10 21 6 6 12 27 10 16 77 10 18 9 9 16 62 139 102 12-0 22 8 9 22 32 14 18 103 11 28 10 10 16 75 178 120 13-10 23 7 6 12 22 10 15 72 10 23 8 8 16 65 137 107 13-3 24 8 9 24 30 13 21 105 11 36 10 13 22 92 197 143 1 1-8 25 9 8 14 27 11 18 87 14 28 10 11 17 78 165 135 12-8 26 8 6 9 14 8 14 59 12 23 6 9 11 61 120 79 15-0 27 3 7 16 19 8 13 66 12 20 8 10 17 67 133 72 14-3 30 5 9 24 25 10 9 82 10 33 7 15 19 84 166 105 12-10 32 5 7 14 23 10 12 7i 11 28 7 10 19 75 146 98 13-9 35 10 9 20 27 9 20 95 11 26 10 10 18 75 170 123 12-11 36 8 7 28 22 14 19 98 10 34 9 15 22 90 188 134 12-3 38 8 8 23 24 7 19 89 11 26 10 14 18 79 168 108 13-7 39 4 8 26 25 12 15 90 10 26 9 13 21 79 169 9i 13-3 4i 5 8 24 38 13 17 105 14 30 9 18 22 93 198 no 14-3 42 6 7 20 20 13 18 84 10 29 8 13 20 80 164 122 13-9 43 7 7 15 21 10 16 76 10 26 10 10 17 73 149 104 12-10 44 8 5 10 28 8 16 75 11 23 5 9 16 64 139 88 14-n 45 9 7 18 28 9 1 7 88 12 27 9 14 22 84 172 119 13-9 46 8 8 16 28 10 12 82 13 28 8 11 15 75 157 in 12-11 47 4 7 11 21 8 15 66 9 20 9 7 12 57 123 93 13-5 49 8 7 15 26 10 17 83 12 24 7 12 15 7o 153 89 13-3 50 5 7 19 17 10 15 73 12 30 9 10 15 76 149 87 14-5 5i 9 8 19 30 10 22 98 11 34 10 5 18 78 176 121 12-7 52 5 7 10 21 5 10 58 11 20 9 8 12 60 1 18 105 13-1 54 7 7 21 27 11 22 95 10 35 9 9 16 79 174 119 13-7 55 6 6 9 18 9 13 61 10 19 8 10 15 62 123 117 12-7 56 5 7 1 7 22 8 8 67 11 22 6 11 17 67 134 97 1 1-9 57 9 8 18 3i 12 21 99 11 23 10 13 23 80 179 126 13-n 58 9 5 25 23 10 17 89 11 30 7 10 11 69 158 119 12-3 59 6 5 8 18 4 14 55 10 17 7 9 12 55 no 96 12-11 61 6 6 12 25 10 1 7 76 8 20 10 12 16 66 142 9i 13-2 66 4 6 13 24 11 22 80 10 23 6 13 17 69 149 100 12-1 67 5 5 8 19 7 11 55 8 1 7 6 7, 8 46 101 92 13-1 70 4 7 10 0 11 10 42 11 20 5 9U3 58 100 82 14-10 7 1 6 9 1 7 18 11 21 82 11 22 9 9I21 72 154 109 14- 1 72 4 6 14 12 9 17 62 10 22 7 61 17 62 124 102 12-9 73 2 5 13 19 8 11 58 11 261 6| n| 12 66 124 74 15-2 MA i3-i 12- 6 15- 4 13- 8 13-0 12- 8 13- 1 17-3 12- 0 13- 5 13- 2 12- 3 14- 7 13- 9 1 1- 8 12- 3 16- 6 14- 2 16- 8 17- 0 11- IO 10- 4 13- 5 13- 4 15- 10 16- 4 14- 9 12- 1 15- 8 16- 8 13- 4 13- 2 16-4 14- 5 12- 7 11- IO 12- 6 15- 2 13- 8 16- 2 14- 7 10- 8 17- 6 14- 6 12-5 11- ii 12- 1 12-0 12- 5 15- 4 13- 1 1 1-3 76 JAMES LEROY STOCKTON Table IV, B (Continued) Fifth Grade Group A Group B Case 1 2 3 4 5 6 Total 1 2 3 4 5 Total Total IQ CA MA i 6 8 13 20 8 16 7i 11 22 7 12 3 55 126 105 ii-io 12-5 2 7 6 14 22 9 10 68 11 27 6 8 15 67 135 97 13-3 12-10 3 3 3 11 20 5 8 50 5 19 5 8 12 49 99 84 13-5 1 1-4 5 6 6 14 20 8 10 64 9 21 6 9 10 55 119 80 13-4 10-7 6 7 8 13 20 7 15 70 10 19 9 10 12 60 130 94 13-2 12-4 7 11 7 20 28 14 22 102 10 3i 10 9 12 72 174 152 ii-3 17-4 8 7 7 18 22 10 17 81 10 18 7 9 18 62 '143 105 n -7 12-1 9 7 7 20 3i 12 M 9i 6 26 8 16 19 75 166 127 13-1 16-6 io 7 9 25 3i 13 21 106 10 39 8 1 1 22 90 196 117 13-7 i5-n ii 4 4 6 16 7 1 1 48 9 18 7 9 12 55 103 93 13-10 12-10 15 1 8 5 12 14 9 5 53 9 16 3 7 12 47 100 80 15-1 12-1 16 5 6 12 22 8 15 68 12 21 8 11 13 65 133 98 11-10 1 1-8 1 7 5 6 13 17 9 12 62 8 23 7 13 17 68 130 84 13-3 1 1-2 18 3 7 16 23 8 12 69 12 25 7 11 19 74 M3 118 12-1 14-3 19 12 8 21 28 11 21 101 12 32 10 15 21 90 191 116 12-7 14-6 20 8 7 18 27 11 22 93 9 33 9 15 20 86 179 no 12-6 13-9 21 4 8 16 22 10 11 7i 8 26 9 10 16 69 140 86 15-3 13-3 22 7 7 24 38 10 19 105 12 34 10 16 17 89 194 151 10-9 16-3 23 4 8 16 17 10 15 70 10 22 8 9 15 64 134 98 12-9 12-5 24 7 7 14 25 11 14 78 11 23 9 10 15 68 146 103 1 1-9 12-1 25 8 8 15 24 9 20 84 9 27 9 9 14 68 152 95 12-2 1 1-8 26 4 7 9 14 9 9 52 10 18 5 9 13 55 107 97 12-6 12-2 27 3 7 13 21 10 15 69 9 18 5 9 11 52 121 85 14-2 12-0 29 5 7 18 15 7 12 64 9 16 8 6 9 48 1 12 94 12-1 ii-5 30 7 8 24 30 10 20 99 11 28 9 13 12 73 172 11 3 12-1 13-7 31 6 2 15 6 5 14 48 10 17 5 8 8 48 96 88 14-3 12-6 32 7 7 25 27 12 18 96 12 25 10 8 18 73 169 113 11-4 12-10 33 4 7 9 19 8 12 59 10 17 9 7 12 55 114 100 1 1-6 1 1-7 35 5 6 18 26 11 18 86 12 24 7 11 16 70 156 104 12-5 12-11 36 3 6 14 25 9 12 69 9 25 7 13 15 69 138 90 12-10 ii-7 38 7 7 12 14 9 10 59 11 23 6 9 11 60 119 91 12-4 ii-3 39 5 4 11 16 8 12 56 8 27 7 9 16 67 123 108 12-6 13-6 40 7 7 13 21 8 17 73 10 25 8 12 15 70 143 106 ii-5 12-1 4i 8 6 12 25 10 21 82 7 29 9 8 15 68 150 126 n -7 14-6 44 4 7 10 17 8 17 63 7 18 7 10 16 58 121 116 1 1-2 12- 1 1 45 4 7 13 24 7 18 73 8 23 8 11 17 6 7 140 105 12-2 12-8 46 6 8 14 23 12 18 81 12 26 8 13 16 75 156 143 10-8 15-3 47 4 7 18 27 9 15 80 9 22 10 8 14 63 143 in ii-5 12-8 5i 7 6 10 18 3 6 50 8 14 3 9 12 46 96 76 13-8 10-5 52 5 5 17 20 9 2 58 9 19 6 6 12 52 no 89 13-5 n-n 53 8 3 4 15 9 13 52 8 19 4 8 9 48 100 93 12-9 II-IO 54 9 6 20 23 11 19 88 11 24 9 11 19 74 162 136 1 1-6 15-8 55 4 6 14 14 8 6 52 7 17 5 11 18 58 no 82 12-7 10-4 56 8 5 21 14 7 13 68 12 25 5 7 18 67 135 109 1 1 -8 12-8 57 6 5 3 11 5 8 38 6 18 4 8 11 47 85 85 13-n ii-9 58 6 6 15 26 9 15 77 . 11 27 8 8 16 70 147 106 10-8 n-3 59 3 4 5 7 4 5 28 8 14 3 3 9 37 65 84 13-2 11-2 61 4 5 11 13 6 13 52 9 16 5 7 12 49 101 88 1 1-9 10-4 62 3 5 10 13 6 10 47 1 13 3 8 13 38 85 93 11-4 10-6 63 4 6 15 11 8 14 58 8 18 1 11 13 51 109 95 10-9 10-3 64 6 4 14 21 9 17 7i 6 19 6 11 18 60 131 98 1 1-8 ii-5 65 3 4 5 13 5 4 35 4 14 5 8 9 40 74 9i 1 1-2 IO-I 67 4I 6 15 0 6 14 45 10 11 4 0 17 42 87 95 n-6 n-o 68 5 7 10 14 / i| 44 10 10 6 11 15 52 96 93 II-IO n-o 69 5 5 12 10 8 13 53 6 17 6 10 13 52 105 75T3-6 IO-I MODERN METHODS OF MENTAL MEASUREMENT 77 Table IV, B (Continued) Fifth Grade (Continued) Group A Group B Case I 2 3 4 5 6 Total 1 2 3 4 5 Total Total IQ CA MA 70 5 5 10 5 6 9 40 8 14 5 8 12 47 87 94 ii-n 1 1-2 7 1 6 6 26 29 9 20 96 9 29 9 10 14 7i 167 162 11-2 18-0 74 6 3 8 9 5 13 44 9 1 7 5 8 12 5i 95 83 12-2 IO-I 75 4 5 10 16 5 13 53 11 13 4 6 9 43 96 100 1 1-9 1 1-9 78 3 3 5 4 3 5 23 8 14 2 4 11 39 62 95 1 1-9 11-2 79 2 4 3 17 11 16 53 9 14 5 6 1 7 5i 104 89 12-7 1 1-2 Fourth Grade 1 5 4 2 14 4 8 37 10 18 4 6 9 47 84 108 11 -3 12-1 2 6 5 9 18 6 5 49 5 20 4 8 11 48 97 88 ii-i 9-10 5 5 8 10 18 6 8 55 9 30 10 10 15 74 129 126 1 1-3 13-n 6 4 4 10 20 5 13 56 8 18 4 6 11 47 103 103 1 1-4 1 1-8 9 4 7 15 19 8 15 68 8 19 7 10 16 60 128 126 10-8 13-3 10 4 5 11 14 8 11 53 7 20 5 12 1 7 61 114 99 ii-n 1 1-9 11 2 4 9 10 2 14 4i 5 15 4 8 14 46 87 88 1 1-9 10-5 13 8 8 21 29 9 19 94 8 24 7 15 22 76 170 141 12-0 16-8 14 4 5 10 27 9 12 67 9 18 8 10 14 59 126 108 12-7 13-7 15 5 5 10 1 7 7 14 58 6 20 6 8 1 7 57 ii5 102 1 1 *5 1 1-7 1 7 6 6 8 19 7 15 61 9 21 9 8 15 62 123 89 II-O 9-10 18 7 8 25 30 13 21 104 10 28 10 7 19 74 178 148 9-9 14-1 19 6 7 16 18 9 13 69 9 21 10 11 18 69 138 | 100 10-7 10-7 20 6 4 9 19 6 14 58 9 13 4 8 14 48 106 90 12-10 1 1-7 21 6 4 4 19 4 13 50 8 17 6 9 10 50 100 93 1 1-7 10-10 22 4 6 9 4 6 4 33 7 16 3 9 18 53 86 79 12-7 IO-I 23 5 6 17 22 7 16 73 8 30 9 10 16 73 146 138 II-O 15-4 25 4 3 10 19 4 1 4i 5 6 3 11 13 38 79 69 12-11 9-i 27 3 6 8 17 8 9 51 5 16 5 8 10 44 95 70 13-0 9-5 28 0 2 12 10 7 6 37 7 16 4 7 9 43 80 73 12-3 9-2 29 0 2 3 0 2 5 12 7 13 2 2 4 28 40 73 12-3 9-2 30 5 5 8 13 5 10 46 8 16 4 7 12 47 93 1 14 H-3 12-8 3i 4 6 11 13 7 14 55 8 16 3 8 9 44 99 92 II-IO IO-I I 32 4 5 9 13 6 14 5i 8 20 5 5 10 48 99 9i 1 1-7 10-7 33 6 5 11 1 7 6 13 58 9 14 5 10 14 52 no 121 10-6 12-7 35 3 6 6 17 6 i5 53 8 16 7 6 12 49 102 77 13-5 10-6 38 2 8 15 18 9 11 63 8 23 7 14 20 72 135 112 10-2 1 1-4 40 7 7 17 15 11 12 69 9 18 8 15 13 63 132 119 10-4 12-2 46 6 3 7 14 6 5 4i 8 18 4 5 10 45 86 1 16 9-7 II-O 47 4 7 8 21 8 10 58 8 22 7 8 16 61 119 112 10-1 ii-3 48 3 5 13 11 7 8 47 6 15 5 7 12 45 92 92 ii-5 10-7 49 4 5 13 16 6 11 55 8 19 5 8 14 54 109 96 1 1-2 10-9 5i 2 5 5 12 3 8 35 8 19 1 1 9 38 73 112 10-4 1 1-6 52 6 5 12 14 8 4 49 0 16 7 11 15 49 98 98 1 1-5 1 1-3 54 1 7 18 25 12 19 82 9 24 9 11 18 7 1 153 139 9-1 1 13-6 55 4 3 6 14 4 9 40 7 19 3 5 10 44 84 107 10-8 1 1-4 57 6 8 16 29 9 16 84 11 24 8 8 12 63 147 1 16 10-0 ii-5 58 3 4 8 12 6 13 46 6 18 3 6 11 44 90 94 10-9 10-2 59 4 5 10 17 6 16 58 9 19 6 10 13 57 115 100 II-O II-O 60 3 6 12 23 6 11 61 7 22 7 7 16 59 120 114 9-7 10-10 61 4 4 10 8 3 8 37 7 1 7 2 8 5 39 76 90 10-5 9-5 62 2 4 4 11 5 10 36 8 14 5 3 8 38 74 82 14-1 1 1-8 64 1 2 4 6 1 5 11 29 9 1 7 2 8 9 45 74 9i 1 1-9 10-9 65 1 4 5 3 19 10 10 5i 7 17 5 7 12 48 99 82 12-1 10-2 66 1 1 3 7 16 5 10 42 8 16 5 6 9 44 86 103 10-2 10-5 78 JAMES LEROY STOCKTON The first evidence drawn from these data in favor of the theory of levels in intentionally controlled intelligence was found in cer¬ tain correlations made between the results of the individual and the combined group tests with Binet mental age. A table of these correlations is given below. Table V Correlation Coefficients of the Individual and Combined Group Tests with Binet Mental Age. I. Perceptual Tests. II. Symbol Tests. I. Picture Completion . . . 42 I. Arithmetical Reasoning.. •63 II. Series Completion . . . 46 II. Written Directions . .58 III. Comparison . . 40 III. Information . .68 IV. Symbol Digit . . 45 IV. Synonym-Antonym . •65 V. Form Combination . . . 34 V. Practical Judgment . •65 VI. Copying Designs . . . . . 30 VI. Analogies . .68 VII. Pictorial Sequence . . . 43 VII. Arithmetical Fundamen- tals . •59 VIII Pictorial Identities . 46 VIII. Vocabulary . •75 IX. Recognitive Memory . 29 IX. Sentence Completion _ .68 X. Mixed up Sentences . •53 XI. Logical Selection . .60 Total Perceptual .... Total Symbol . .80 The tests featured in the foregoing table are those used by the National Research Council in their preliminary trials for the standardization of an elementary school group test. The writer is fully aware that it is psychologically impossible to make an absolute classification of tests as “perceptual” tests and “symbol” tests. Each test is of both types to a certain degree. But it is possible to classify the tests as predominantly of one type or the other, which is all that is necessary to bring out the point in question. Assuming that this is so, the results given in the table show a decided tendency in favor of the theory being tested. The tests in which perceptual elements predominate do not cor¬ relate as highly in any case with Binet mental age as do the tests in which symbol elements predominate. The perceptual tests as a battery correlate only .60, while the symbol tests as a battery correlate .80. The majority of the individual symbol tests taken singly correlate higher with Binet mental age than does the whole bat¬ tery of perceptual tests. The vocabulary test alone, perhaps the most abstract of all, shows a coefficient which is 15 points above MODERN METHODS OF MENTAL MEASUREMENT 79 the whole perceptual battery. These differences cannot reason¬ ably be ascribed to mere differences in the amount of standardi¬ zation which the given tests have had. They have had at least approximately equal standardization. Nor can the differences reasonably be ascribed to differences in reliability of the individ¬ ual tests, although if time and other conditions had permitted the computation of reliability coefficients would have been a valuable addition to the evidence. The differences shown in the table are, however, so large that it seems a reasonable assumption that they are due, at least in part, to the fact that the two types of tests tap different levels of intelligence, and that on one of these levels, the perceptual, high and low intelligence are closer together in achievement than on the other, and therefore are not so well dif¬ ferentiated by tests which tap only that level. The next step was that of making a more definite contrast be¬ tween the achievement of high and low intelligence in the per¬ ceptual tests and in the symbol tests. The cases were first dis¬ tributed as to chronological age and I. 0. as shown in Table VI. After the cases had been distributed as to chronological age and I. Q., as shown in Table VI, a contrast was made as shown in Table VII. Middle I. Q.’s — those between 92 and 107 inclu¬ sive — were dropped; and the achievement of I. Q. below 92 was contrasted with the achievement of I. Q. above 107. The limits of the central group (a span of 15 points from 92 to 107) were chosen rather arbitrarily (1) because seven groups arranged in intervals of 15 points of I. Q. fit very well with the seven point scale upon which teachers’ judgments of intelligence were made, and (2) because by actual attempts at distribution, groups based upon intervals of 20 points proved to be too wide, while those based upon intervals of 10 points were too narrow. The contrast was made separately for the perceptual tests as a group, and for the symbol tests as another group. That is, the total scores of the low I. Q.’s in the perceptual tests were ranked and the median score found. The same was done for the scores of the high I. Q.’s in the same tests. Then the median score for low I. Q. was divided by the median score for high I. 0. Thus there was developed a ratio (or index) of the relative success of 8o JAMES LEROY STOCKTON Table VI Chronological Age and Binet I. Q. 10 No. Yrs. j I.Q. 11 No. Yrs. I.Q. 12 No. Yrs. I.Q. No. 13 Yrs. 1 I.Q. Fourth Grade Fourth Grade Fourth Grade Fourth Grade 9 10-8 126 1 11 -3 108 13 12-0 141 27 13-0 70 19 10-7 100 2 ii-i 88 14 12-7 108 35 13-5 77 33 10-6 121 5 ii-3 126 20 12-10 90 38 10-2 112 6 1 1-4 103 22 12-7 79 Fifth Grade 40 10-4 119 10 ii-ii 99 25 12-11 69 2 13-3 97 47 10- 1 1 12 11 11-9 88 28 12-3 73 3 13-5 84 5i 10-4 112 15 n-5 102 29 12-3 73 5 13-4 80 55 10-8 107 1 7 11-0 89 65 12-1 82 6 13-2 94 57 10-0 1 16 21 1 1-7 93 9 13-1 127 58 10-9 94 23 II-O 138 fifth Grade 10 13-7 117 61 10-5 90 30 1 1-3 1 14 18 12-1 118 11 13-10 93 66 10-2 103 3i II-IO 92 19 12-7 116 17 13-3 84 32 11-7 9i 20 12-6 no 5i 13-8 76 fifth Grade 48 1 1-5 92 23 12-9 98 52 13-5 89 22 10-9 151 49 1 1-2 96 25 1 2-2 95 57 13-n 85 46 10-8 143 52 ii-5 98 26 12-6 97 59 13-2 84 63 10-9 95 59 n-o 100 29 12-1 94 69 13-6 75 64 11-9 9i 30 12-1 113 35 12-5 104 Sixth Grade fifth Grade 36 12-10 90 I 13-4 98 1 II-IO 105 38 12-4 9i 6 13-5 102 7 1 1 -3 152 39 12-6 108 9 13-10 94 8 1 1-7 105 45 12-2 105 13 13-3 IOI 16 II-IO 98 53 12-9 93 14 13-n 94 24 1 1-9 103 55 12-7 82 15 13-10 88 32 1 1-4 113 74 12-2 83 16 13-8 107 33 11-6 100 79 1 2-7 89 17 13-n 98 40 ii"5 106 22 13-10 120 4i 1 1-7 126 Sixth Grade 23 1 3-3 107 44 1 1-2 1 16 10 12-4 140 32 13-9 98 47 1 1-5 hi 18 12-10 9i 38 13-7 108 54 1 1 -6 136 21 12-0 102 39 13-3 9i 56 11-8 109 25 12-8 135 42 13-9 122 61 1 1-9 88 30 12-10 105 45 13-9 H9 62 11-4 93 35 12-11 123 47 13-5 93 64 11-8 98 36 12-3 134 49 13-3 89 65 11-2 9i 43 12-10 104 52 13-1 105 67 1 1-6 95 46 12- 1 1 hi 54 13-7 119 68 II-IO 93 5i 12-7 121 57 13-n 126 70 ii-ii 94 55 12-7 117 61 13-2 9i 7 1 11-2 162 58 12-3 119 67 13-1 92 75 1 1-9 100 59 12-11 96 78 1 1-9 95 66 12-1 100 Seventh Grade 72 12-9 102 3 13-9 121 Sixth Grade 13 13-3 123 24 11-8 143 Seventh Grade 22 13-n no 56 1 1-9 97 25 12-11 118 3i 13-n 100 48 12-6 148 40 13-3 95 Seventh Grade 50 12-11 1 14 45 13-3 130 67 ii-ii 122 56 12-10 122 49 13-n 9i 52 13-8 114 58 13-n 1 13 60 13-6 121 14 No.Yrs. I.Q. Fourth Grade 62 14-1 82 Fifth Grade 27 14-2 85 3i 14-3 88 Sixth Grade 8 14-10 86 27 14-3 72 4i 14-3 no 44 14-n 88 50 14-5 87 70 14-10 82 7i 14- 1 109 Seventh Grade 2 14-2 in 5 14-7 116 7 14-1 no n 14-n 109 12 14-0 112 1 7 14-0 141 23 14-5 99 24 14-3 119 27 14-0 92 30 14-0 ii5 33 14-0 127 35 14- 1 106 38 14-9 88 39 14-5 109 42 14-5 117 43 14-5 93 46 14-2 97 47 14-5 80 53 14-5 99 54 14-10 83 55 14-8 84 57 14-0 93 61 14-0 112 63 14-10 88 64 14-2 92 Eighth Grade 54 14-8 102 59 14-2 104 65 14-6 106 13 yrs. (contd.) 62 13-6 93 65 13-4 128 66 13-8 no Eighth Grade 66 13- 1 1 97 MODERN METHODS OF MENTAL MEASUREMENT 81 the two groups of pupils in the perceptual tests. The same pro¬ cess carried through for the symbol tests provided an index of the relative success of low and high I. 0. in those tests. Then the two indices were compared. Theoretically, if the achievement of low and high I. Q. is nearer together in the perceptual tests than in the symbol tests (as would naturally be the case if the theory of the levels is true), then the index as obtained above for the perceptual tests would be expected to be smaller than that ob¬ tained for the symbol tests. A sample of how such an index is obtained is given in Table VII, and a combined table of a num¬ ber of such indices is shown in Table VIII. Table VII Contrast of Achievement of Low and High I. Q. in Perceptual and Symbol Tests. Chronological Ages io and n Perceptual Tests Symbol Tests Low I. Q. Low I. Q. Scores Me- Scores Case IQ. Score Ranked dian Index Score Ranked 4-2 88 79 79 97 74 4-1 1 88 120 85 87 74 4-17 89 109 95 123 76 4-32 91 95 98 99 87 100.5 4-61 90 103 103 76 97 4-64 9i 98 109 74 99 5-6i 88 1 12 112 101 101 5-65 9i 85 120 74 123 •930 High I. Q. High I. Q. 4-1 108 96 95 84 73 4-5 126 100 96 129 84 4-9 126 hi 100 128 93 4-23 138 106 100 146 no 4-30 114 117 100 93 119 4-33 121 hi 100 no 121 4-38 112 107 101 135 128 4-40 1 19 113 104 132 129 4-47 112 100 106 119 132 4-5i 112 100 106 73 135 4-57 116 hi 107 147 143 108 5-7 152 hi 109 174 146 5-22 151 1 19 hi 194 147 5-32 11 3 101 hi 169 150 5-4i 126 106 hi 150 156 5-44 116 104 hi 121 162 5-46 143 114 113 156 167 5-47 hi 109 1 14 143 169 5-54 136 95 1 17 162 174 5-7i 162 100 119 167 182 6-24 M3 141 138 197 194 7-67 122 138 141 182 197 Me¬ dian 92 144-5 Index .636 82 JAMES LEROY STOCKTON Table VIII Contrast of Achievement of Low and High I. Q. in Perceptual and Smybol Tests Perceptual Tests Symbol Tests Median Index Median Index Chronological Ages 10 and 11 Low I. Q. 100.5 92.0 •930 .636 High I. Q. 108.0 144.5 Chronological Ages 11 and 12 Low I. Q. 98.0 99.0 .875 .60 High I. Q. 1 1 2.0 165.0 Chronological Ages 12 and 13 Low I. Q. 103.5 104.5 .821 .60 High I. Q. 126.0 174.0 Chronological Ages 13 and 14 Low I. Q. III.O 121.0 .834 .679 High I. Q. 1330 178.0 It is clear from the above table that in this study the ratio (index) of achievement of low and high I. Q. is nearer to unity in every case for the perceptual tests than for the symbol tests. This is what would be expected if low and high I. Q. are nearer together in achievement on the perceptual than on the symbol level. This study therefore consists in : (1) Quantitative determination of the intelligence of a given group. (2) Verifying the result by means of teachers’ judgments. (3) Testing the same group by means of (a) a number of tests which are primarily perceptual, and (b) a number of tests which are primarily symbolic. (4) Comparison of perceptual-test results, and symbol-test re¬ sults, on the basis of the criterion. This comparison is made (a) through correlation and (b) through the computation of an index denoting per cent of capacity. By this process it is found (1) that symbol tests surpass per¬ ceptual tests in power of discrimination of degrees of intelligence, and (2) that achievement of high and low intelligence is much closer together in perceptual than in symbol material. MODERN METHODS OF MENTAL MEASUREMENT 83 The conclusion is made that the study offers evidence in favor of the theory of intelligence levels based upon an analysis of qualitative differences in judgment regarded as a mental “com¬ mon factor.” 2. In lower school grades. This study is of the same form as the other one except that the validity of the Binet mental ages and intelligence quotients is assumed without the checking by teachers’ estimates of intelli¬ gence. This assumption was felt to be justified because the whole procedure of determining the Binet results was the same as that used in the first study, and it seems safe to believe that the same validity is present. The value of a second study lies in the confirmatory evidence which it furnishes. It would be expected that the same results as to correlations and indices of relationship between the achieve¬ ment of low and high I. Q. could be looked for, but with the addi¬ tional feature that the contrasts based upon differences in achieve¬ ment in perceptual and in symbol tests would be expected to be less pronounced as a whole in the lower than in upper grades. This is so because if the theory of the levels is true, children of all grades of endowment will differ less in early years before the power of abstraction in any of them has had the chance for development, and consequent differentiation, which comes in later years. The following data will show how this theory works out. Table I gives Binet data (to be used as before as criterion) on 135 lower grade cases. Table I Original Data: Abbreviated Binet in Lower Grades. Case Born Tested Second Grade M.A. I.Q. 1 7/22/12 1/19/20 7- 6 100 2 11/19/12 1 / 19/20 7- 9 108 3 5/19/03 1 / 14/20 6- 6 98 4 1 2/ 9/1 1 1/16/20 7- 0 87 5 6/ 6/1 1 1 / 14/20 9- 1 106 6 10/24/12 1 / 14/20 7- 3 100 7 7/17/12 1/16/20 7- 9 103 8 12/23/11 1/13/20 8- 3 102 9 4/20/12 1/13/20 7- 9 100 10 6/20/12 1/12/20 7- 6 99 11 2/22/12 1 / 12/20 6- 9 85 12 1/12/11 1/16/20 6- 3 69 84 Ca; 13 14 15 16 1 7 18 19 20 21 22 23 24 25 26 27 28 29 30 3i 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 JAMES LEROY STOCKTON Table I (Continued) Born Tested M.A. I.Q. Second Grade (Continued) 3/30/13 2/ 2/20 7- 9 113 5/ 3/i2 1/16/20 7- 9 100 1/21/12 1 / 14/20 6- 9 85 12/ 6/12 1/ 14/20 7- 3 102 1/ 8/12 1 / 14/20 7- 9 96 7/26/12 1/16/20 7- 6 100 8/23/1 2 1/16/20 8- 9 117 8/11/11 1/21/20 9- 6 112 8/24/12 1 / 19/20 8- 3 hi 1/31/10 1/2 1/20 8- 9 88 10/27/11 1/21/20 8- 0 98 2/28/12 1/22/20 8- 6 107 1/11/13 1/22/20 9- 0 128 8/ 1/11 1/22/20 9- 0 106 12/10/12 1/ 4/20 8- 6 120 5/26/12 1/20/20 8- 3 107 6/24/12 1/23/20 6- 3 82 7/14/12 1/22/20 8- 6 113 1/29/13 1/23/20 9- 0 127 4/ 6/1 1 1/30/20 8- 0 9i 7/15/1 1 1/23/20 8- 3 97 10/13/n 1/23/20 7- 3 87 2/20/12 1/22/20 7- 9 98 5/ 10/ 1 1 1/22/20 9- 1 105 6/ 7/1 1 1/22/20 9- 1 105 5/ 9/i 1 1/22/20 9- 0 105 5/ i/ii 1/22/20 8- 9 100 8/ 8/10 1/22/20 7- 3 77 6/ 8/10 1/22/20 8- 1 83 3/24/12 1/22/20 8-10 112 4/ 2/11 1/22/20 9- 0 102 3/ 2/12 1/22/20 9- 4 117 5/ 9/12 2/ 2/20 9- 0 116 2/21/12 1/22/20 8- 0 IOI 1/30/ 1 2 2/ 2/20 8- 3 103 10/ 3/1 1 1/16/20 8-10 107 9/23/1 1 1/ 4/20 8- 0 96 7/ 12/12 1/22/20 8- 3 109 9/27/ 1 1 1/22/20 8- 3 99 2/ 18/ 12 1/22/20 7- 3 92 5/29/12 1/30/20 8- 0 105 Third Grade 12/28/10 1/19/20 8- 6 94 8/ 1/11 1 / 14/20 11- 4-5 135 6/ 7/ 1 1 1/16/20 9- 9 H3 3/26/11 1/15/20 9- 0 102 8/28/11 1/20/20 10- 4 122 12/13/11 1/16/20 9- 0 hi 5/10/12 1/20/20 8- 3 107 3/28/11 1 / 14/20 11- 4 128 10/16/10 1/16/20 10- 5 112 1 0/29/ 1 1 1/14/20 7- 3 87 11/ 1/11 1/20/20 8- 3 IOI 9/10/10 1/20/20 11- 3 120 MODERN METHODS OF MENTAL MEASUREMENT 85 Table I (Continued) Case Born Third Tested Grade (Continued) M.A. I.Q. 66 4/28/11 1/20/20 7- 9 88 67 12/19/11 1/20/20 9- 7 1 19 68 4/ 6/1 1 1/16/20 8- 9 100 69 1/27/ 10 1/ 16/20 9- 4 93 70 8/30/11 1 / 19/20 9- 0 107 7i 11/ 1/11 1/20/20 8- 9 106 72 2/25/11 1 / 19/20 8- 9 99 73 2/25/n 1/20/20 12- 9-5 143 74 5/23/12 1/19/20 11- 0.5 144 75 7/23/12 1 / 19/20 9- 6 126 76 4/ 1/10 1/16/20 10- 1 102 77 2/16/12 1/20/20 9- 0 1 13 78 12/12/n 1/14/20 6- 9 83 79 2/ 3/1 1 1/16/20 9- 1 102 80 7/ 3/io 1/16/20 10- 2 107 81 2/ 4/1 1 1 / 19/20 10- 4 1 16 82 7/21/n 1/16/20 9- 3 109 83 9/26/10 1 / 13/20 8- 6 9i 84 3/24/10 1 / 19/20 8- 3 84 85 7/16/12 1/ 19/20 10- 9 143 86 ii/io/io 1 /i 5/20 9- 4 102 87 9/19/10 1/16/20 9- 6 102 88 8/30/10 1/20/20 10- 0 106 89 7/29/1 I 1/15/20 8- 9 103 90 7/25/10 1 / 12/20 10- 9 H3 9i I 2/ 8/08 1/14/20 12- 5-5 112 92 7/16/10 1/ 15/20 10- 1 106 93 7/ 1/10 1/13/20 9-11 104 94 10/ 2/10 1/15/20 9- 3 100 95 11/24/08 1/13/20 9-11 88 96 4/13/10 1/15/20 n-10.5 122 97 10/30/09 1/15/20 9- 7 93 98 12/ 4/08 1/13/20 IO-II 98 99 3/16/10 1 /i 3/20 9- 5 95 100 1/30/10 1/14/20 10- 5 105 101 2/22/09 1 / 12/20 10- 9 99 102 9/19/10 1/12/20 9- 0 96 103 4/14/10 1 / 15/20 8- 6 87 104 3/20/1 I 1 / 14/20 11- 4-5 129 105 6/28/09 1 / 13/20 9- 6 90 106 I 1/27/09 1/13/20 8- 6 83 107 2/ 4/1 I 1/13/20 11- 6 129 108 5/19/10 1/13/20 10- 9 in 109 12/28/09 1/ 13/20 10- 6 105 no 3/10/09 1/ 14/20 10- 8 98 III 11/ I 2/ 10 1 / 14/20 10- 9 117 1 12 I 1/20/ 10 1/13/20 9- 7 103 1 13 6/12/10 1 / 15/20 10- 4 107 1 14 7/29/10 1/14/20 10- 2 106 115 8/17/10 1 / 14/20 9- 8 103 Il6 3/ 2/1 I 1/13/20 10- 8 120 117 5/ 5/10 1 / 14/20 10- 1 104 1 18 n/19/09 1 / 19/20 9- 7 94 86 JAMES LEROY STOCKTON Table I (Continued) Fourth Grade Case Born Tested M. A. I.Q. 1 19 8/14/10 1/28/20 10- 9.5 115 120 1/ 2/10 2/ 2/20 11- 0 109 121 9/12/08 1 1/20/ 19 10- 8 95 122 5/28/08 n/19/19 10- 2 89 123 5/27/08 11/21/19 9- 4 81 124 7/ 6/08 2/ 2/20 10- 5 90 125 11/10/10 1/27/20 14- 5 155 126 12/28/08 2/ 2/20 10- 1 9i 127 4/ 1/09 1/28/20 10- 8 98 128 11/22/09 1/27/20 14- 3-5 140 129 11/10/08 1/27/20 9-1 1 88 130 8/11/07 11/19/19 9- 0 73 131 6/ 6/ 11 1/28/20 10- 8 123 132 12/15/08 1/26/20 9- 3 83 133 7/26/09 2/ 3/20 11-20 113 134 10/18/09 1/26/20 9-1 1 97 135 4/iS/io 2/ 2/20 10- 5 106 After the Binet data appearing in Table I had been obtained, there was given, as before, a group test consisting of single tests, part of which were primarily perceptual and part symbol. The perceptual tests were (i) symbol digit, (2) picture completion, (3) maze, (4) pictorial sequence, and (5) pictorial identities. These were simply different standardized forms of the same type of tests used in the first study, except for the familiar maze test which does not need description. The symbol tests were (1) practical judgment, (2) opposites, (3) vocabulary. Of the 135 cases for which Binet data are given, 134 took the tests just listed, except that because of an epidemic it was possi¬ ble to give the vocabulary test to but hi cases. Raw data for these cases appear in Table II. Table II Raw Data for Five Perceptual and Three Symbol Tests. Second Grade Perceptual Tests Symbol Tests Case 1 2 3 4 5 Total 6 7 8 Total 1 6 11 0 1 1 19 4 4 2 5 10 4 6 6 3i 6 0 6 12 3 5 7 3 4 1 20 6 6 3 15 4 7 9 6 3 9 34 5 8 10 23 5 8 10 8 7 7 40 7 6 3 16 6 3 8 5 4 2 22 0 0 7 0 11 7 4 2 24 4 5 10 19 8 7 11 6 6 5 35 2 0 9 4 8 1 0 1 14 6 3 8 17 10 6 8 1 0 2 17 0 0 0 0 11 2 3 0 1 1 7 0 0 0 0 MODERN METHODS OF MENTAL MEASUREMENT 87 Table II (Continued) Second Grade Perceptual Tests Symbol Tests Case 1 2 3 4 5 Total 6 7 8 Total 12 5 8 2 1 2 18 0 6 2 8 13 5 9 5 2 1 22 4 5 7 16 14 6 2 3 4 1 16 0 4 6 10 15 6 6 0 6 4 22 0 0 16 7 11 0 5 1 24 5 6 17 6 4 7 6 2 25 3 6 8 17 iS 7 7 0 6 1 21 0 0 5 5 19 8 10 8 5 9 40 5 5 9 19 20 7 10 5 7 3 32 10 5 8 23 21 7 9 5 6 7 34 8 7 8 23 22 7 6 4 4 1 22 6 4 0 10 23 8 8 5 2 1 24 5 6 12 23 24 6 11 7 4 6 34 10 4 9 23 25 6 9 6 6 7 34 8 9 9 26 26 6 9 8 4 6 33 5 5 2 12 27 4 9 5 5 3 26 9 3 3 15 28 7 9 5 6 3 30 7 5 29 7 6 7 4 4 28 4 5 8 1 7 30 6 9 2 6 7 30 2 7 13 22 3i 9 6 3 6 6 30 5 3 12 20 32 3 12 6 7 2 30 5 3 4 12 33 6 7 0 7 5 25 7 5 17 29 34 8 2 0 4 1 15 5 6 5 16 35 3 9 4 I 2 19 3 2 4 9 36 8 8 7 4 9 36 0 6 13 19 37 7 11 7 7 6 38 8 6 3 1 7 38 7 10 6 7 2 32 7 6 14 27 39 7 10 6 7 0 30 0 5 13 18 40 7 6 4 3 2 22 3 4 8 15 41 8 9 8 7 7 39 4 3 6 13 42 4 11 7 5 9 36 4 4 4 12 43 6 8 6 6 4 30 7 4 13 24 44 0 10 5 6 . 5 26 3 4 20 27 45 8 12 5 5 2 32 9 8 17 34 46 6 6 0 2 2 16 2 4 12 18 47 9 9 5 5 3 3i 9 3 48 8 9 2 7 8 34 7 6 8 21 49 7 10 7 7 0 3i 5 6 14 25 50 7 10 2 5 3 27 0 0 1 I 51 7 11 6 6 4 34 0 2 12 14 52 7 6 1 5 5 24 5 6 6 17 53 9 10 3 7 8 37 9 7 12 28 Third Grade 54 6 10 6 5 9 36 9 7 11 27 55 7 12 9 5 9 4i 8 6 12 26 56 8 12 3 6 8 37 10 9 57 6 7 4 3 5 25 8 6 13 27 58 10 10 7 6 5 38 7 6 13 26 59 0 9 4 4 0 1 7 8 5 9 22 60 6 8 7 5 8 34 8 7 61 6 11 4 6 5 32 9 8 62 7 12 8 4 4 35 9 7 20 36 63 8 11 8 5 4 36 6 4 20 30 88 Case 64 65 66 67 68 69 70 7 1 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 9i 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 IIO III 1 12 11 3 1 14 1 15 116 117 1 18 JAMES LEROY STOCKTON Table II (Continued) Third Grade (Continued) Perceptual Tests Symbol Tests I 2 3 4 5 Total 6 7 8 Total 9 10 8 5 7 39 5 7 14 26 8 9 4 4 9 34 10 9 13 32 9 7 3 5 7 3i 8 8 12 28 8 11 4 7 6 36 9 4 15 28 8 12 7 7 4 38 10 6 10 26 6 12 6 7 9 40 7 3 17 27 6 8 5 5 7 31 9 6 9 11 6 7 7 40 8 6 16 7 12 7 7 8 41 10 3 29 8 10 6 7 7 38 10 10 26 46 8 12 7 6 9 4 2 10 9 1 7 36 5 10 3 2 9 29 9 6 9 24 7 11 5 7 4 34 8 9 7 10 7 7 5 36 6 9 17 32 0 10 7 5 7 29 6 5 13 24 6 12 5 6 8 37 6 9 8 11 9 7 7 42 9 7 20 36 9 11 7 7 9 43 10 7 9 26 8 11 8 5 6 38 9 6 25 40 3 9 4 5 6 27 8 5 13 26 9 12 9 6 1 37 9 4 13 26 8 8 6 5 9 36 10 8 22 40 8 12 4 7 7 38 9 7 9 25 8 10 9 5 8 40 7 6 17 30 5 8 6 0 0 19 8 6 22 36 10 10 9 7 6 42 9 8 19 36 11 11 7 6 8 43 9 9 13 3i 9 11 10 7 9 46 10 9 10 29 8 11 7 7 9 42 8 7 20 35 6 11 4 6 7 34 8 6 18 32 10 12 8 7 7 44 9 6 15 30 8 9 6 7 7 37 8 4 20 32 11 11 7 7 8 44 10 8 20 38 6 7 6 7 8 34 10 7 19 36 10 11 6 7 A 38 7 7 23 37 7 12 8 7 7 4i 10 4 7 21 8 10 9 7 5 39 10 7 8 11 6 7 6 38 9 9 13 3i 9 12 6 7 7 4i 10 7 15 32 8 11 8 7 5 39 9 5 20 34 10 10 8 7 8 43 10 8 19 37 8 12 6 7 8 4i 8 7 21 36 9 10 6 6 1 32 5 7 7 10 7 7 8 39 9 7 7 9 6 7 5 34 10 7 26 43 7 11 8 7 8 41 8 5 7 7 7 5 6 32 6 5 20 3i 8 11 4 5 1 29 8 7 9 11 9 6 9 44 9 8 17 34 5 11 6 7 8 37 9 7 8 10 6 7 7 38 9 8 17 34 9 11 7 7 7 41 8 8 21 37 7 10 1 7 8 33 8 8 17 33 8 10 6 6 7 37 9 5 8 10 3 7 7 35 9 7 MODERN METHODS OF MENTAL MEASUREMENT 89 Table II (Continued) Fourth Grade Perceptual Tests Symbol Tests Case 1 2 3 4 5 Total 6 7 8 Total 121 8 10 7 7 4 36 7 9 11 27 122 7 11 5 7 9 39 8 6 18 32 123 7 9 0 6 7 29 8 4 16 28 124 10 12 9 6 8 45 9 8 14 3i 125 7 12 9 7 8 43 10 9 22 4i 126 9 11 9 7 4 40 9 6 20 35 127 7 11 8 7 8 4i 8 10 19 37 128 7 10 3 7 1 28 10 7 23 40 129 9 10 9 6 7 4i 9 9 14 32 131 9 11 9 7 9 45 6 7 1 7 30 132 10 9 3 6 I 2 9 8 8 14 30 133 1 2 11 6 7 9 45 10 9 19 38 134 9 12 6 7 6 40 10 7 21 38 135 9 10 5 6 4 34 8 2 19 29 On the theory expressed at the beginning of this second study that the contrast between high and low I. Q. would be less in lower than in upper grades, one would expect to find coefficients of correlation for perceptual tests and for symbol tests not quite so far apart as they were in the upper grade study, although he would still expect to find that the symbol tests correlated higher with mental age than the perceptual tests did. Examination of data in Table III (below) will show to what degree this expecta¬ tion is realized. Table III Correlation of the Individual and the Combined Group Tests with Mental Age (Binet). I. Perceptual Tests II. Symbol Tests I. Symbol Digit . . 39 I. Practical Judgment .... II. Picture Completion .... . 46 II. Opposites . . 56 III. Maze . . . 39 III. Vocabulary . * . . 72 IV. Pictorial Sequence .... . 47 V. Pictorial Identities . . . . 39 Total Perceptual . . 58 Total Symbol . . 72 Comparison of this table with Table V of the first study shows that the predicted tendency for the correlation coefficients to run lower in lower grades is present especially in the battery of per¬ ceptual tests as compared with the battery of symbol tests. Neither battery shows so high a correlation as was shown by the corresponding battery in the first study. The relative relationship is, however, the same. The perceptual tests are always lower. 90 JAMES LEROY STOCKTON The vocabulary test in this table shows again the highest correla¬ tion found for any single test, but not quite so high as in the for¬ mer study. All of this is significant, but it still needs to be re¬ inforced by the computation of the index showing per cent of capacity in the two types of tests. As before, in making these contrasts, the cases were first dis¬ tributed by chronological age and I. Q. Table IV Chronological Age and Binet I. Q. Case 7 yrs. IQ. Case 8 yrs. I.Q. Case 9 yrs. I.Q. I 7-6 100 4 8-1 87 12 9-0 69 2 7-2 108 5 8-7 106 22 9-11 88 6 7-3 100 8 8-1 102 40 9-5 77 7 7-6 103 15 8-0 85 4i 9-7 83 9 7-9 100 1 7 8-0 96 54 9-i 94 10 7-7 99 20 8-5 112 62 9-3 1 12 ii 7- 11 85 23 8-2 98 65 9-4 120 14 7-8 100 26 8-6 106 76 9-10 102 16 7-i 102 32 8-9 91 80 9-6 107 18 7-6 100 33 8-6 97 83 9-4 91 19 7-5 11 7 34 8-4 87 84 9-10 84 21 7-5 hi 36 8-8 105 86 9-2 102 24 7- 11 107 37 8-8 105 87 9-4 102 25 7-o 128 38 8-8 105 88 9-5 106 27 7-i 120 39 8-9 100 90 9-6 113 28 7-8 107 43 8-10 102 92 9-6 106 29 7-7 82 47 8-0 103 93 9-6 104 30 7-6 113 48 8-3 107 94 9-3 100 3i 7-o 127 49 8-4 96 96 9-9 122 35 7- 11 98 5i 8-4 99 99 9-10 95 42 7-10 112 55 8-5 135 100 9-11 105 44 7-1 1 11 7 56 8-7 11 3 102 9-4 96 45 7-9 1 16 57 8-10 102 103 9-9 87 46 7- 11 101 58 8-5 122 108 9-8 hi 50 7-6 109 59 8-1 hi hi 9-2 117 52 7- 11 92 61 8-10 128 112 9-2 105 53 7-7 105 63 8-3 87 113 9-7 107 60 7-8 107 64 8-2 101 1 14 9-6 106 74 7-8 144 66 8-9 88 ii5 9-5 103 75 7-6 126 67 8-1 1 19 117 9-8 104 77 7-i 1 113 68 8-9 100 1 19 9-5 115 85 7-6 143 70 8-5 107 125 9-3 155 7 1 8-3 106 135 9-10 106 72 8-10 99 73 8-11 143 78 8-1 83 79 8-1 1 102 81 8-11 116 82 8-6 109 89 8-6 103 104 8-10 129 107 8-1 1 129 116 8-10 120 r 131 8-8 123 MODERN METHODS OF MENTAL MEASUREMENT 9i The contrasts which follow are based upon an analysis of score (for the data see Table II) and chronological age and I. Q. (for data see Table IV). The method is the same as that used in the first study. Table V Contrast of Achievement of Low and High I. Q. in Perceptual and Symbol Tests. Perceptual Tests Symbol Tests Median Index Median Index Low I. Q. Chronological Ages 7 and 8 29.5 20.0 .843 .769 High I. Q. 35-0 26.0 Low I. Q. Chronological Ages 8 and 9 30.0 23.0 .789 .718 High I. Q. 38.0 32.0 Indices for other contrasts are as follows: (Index for total perceptual tests differs from that just given above because dif¬ ferent number of cases were used). Perceptual Tests Index Yrs. 7, 8 .805 Yrs. 8, 9 .786 Table VI Symbol Tests 6 and 7 Index .666 .656 Perceptual Tests Index Yrs. 7, 8 .843 Yrs. 8, 9 .789 Symbol Tests 8 alone Index .720 .588 In all of these contrasts the index for symbol tests is smaller than that for perceptual tests. This showing is therefore in all cases favorable to the original proposition that the achievement of low and high intelligence would be found closer together on the perceptual than on the symbol level. It should be noted, how¬ ever, that the contrasts in these lower grades tend to be narrower than the ones previously shown for upper grades. This is in line with the theory previously expressed that mere age itself (as well as difference in high and low I. Q.) makes a difference in achieve¬ ment in perceptual tests contrasted with symbol tests. The study therefore consists in the same steps as those out- 92 JAMES LEROY STOCKTON lined for the first study, and the conclusion from it is the same, with additional evidence of the relationship of high and low school grade achievement. Thus it seems that the quantitative data presented in the two studies strengthen the conclusion pre¬ viously arrived at through the theoretical survey of the field, and through the examination of evidences in the work of other inves¬ tigators. It is fully appreciated that the number of cases used has been relatively small, and that the evidence furnished cannot be conceived to be finally conclusive. It is believed, however, that the evidence is now strong enough to warrant a definite convic¬ tion that further experimentation will confirm the tendencies shown in these studies. The relation of these conclusions to theories of intelligence and of intelligence measurement will be taken up in the next chapter. CHAPTER VI Modern Methods of Mental Measurement I. The evolution of modern methods. I. A SUMMATION OF MODERN TENDENCIES The intention here is not that of giving an exhaustive account of every attempt which has been made to measure intelligence; but rather that of identifying significant modern movements, and of pointing out definite tendencies, which have led to a present prevailing attitude toward the problem. Previous to the early years of the twentieth century, diagnosis of mental subnormality was made mostly either by physicians from the medical standpoint, or by teachers from the pedagogical standpoint. There was very little of the psychological, except as it was implied in the others. Moreover, neither the medical nor the pedagogical diagnosis had much of the exact quantitative about it; but both were made mostly in the form of estimate, per¬ sonal opinion, or approximation, very much akin to such estimates of distance as those expressed in terms of “a stone’s throw/’ “a day’s travel,” etc. There were no standardized units and there¬ fore no reliable, comparable results. It is true that degrees of feeblemindedness were discriminated in such words as idiot, im¬ becile, or the French “debile'’; but the patient called imbecile by one physician might be called idiot or debile by another. There was no common ground upon which the diagnosis was made. The degrees of feeblemindedness were named in words of psycho¬ logical import, but were sometimes defined in physiological or anatomical terms (brain lesion, control of bodily functions, mo¬ tility, locomotion, prehension, appetite, respiration, secretion, cir¬ culation, or bodily stigmata) and sometimes in terms of specific mental functions (sensation, perception, will attention, etc.). All of these attempts to define feeblemindedness, and its de- 94 JAMES LEROY STOCKTON grees, resulted in little attention to the need for defining intelli¬ gence, or for getting at its fundamental nature. It was apparently taken for granted that since intelligence is the opposite of feeble¬ mindedness it was therefore well enough understood what intelli¬ gence is. Yet, both for feeblemindedness and intelligence, no terms at all would have been safer than the ones in use, because the very vagueness of the customary terminology gave a mislead¬ ing impression of definitness. Such vagueness even made it pos¬ sible to confuse feeblemindedness (retarded mentality) with in¬ sanity (unbalanced mentality), a thing which could not happen at the present time except among those entirely uninitiated in the field. It is true that in the latter part of the nineteenth century a movement appeared which had in it more of the psychological and more of the exact quantitative. It is now known, however, that this psychological movement was fundamentally on the wrong track in so far as intelligence was concerned, although it- had in it something which has survived. The movement in ques¬ tion showed two aspects : ( i ) the determination of intelligence through the exact laboratory measurement of individual mental and physical traits found to be correlated with the estimates, opin¬ ions, and approximations previously mentioned; and (2) the de¬ termination of intelligence through the summation of the results of exact quantitative measurement of mental traits regarded as elements. Thus intelligence was tacitly held to be equal to the sum of one’s quantitatively measured sensation, perception, memory, etc. The first of these tendencies (the correlation of intelligence with mental and physical traits) holds its place today as a val¬ uable supplement to the scientific measurement of intelligence itself. The second has been discarded along with the “faculty” psychology out of which it sprang, except that the mental ele¬ ment or trait, regarded as a unit-mental activity, still holds a very important place when viewed from a different angle. However, the real revolution in the definition and measure¬ ment of intelligence came when, through the genius of Binet, all criteria of intelligence (the medical criterion, the social criterion, MODERN METHODS OF MENTAL MEASUREMENT 95 the pedagogical criterion) were made subordinate to a perfected quantitative psychological criterion based upon the theory of gen¬ eral intelligence. The essence of this idea of general intelligence has already been given in the quotations of a previous chapter which deals with judgment as the common factor in intel¬ ligence and with the relation of the separate mental functions to intelligence. The customary exaggerated reliance upon the de¬ termination of amount of intelligence through its correlation with mental and physical traits was reduced to its rightful minor place, and the attempt to determine the amount of intelligence through the summation of mental traits was shown to be faulty. Then a relatively exact quantitative scale for the measurement of general intelligence was made. This scale is too well known to need description here. It was based upon judgment as a common factor in all intelligent acts, and although Binet did not hold ab¬ solutely to the use of problems involving judgment, the follow¬ ing quotation shows that, at bottom, that was his intention. * “As a result of all this investigation, in the scale which we present we accord the first place to judgment; that which is of importance to us is not certain errors which the subject commits, but absurd errors, which prove that he lacks judgment. We have even made special provision to encourage people to make absurd replies. In spite of the accuracy of this directing idea, it will be easily understood that it has been impossible to permit of its regulating exclusively our examinations. For example, one can¬ not make tests of judgment on children of less than two years when one begins to watch their first gleams of intelligence. Much is gained when one can discern in them traces of coordination, the first delineation of attention and memory. We shall therefore bring out in our lists some tests of memory; but so far as we are able, we shall give these tests such a turn as to invite the subject to make absurd replies, and thus under cover of a test of memory, we shall have an appreciation of their judgment.” Binet’s two proposals : ( I ) to make exact quantitative measure¬ ment of general intelligence; and (2) his later adopted plan of grouping together at one age all of the tests normal for that age, *The Development of Intelligence, Vineland Laboratory, page 43. 96 JAMES LEROY STOCKTON have proved to be the dominant features of modern intelligence measurement. The only notable competitor is what is known as the “Point Scale System' 1 which adopts the idea of general intelli¬ gence, but rejects the chronological-mental age classification, and measures intelligence in “points won”. But this proposal has been shown by Otis and by others to be not fundamentally different from the Binet method. Binet’s work was first introduced to this country by Goddard, who made an American revision of it. Kuhlmann and others have also offered revisions; but the last and easily the most uni¬ versally successful and important is Terman’s Stanford Revision. Important variations of the Binet plan appear in the “perfor¬ mance scales” and in group intelligence testing. The former have been referred to in previous chapters, especially as to their relation to levels in intentionally controlled intelligence. It needs to be emphasized here that these scales, built either upon the Binet plan or upon the essentially similar “point scale” plan, have great potential value for the measurement of non-English speaking foreigners, of the illiterate, the deaf, etc., but as general scales of intelligence they fail because they fea¬ ture, in the main, the perceptual level only. Since it has been shown to be probable that both high and low intelligence can work at this level, it might be possible to get differentiation by the use of very many graded and especially carefully standardized tests; but this would not be an economical method in comparison with scales which use more abstract material. Neither would it be logical to attempt entirely to overcome the difficulty by compli¬ cating perceptual tests with abstract factors, although under cer¬ tain conditions this approach is well worth while. Therefore the performance scale is inadequate as a total plan for grading intelli¬ gence, but it remains an essential subsidiary element for use under certain special conditions. Examples of the most commonly known of the performance tests are those of Pintner and Patterson, Healy, Knox, Sten- quist, and Kent. The Porteus maze tests are of this nature also ; but are complicated more than some of the others by abstract requirements. They therefore are proportionately valuable, al- MODERN METHODS OF MENTAL MEASUREMENT 97 though the narrow range of judgment tested by them makes it de¬ sirable that they should be used as an element in a scale with other tests rather than by themselves. As to modern group testing, it may be said that it was first introduced by Otis, that it adapts for group work certain tests similar to the individual Binet tests, and that it involves no new principles antagonistic to the Binet, although Otis suggests sup¬ plementary mathematical bases which provide for what he terms '‘an absolute point scale” in distinction from the point scale of the Yerkes-Bridges type. There can be no doubt that the more rapid work which the group method permits makes it of supreme importance, since it can be used for the bulk of the work with large numbers and the special cases can then be handled through individual tests. Some of the best known of the group tests are those of Otis, and the army tests based primarily upon the Otis tests. The lat¬ ter show the same tendency to divide into perceptual and symbol tests as has already been noted in the individual tests, and the fun¬ damental reason for the division is the same. Illiterates, and for¬ eigners in the army could not be handled on the basis of tests re¬ quiring much use of language. Hence the development of the army group test Beta, and the utilization in the army also of many of the individual performance tests of the type of the Pintner and Patterson, Healy, Stenquist, Porteus, and others. Other group tests of the same general character as the army tests are the Pressey tests, the Haggerty tests, the Myers Mental Measure, the new National Research Council tests, Terman’s Mental Abil¬ ity tests for grades VII to XII, etc. But all mental measurement of today has swung to the Binet principles, and the Binet criterion easily remains the dominating force in modern intelligence measurement. However, the results from the Binet tests, and their variations, are supplemented wher¬ ever possible by other psychological, pedagogical, and neurological data. There is also, where possible, a provision for retests, and for a period of observation of the subject before the final inter¬ pretation is made of the data. Persons with little more than a clerk’s knowledge of the standard procedure can do much in the 98 JAMES LEROY STOCKTON gathering of data, but where serious issues are involved, the interpretation calls for the widest experience and training in psy¬ chology and in the related sciences involved. 2. SOME GENERAL SIDE LIGHTS ON THE DEVELOPMENT OF THE MODERN VIEW. But the modern view has come only as the culmination of a long conflict with the former preconceptions concerning intelli¬ gence. A brief discussion of the most salient points of this con¬ flict will still further clarify the situation. There was for a long time (and one might almost say that there still is) a tendency to cling to the earlier medical and psychiatric conceptions wherein the criteria of feeblemindedness are expressed in physical, medi¬ cal, social, or vague psychological terms rather than in the more definite concept of general intelligence and mental age. Binet’s work was well along in France by 1908, yet in that year “The British Royal Commission on the Feebleminded” defined that class as “persons who may be capable of earning a living under favorable circumstances, but who are incapable from mental de¬ fect existing from birth or from an early age: (a) of competing on equal terms with their normal fellows; or (b) of managing themselves and their affairs with ordinary prudence”. Such a definition, though vaguely psychological as well as social, is open to any interpretation which varying conditions and the personal equation of the physician or the psychiatrist may develop. It has nothing of the stability which is possessed by a mental age estab¬ lished through the use of a standardized scale. But even Tredgold’s original formulation was of the same order, although it included incomplete cerebral development (psychological criterion) as well as mental defect. Even as late as 1914 he defined amentia as “a state of restricted potentiality for, or arrest of, cerebral development, in consequence of which the person affected is incapable at maturity of so adapting himself to his environment or to the requirements of the community, as to maintain existence independently of external support.” Thus in this definition there is the vague psychological criterion, the medical or physiological criterion, the social criterion, and also MODERN METHODS OF MENTAL MEASUREMENT 99 the more modern criterion of "‘adaptation”; and yet all are so indefinite as not to compare in any way with more exact scientific measurement based upon a standard psychological scale. There has persisted also an effort to determine amount of in¬ telligence through the correlation with bodily and mental traits and through the summation of mental traits measured quantita¬ tively. The former is valuable if recognized and given its rightful subordinate position. Much good work has been done along this line as supplementary to diagnosis by the Binet and similar scales. As to the attempt to get at intelligence through the quantitative summation of mental traits, it may be said that this is less and less in evidence. Some of the important places where it has tended to persist are the profile method of Rossilimo (1912), the tachistoscopic method proposed by Netschajeff (1917), and in the Yerkes-Bridges Point Scale. The authors of the latter arrange tests according to individual functions, but that part of their work has had little emphasis or apparent success and the scale has filled an important place through its resemblance to the Binet method, rather than because of the feature under discus¬ sion. Indeed such an effort can only have success when the sub¬ ject is tested, not for the amount of the function, but for his ability to solve problems in terms of the function; and although this may have really been what the Yerkes-Bridges scale was meant to do, the authors do not make it clear that such was their idea. 3. CERTAIN MINOR AND MAJOR VIEWS AND STUDIES IN CONFIR¬ MATION OF THE EXISTENCE OF A COMMON FACTOR FOR INTELLIGENCE. Meumann, Stern, and Ebbinghaus have, in a general way, presented the idea of a common factor, particularly in the defini¬ tions which they give of intelligence. Meumann, as interpreted by Terman, presents a two-fold definition: “From the psycho¬ logical point of view, intelligence is the power of independent and creative elaboration of new products out of the material given by memory and the senses. From the practical point of view, it in¬ volves the ability to avoid error, to surmount difficulties, and to 100 JAMES LEROY STOCKTON adjust to environment.” Stern says that intelligence is “the gen¬ eral capacity of an individual consciously to adjust his thinking to new requirements; it is general adaptability to new problems and conditions of life.” Ebbinghaus, as a result of the Breslau investigation in 1905, came to take a view of intelligence which emphasized the ability to combine dissociated elements into a meaningful whole. He called this “combinative ability”, and de¬ veloped a tentative method for testing it, through asking the subject to fill in elisions in mutilated prose. This method has been further developed in many ways since that time, and is a common feature as a single test among groups of tests in most modern systems. Sentence completion, picture completion, etc., are variations of this test. Intelligence has also been conceived as synonymous with a com¬ mon mental factor called attention, clear awareness, concentration, etc. ; and with other single mental factors ; but it is very easy to believe that Meumann, Stern, Ebbinghaus, and other authorities of major importance support, in effect, the view of Binet which makes judgment the essential and common factor. Where other factors are named it seems clear that their advocates have defin¬ itely, even if unconsciously, identified intelligence with judgment and simply have made a further identification of what they con¬ ceive the central element in the process. But the most convincing evidence of the existence of the com¬ mon factor is the mathematical proof found in the correlational studies of such writers as Abelson, Burt, and Hart and Spear¬ man. As to the essential nature of this generally conceded com¬ mon factor there is a certain amount of disagreement. Abelson (1911) leaned toward “clear awareness”, the lack of which in any case he refers to cerebral impairment. Burt supports essen¬ tially the same view when in his earlier work (1911) he combines Binet’s tendency to emphasize the power of voluntary attention, with McDougall’s view of the physiological factors in attention. But Burt also emphasizes judgment, reasoning, seeing relations, as the most fundamental things in intelligence, and suggests a scale of tests featuring all processes from the highest to the lowest (regarding reasoning as the highest). Thus he demands both MODERN METHODS OF MENTAL MEASUREMENT IOI complexity and range, with reasoning given the most weight. The difference between this view and that which has been urged in these pages lies in the fact that Burt appears to see levels of intelligence delimited by quantity of judgment ability, while herein the levels discriminated depend upon quality of judgment ability. Spearman and Hart (see British Journal of Psychology, March 1912) discuss three views of the common factor: (1) non-focal, (2) multi-focal, and (3) uni-focal. In the first, abilities are re¬ garded as absolutely specific, and therefore non-correlating, ex¬ cept in cases where, by chance, like elements happen to be present in the different performances. In the second, faculties, types, or levels are regarded by them as furnishing foci of likenesses, and therefore of groups of correlations, such as might be expected from Thorndike’s theory of levels of sensitivity, association, and dissociation. In the third there is assumed to be a common factor in all performances, and therefore all performances may be expected to correlate to the extent to which the common factor is present. While admitting the essential truth of the Spearman and Hart position, there are several observations which may be made. ( 1 ) The non-focal theory can, as they say, probably safely be dis¬ carded. Modern psychological investigation by Coover, Angell, Rugg, and others supports this conclusion. (2) The opinion of Spearman and Hart that the multi-focal theory is necessarily an¬ tagonistic to the uni-focal theory is not necessarily true if one ad¬ mits the view that the common factor, judgment, extends through all intelligence; but that in a certain part of the field the quality of judgment is mechanical (thus differentiating mechanically con¬ trolled intelligence), and in another part of the field, purposive (thus differentiating intentionally controlled intelligence). Thorndike’s sensitivity and association levels would then seem to belong to the field of mechanically controlled intelligence, while his dissociation (free idea) level, would seem to belong to inten¬ tionally controlled intelligence. Moreover in the field of inten¬ tionally controlled intelligence, the common factor, judgment, may again be conceived as determining levels according to the 102 JAMES LEROY STOCKTON quality of the mental elements (sensations, percepts, images, sym¬ bols) between which relationships are discerned. (3) The theory thus interpreted does not involve “faculty” psychology if the men¬ tal elements considered are thought of as unit-activities of a total mind. (4) The whole theory supports the Binet view. It is true that Binet called the common factor judgment, and Spearman and Hart (and others) define it in terms of cortex energy, etc., but this may be viewed as only a case of psycho-physical parallelism in the analysis of which one person speaks in terms of the mental correlate, and the other in terms of the physical correlate. When the cortical change comes, the judgment is exercised. It is not necessary to postulate that one is caused by the other, but only that one accompanies the other. Hence, there is a very generally supported view of the existence of a common factor, which factor can, roughly at least, be meas¬ ured objectively and expressed through the use of an age scale; and the Binet scale is the basis and universally used expression of the theory. II. Possible results of the theory upon methods of mental measurement. It should now be clear that the key to the theory proposed by the thesis is ( 1 ) such a definition of intelligence as makes non-predictable variation the paramount thing in it; (2) the acceptance of the theory of a common factor re¬ sponsible for non-predictable variation, and quantitatively measur¬ able in terms of an age scale ; (3) an appeal to the literature and to original quantitative experimentation in support of a new under¬ standing of intelligence based upon an analysis of qualitative dif¬ ferences in the common factor. Primarily the qualitative differ¬ ences appealed to are referred to differences in power to handle the concrete and the abstract. The reader should hold it definitely in mind that no claim of originality is here made for the theory that intelligence is conditioned by different degrees of control over the concrete and the abstract. It has been shown that the intuitive psychology of the layman ferreted out that fact long ago. But an attempt has here been made to show the connection of this popular MODERN METHODS OF MENTAL MEASUREMENT 103 conception with that of psychological levels differentiated by vary¬ ing abilities to manipulate judgment in terms of the mechanical and the intentional, and in terms of different unit-mental-activities within the intentional. Assuming that a certain amount of proof has been offered in favor of the hypothesis of levels conditioned by these qualitative differences in the common factor, and that there is at least a strong probability that the theory is true, the following practical bearings of this conclusion upon methods of mental measurement are suggested. I. EMPHASIS UPON THE VALUE OF THE LANGUAGE TEST. One result of the study is to emphasize the value of the lan¬ guage test as an intelligence test. By language test is not meant the mere mechanical flow of words; but instead a genuine com¬ mand of language as the tool of thought. There has been a grow¬ ing tendency in intelligence measurement to try to get away from the language test. This tendency has been one reason for the devel¬ opment and use of performance scales even with subjects who labor under no handicap with regard to language ability. How¬ ever, the desire to minimize the language factor has had its origin largely in the fact that owing to their ability to put many words together, the feebleminded have often been found to give an im¬ pression of an intelligence which they do not really possess. Ideas expressed in language have two phases : (a) the word, or symbol, and (b) the meaning of the word or symbol. The feebleminded often have the first of these without the second. When the me¬ chanical use of language can be sufficiently guarded against, lan¬ guage ability becomes one of the best evidences of intelligence, of ability to work on the symbol level in contrast to the perceptual level. 2. TENDENCY TO THE DEVELOPMENT OF MORE DIAGNOSTIC SCALES OF INTELLIGENCE BASED UPON THE SEPARATE SCALING OF QUALITATIVE DIFFERENCES IN THE COMMON FACTOR. It seem likely that as a supplement to the single scale which now features mechanically controlled intelligence, intentionally controlled intelligence, and reproductive (pedagogical) intelli- 104 JAMES LEROY STOCKTON gence, together, there will tend to appear also separate scales of these three types of intelligence constructed upon the same prin¬ ciples. In fact such an outcome is already in evidence. Repro¬ ductive, or pedagogical scales have become common; and De Sanctis, even as early as 1911, suggested the distinction between “lower ideation” and “higher ideation”. This distinction cor¬ responds in intent at least roughly to the mechanically controlled intelligence and intentionally controlled intelligence which have been discussed. The idea has also of late appeared in concrete operation in the work of Link and others in employment psychol¬ ogy. The investigators in this field have found it necessary to develop separate scales of technique and of intelligence ; or, in other words, separate scales of mechanically controlled intelli¬ gence and of intentionally controlled intelligence. The very fact that practical application of tests has brought out the demand for three types of scales is in itself a degree of proof of the theory as outlined; and there is added proof in the tendency of modern students of intelligence to stress the intentional and immediate so¬ lution of problems as the central thing in intelligence. It is the central thing in the highest type of intelligence, the type dif¬ ferentiated by judgment of the intentionally controlled quality. The present Binet scale, or any other perfected upon the same principles, can give a result which shows only a total mental age. One can ascertain that a subject is excellent or normal or feeble¬ minded by comparison with chronological age, but neither the Binet mental age nor the intelligence quotient derived from it shows specifically wherein the excellence or the defect of the subject con¬ sists. The situation is similar to that which has developed with pedagogical scales. Take for example the field of handwriting. Thorndike’s scale of “general merit” in handwriting is directly comparable with the Binet scale of general ability in intelligence. The scale measures a total ability, but does not attempt to be analytic or diagnostic as to particular faults. Such a scale has many values (and always will have), as “general merit” hand¬ writing scales have abundantly proved ; but it has been necessary for diagnostic purposes to develop supplementary scales of sep- MODERN METHODS OF MENTAL MEASUREMENT 105 arate elements of handwriting excellence such as the Ayres di¬ vision into slants and the more extended Freeman division into a larger number of parallel scales of important elements. With an opportunity to scale a pupil’s handwriting by the several scales of the elements, that pupil’s special difficulty can be located and the correct assistance given. It seems probable therefore that there should be developed a scale or a system of scales which would measure separately not only mechanical, pedagogical, and purposive intelligence, but which also (in purposive intelligence at least) would measure separately the ability to judge (a) in terms of perceptual ma¬ terial, and (b) in terms of imaginal material, and (c) in terms of symbol material. Such a series of scales would be much more diagnostic than the general scales now in existence, would help correctly to place subjects in life, and, by more nearly locating the defect would lead the way to’ a more effective study of possible remedies for mental defects. This is extremely important, for it is not impossible that the present view of the permanency of mental defect needs at least partial revision. At least they need very extended and critical testing, and the more definite analysis which would be possible through the qualitative extension of the scales would be a very important as¬ sistance in this work. 3. INCREASED TENDENCY TO SPECULATE UPON THE PROBLEM AS TO WHETHER THE DEVELOPMENT OF INTELLIGENCE CEASES SOON AFTER ADOLESCENCE. The emphasis upon judgment as the common factor in intelli¬ gence, and upon levels of intelligence determined by qualitative differences in the mental elements concerning which judgment is rendered, may throw light upon the vexed question as to whether the development of intelligence ceases at about the chronological age of sixteen or eighteen as the Binet theory tends to hold. All experiments with Binet material and procedure have tended to sus¬ tain this view. They have not brought out reliable evidences of increment beyond the point mentioned. Hence there is the in¬ ference that mental growth reaches approximately its maximum, io6 JAMES LEROY STOCKTON as does physical growth, a few years after adolescence. Of course there may be after this time an increase in the ability to get the most out of the intelligence which one has, just as one may learn to make better and better use of his physique even after physical growth ceases ; but to distinguish between increase in intelligence itself and increase in one’s power to use a fixed amount of intelli¬ gence appears to some persons as, in a sense, a begging of the question. For, off hand, one tends to believe that if a college senior can solve more real problems than he could when he was a high school senior, then by that very fact he is to be judged actually more intelligent. By the same criterion he might be found more intelligent when he is chronologically forty than at the time of his graduation from college. Yet the point in question is exactly the one just raised. Does a person show more success in problem-solving at forty than at sixteen or eighteen? Possibly the answer lies in asking whether one means more problem-solving or better (or different) problem¬ solving. Thus perhaps it is again a question between quantity and quality. In this thesis the view has been supported that the power to deal with abstractions must show development around about twelve years (chronologically) or else the subject is marked as mentally inferior. That is, he must begin to exhibit a certain quality of judgment at about that time or he is defective. By the time he is sixteen or eighteen the Binet tests seem to show that his power of abstraction is developed about as far as it ever will be, that significant increase in intelligence beyond this age does not seem to occur. Perhaps this appears to hold (a) because the pecu¬ liar quality of abstract judgment (organizing power) required to earn the new increment of intelligence is not tested by the Binet tests; and (b) because the peculiar quality of abstract judg¬ ment in question is so rare that it is easily missed by any system of tests. There is a type of abstract synthesis which requires not minutes or hours, but months, years, or a lifetime. Many of the world’s supreme problems have been solved by men who have shown a peculiar, dogged persistency in pursuing an idea until its relation to other ideas and their relation to it became apparent. Speed is not an element in such a feat. The essence of the MODERN METHODS OF MENTAL MEASUREMENT 107 achievement is judgment of a peculiar organizing type, which sees through insignificant details and finally seizes upon the really sig¬ nificant factors. It may be, therefore, that after types of intelli¬ gence are differentiated on the qualitative basis of perceptual, imaginal, and symbolic, it will be necessary to distinguish a higher qualitative differentiation within the symbolic itself, which the limitation of brief time for testing, and incomplete insight into values, have left still untapped by any exact quantitative measure¬ ment. Perhaps it is too elusive to be tapped. At any rate, one may, if he so desires, speculate upon its existence, and he is likely to do so if he is not fully satisfied with the other view that intelligence ceases to develop at the age of sixteen or eighteen years. This speculation concerning a real increase in intelligence itself, an increase based upon qualitative differences in the power of abstract thought, is possibly not antagonistic to the essential Binet principles but merely supplementary to them. III. Summary. In this thesis it has been held : 1. That the problem of intelligence is within the problem of adaptation. 2. That not all adaptation, but only non-predictable adaptation is intelligent. 3. That in all non-predictable adaptation there is a common factor, judgment. 4. That sometimes the quality of judgment is mechanical and sometimes intentional. 5. That if the term intelligence is used at all with reference to mechanically controlled judgment, the qualified expression mechanically controlled intelligence should be used. 6. That intentionally controlled judgment should be called intentionally controlled intelligence. 7. That intentionally controlled intelligence itself exists in levels determined in popular language by different degrees of con¬ creteness and abstractioness involved in the exercise of the com¬ mon factor. 8. That the terms concrete and abstract are only popular ex¬ pressions for the more technical psychological terms which desig¬ nate unit-mental-activities. io8 JAMES LEROY STOCKTON 9. That there could be discriminated as many levels in inten¬ tionally controlled intelligence as there are distinct unit-mental- activities ; but that it is expedient to discriminate but three levels — the perceptual level, the image level, and the symbol level. A degree of proof of the existence of the levels has been offered (a) by reference to existing literature, and (b) by original quanti¬ tative research. The conclusion is drawn that more diagnostic testing of intelligence could be done if the exising age-scales of general intelligence were supplemented by scales which test for ability on the different levels. The main contributions are (a) greater insight into the defini¬ tion and nature of intelligence, and (b) the pointing of the way toward more diagnostic measurement of intelligence through the provision for measurement based upon the levels determined by qualitative differences in the common factor, judgment. TYPICAL GENERAL REFERENCES Abelson, A. R., Measurement of Mental Ability of Backward Children, Br. Jr. Psychol, 4, 1911. Adams, G. P., On the Negative and Positive Phototropism of the Earthworm, Am. Jr. Physiol., 9, 26. Angell, J. R., Chapters from Modern Psychology, Longmans, 1912. . , An Introduction to Psychology, Holt, 1918. Baldwin, B. T., Differentiation Between Psychological Experi¬ ments and Mental Test., Report of Am. Psychol. Asso., 1916. Baldwin, J. Mark, Mental Development, Macmillan, 1894. . , The Development of Animal Psychology, Congres. int. de Zool, 1914. . , Social and Ethical Interpretations, Macmillan, 1897- 1902. Balz, A. G. A., Dualism and Early Modern Philosophy, Jr. Philos., Psychol, etc., 1918, 15. Bell, J. C., Recent Literature on the Binet Tests, Jr. Ed. Psychol, 3, 1912. Binet, Alfred, et Simon, Th., Sur la necessite d’etablir un diagnostique scientifique des etats inferieurs de lintelligence, L’Annee psychologique, 1915, 163-190. See also pages 191-244, and 245-336. . , Le Developement de lintelligence chez les enfants, L’Annee psychologique, 1908, 1-94. . , Nouvelles recherches sur la mesure du niveau in- tellectuel chez les enfants d’ecole, L'Annee psychologique, 1911, 145-201. Binet, Alfred, Les Signes physiques de lintelligence des enfants, L’Annee psychologique, 1910. . , Les Frontieres anthropometriques des anormaux, Bu. Soc. Et. Ps. Enf., 1904. . . Attention et adaptation, L’Anne psychologique, 1900; 248-404. Boardman, H., (Compiler), Psychological Tests, a Bibliography, N. Y., Bureau Ed. Experiments, 1917. IIO JAMES LEROY STOCKTON Bobertag, O., Ueber Intelligenzpriif ungen, Zeitschrift fur ange- wande Psychologie, 1911, 5. Bohn, G., Actions tropiques de la lumiere, c. r. Soc. Biol., Paris, t. 55- . . Theorie nouvelle du phototropisme, c. r. Academy Science, t. 139. Bonser, F. G., The Reasoning Ability of Children, Columbia University, Contributions, No. 37. Book, W. F., Analysis of Some of the Higher Thought Pro¬ cesses, Psych. Bub, 1912, 9. Brigham, C. C., Two Studies in Mental Tests, Psychological Monographs, 1917, 24. . , An Experimental Critique of the Binet-Simon Scale, Jr. Ed. Psychol., 5, 1914. Buckingham, Correlation Between Ability to Think and to Re¬ member, Schl. and Soc., 1917, 5. Burt, C., Experimental Tests of General Intelligence, Br. Jr. Psychol., 3, 1909. . . , Experimental Tests of the Higher Mental Processes, Jr. Exper. Ped., 1911, 1. Cams, P., In Reply to Dualistic Conceptions of Mind, Monist, 1918, 28. Cellerier, L., L’Habitude dans l’education, L'Educ., 1916. Chase, H. W., Consciousness and the Unconscious, Psyc. Bub, 1916. Chotzen, F., Die Intelligenzprufungsmethode, Zeitschrift fiir angewande Psychologie, 1912, 6. Clifford, W. K., Lectures and Essays, London, 1886. Cohen, M. R., The Distinction Between the Mental and the Physical, Jr. Phil., Psychol., etc., 1917, 14. Colvin, S. S., The Attitude of the Child in Learning, N. E. A., I9I4* Coover, J. E., Formal Discipline, Psych. M011., 1912, No. 87. For other material on the same topic see also bibliographies in this book. Dashiell, J. F., Sixteen Origins of the Mind, Am. Jr. Psychol., 1918, 29. Dearborn, W. F., The Measurement of Intelligence, Psyc. Bui., I9I7> 14; De Busk, Height, Weight, Vital Capacity, and Retardation, Ped. Sem., 1913, 20. Decroly and Degand, Archives de Psychologie, Jan., 1910. MODERN METHODS OF MENTAL MEASUREMENT hi De Sanctis, S., Mental Development and Measure of the Level of Intelligence, Jr. Ed. Psychol., 1911, 2. Descoeudres, A., Equete sur l’evaluation subjective des quelques tests Binet et Simon, Archives de psychologie, 1917, 16. Dewey, John, Duality and Dualism, Jr. Philos. Psychol., etc., 1917> T4- . , Imitation, Encyclopedia of Education (Monroe), Macmillan, 1911. . . The Reflex Arc Concept in Psychology, Psyc. Rev., 1893- 3- . , How We Think, Heath, 1910. Doll, E. A., A Brief Binet Scale, Psyc. Clinic, 1917, 11. . , Anthropometry as an Aid to Mental Diagnosis, Vine- land, N. J., 1916. . , The Interpretation of Anthropometric Measurements, Jr. Psycho-Aesthenics, 1915, 20. Downey, J. E., Standardized Tests and Mental Inheritance, Jr. Hered., 1918, 9. Dunlap, K., An Outline of Psychobiology, Johns Hopkins Press, 1917. Ebbinghaus, Ueber eine neue Methode zur Priifung geistigen fahigkeiten, etc., Zeitschrift fur Psychologie, 1897, 13. Esquirol, Des Malades mentales, II, p. 340. Fabre, F. H., The Wonders of Instinct, London, 1918. Fernald, Guy C., An Achievement Capacity Test, Jr. Ed. Psyc., 1912, June. Franz, S. I., Handbook of Mental Examination Methods, Jr. Neur. and Mental Diseases Pub. Co., 1912. Fisher, S. C., The Process of Generalizing Abstraction and Its Product the General Concept, Psyc. Mon., 1916, 21. Galton, Head Growth in Students at the University of Cam¬ bridge, Nature, 1888, 38; 1889, 40. . , Cambridge Anthropometry, Nature, 1890, 41. Gilbert, Researches on Mental and Physical Development of School Children, Yale Psychological Studies, 1894, 2. . , Researches upon Children and College Students, Uni¬ versity of Iowa, 1897, 1. Goddard, H. H., Psychology of the Normal and Subnormal, Dodd, Mead and Co., 1919. . . The Binet and Simon Tests, 1905 Series, Vineland, 1908. . . Measuring Scale of Intelligence, Vineland, Jan., 1910. 1 12 JAMES LEROY STOCKTON Goddard, H. H., Four Hundred Feeble-minded Children Classi¬ fied by the Binet Method, Ped. Sem., 1910, 17. . , The Revision of the Binet-Simon Scale, Vineland, 191 1. . , The Form Board as a Measure of Intellectual Devel¬ opment in Children, Training School Bulletin, 1912, 9. . , Standard Methods of Scoring Binet Tests, Vineland, April, 1913. . , The Reliability of the Binet-Simon Measuring Scale of Intelligence, Proc. Fourth International Congress of School Hygiene, 1913, 5. ......... Two Thousand Normal Children Measured by the Binet Measuring Scale of Intelligence, Ped. Sem., 1911, 18. Gray, W. S., Descriptive List of Standard Tests, Elementary School Journal, 1916, Sept. Groos, The Play of Animals, Chapman and Hall, 1898. Groszmann, M. P. E., The Individual Child, Scribners, 1917. Hall, G. Stanley, The Founders of American Psychology, Apple- ton, 1912. . , Adolescence, Appleton, 1904. Hachet, Souplet P., La Genese des instincts, Paris, 1912. Hart and Spearman, General Ability; its Existence and Nature, Br. Jr. Psychol., 1912, 5. Healy, William A., Pictorial Completion Test, Psychol. Rev., 1914, 21. . . The Individual Delinquent, N. Y., Little Brown, I9I5- Healy and Fernald, Tests for Practical Mental Classification, Psyc. Mon., 1911, 54. Herrick, C. Judson, An Introduction to Neurology, Saunders, 1915- Holmes (etc.), Descriptive Bibliography of Measurement in Ele¬ mentary Subjects, Harvard Bulletin, 1917. Honingswald, R., Principien der Denkpsychologie, Kant. Stud., 1913-8. Hough, The Classification of Nervous Reactions, Science, N. S., XLI. Huey, E. B., The Psychology and Pedagogy of Reading, N. Y., 1908. . , Backward and Feebleminded Children, Baltimore, Warwick and York, 1912. James, William, Psychology, Holt, 1890. MODERN METHODS OF MENTAL MEASUREMENT 113 Jennings, H. S., The Behavior of the Lower Organisms, N. Y., 1906. Johnson, W. E., Analysis of Thinking, Mind, 1918, 27. Klemm, Otto, A History of Psychology, Scribner, 1914. Kohs, S. C., The Stanford (1915) and the Vineland (1911) Re¬ visions of the Binet Scale, Psyc. Rev., 1917, 24. . , The Binet-Simon Measuring Scale for Intelligence, an Annotated Bibliography, Jr. Ed. Psychol., 1914, 5. Knox, H. A., A Scale Based Upon the Work at Ellis Island, Jr. Am. Med. Asso., March, 1914. Kuhlman, F., A reply to Dr. L. P. Ayres, etc., Jr. Psycho- Aesthenics, 1911, 16. . , Binet and Simon Method for Measuring Intelligence of Children, Jr. Psycho-Aesthenics, 1911, 15. . , Some Results of Examining 1000 Public School Chil¬ dren with a Revision of Binet-Simon Tests of Intelligence by Untrained Teachers, Jr. Psycho-Aesthenics, 1914, 18. . , The Binet and Simon Tests of Intelligence in Grad¬ ing Feebleminded Children, Jr. Psycho-Aesthenics, 1912, 16. . , A Revision of the Binet-Simon Scale for Measuring Intelligence of Children, Mon. Sup. Jr. Psycho-Aesthenics, Sept. 1912. . , A Further Extension and Revision of the Binet- Simon Scale, Jr. Criminal Law, 1918, 8. . , What Constitutes Feeblemindedness, Jr. Psycho- Aesthenics, 1915, 19. Kulpe, Outlines of Psychology. Ladd, Psychology, Descriptive and Explanatory, Scribners, 1909. Ladd and Woodworth, Elements of Physiological Psychology, Scribners, 1911. Lange, K., Ueber Apperzeption, Leipzig, 1912. Lashley, K. S., Recent Literature on Animal Behavior, Psyc. Bui., 1914, 11. Lindley, A Study of Puzzles, Am. Jr. Psychol., 8. Lillie, R. S., What is Purposive and Intelligent Behavior, Jr. Phil. Psychol., etc., 1915, 12. Lloyd, A. H., Psychophysical Parallelism, Jr. Phil. Psychol., etc., 1917,14. Loeb, J., Comparative Physiology of the Brain and Comparative Psychology, N. Y., 1900. . . Concerning the Theory of Tropisms, Jr. Exper. Zook, 151, 4. JAMES LEROY STOCKTON 114 Loeb, J., The Mechanistic Conception of Life, Chicago, 1912. . , The Organism as a Whole from a Psychochemical Viewpoint, Putnam, 1916. McKenzie, J. S., Laws of Thought, Mind, n. s. 1916, 25. McMurry, F. M., How to Study, Houghton Mifflin, 1909. Marbe, K., Zur Psychologie des Denkens, Fortsc. d. Psychologie, 1914, 3- Marratt, R. T., Anthropology and University Education, Rep. Brit. Asso. Adv. Sc., 1916. Marshall, H. R., The Relation of Instinct and Intelligence, Br. Jr. Psychol., 1912, 5. Mead, The Relations of General Intelligence to Certain Mental and Physical Traits, N. 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