INDIVIDUAL DIFFERENCES: THEIR DISCOVERY AND MEASUREMENT
QUESTIONS TO BE ANSWERED IN MODULE 3
1. How did Cattell contribute to the beginning
of the testing movement?
2. What were Binet's contributions to the testing movement?
3. What Were the different factor analytic theories which explained intelligence?
4. When and how did group testing begin?
5. What were the differences between Spearman and Thurstone's theories?
6. How did Yerkes' contributions make him one of the first comparative as well as first clinical psychologists in America?
7. What was the mental health movement?
THE TESTING MOVEMENT
Galton did not devise what today are known as mental tests, but he did show interest in analyzing individual differences. The different characteristics of the mind have always been the central concern of psychology and assessing the different ways of thinking was soon to be investigated. The term "mental tests" eventually came to mean "intelligence tests," because the first successful mental tests, those of Binet, presumably tapped global and general mental functioning rather than different mental components. This is an example of how practical considerations can move a science ahead while at the same time restricting its sphere of activity in such a way as to produce social dissatisfaction. Practical successes are frequently gained at the expense of something else. Mental tests acquired public popularity and scientific attention only after several practical applications. The demonstration by Cattell that persons capable of college work could be identified; the work of Binet, who was commissioned to identify which children could profit from formal schooling; and the selection by and other psychologists during the First World War of inductees for military training were examples. Then mental testing mushroomed out of all proportion, and certain disadvantages became patently apparent.
Americans seemed to want to eat their cake and have it too. They wanted both to solve problems and to maintain certain democratic ideals. But in the attempt to solve one problem they were led to the creation of new problems. The solution of the first was sometimes branded as a cause of the second. This is partly what happened in the field of mental testing. Intelligence tests were designed to eliminate crowded school conditions. Those children needing individualized or specialized instruction were identified by the tests. Tests were originally used to eliminate class distinctions. Later, however, these very tests were attacked as the causes of class divisions, lowered self esteem and restricted creativity of children. Individualized instruction had emerged independent of mental tests. Later, however, these same tests helped to make individualized instruction a success.
Interest in mental tests arose from two different sources -- the German experimental laboratories of the nineteenth century and the English comparative and descriptive psychology, especially as represented by Galton. German psychologists, primarily under the leadership of Wundt, were investigating problems of attention, perception, sensation, and learning. The reaction time was the standard measurement used in these problems. During the eighteenth century, work on the personal equation revealed significant differences among persons in the speed with which they perceive and respond. The variation among individuals was not, at first, a subject for investigation, but the variation among different mental functions within the same person was explored. Wundt and his colleagues busily identified the varying mental processes of sensation, attention, judgment, and response. The complication experiment yielded reaction times for the component processes. This was determined indirectly by subtracting the reaction times for simple processes from the longer times for more complex processes. It was, to say the least, a rough but ingenious method.
James McKeen Cattell, the American student of Wundt, convincingly argued that subjects differed in the speed with which they responded to simple stimuli. There was a constant in the variations; the constant was the person. Wundt thought the variation resulted from experimental errors and he was not excited about the prospects of investigating individual differences. Cattell persisted. He wrote his dissertation on the topic and thereby became the first in a long line of investigators to combine laboratory methods with a study of individual differences. He was convinced, following the work of Helmholtz, that the differences were personal rather than differences in laboratory presentation. Wundt tenaciously held to a generalized human mind; Cattell clung just as tightly to the belief that persons varied. The structure of the mind had become so important to Wundt as to be invariant; the processes, or experimental procedures, were what varied. For Cattell, the procedures were relatively constant, at least for one individual or for similar kinds of individuals. His 1890 paper on mental tests provided explicit methods for identifying differences in mental functioning among persons.
After completing his degree with Wundt in 1887, Cattell went to the University of Pennsylvania and then to Columbia University in 1891 where, for sixteen years, he contributed to the development of a psychology department which became preeminent in the investigation of mental measurements. Cattell was an impressive man, second only to his contemporary, G. Stanley Hall, as an organizer, founder, and leader of American psychologists. He founded the Psychological Review, the Psychological Monographs, and the Scientific Monthly. He inaugurated the American Men of Science, which is still the major biographical reference on leading American scientists. He founded the Psychological Corporation, still one of the foremost test publishing companies in the world. He was elected to the National Academy of Science and was the first psychologist to be so honored. He urged the inclusion of anthropology, psychology, and education as sections within the American Association for the Advancement of Science (Joncich, 1968).
Cattell's tests were not very useful. Although he introduced them in an attempt to predict academic success at the University of Pennsylvania. The tests leaned too heavily in the direction of psychophysical and sensory dimensions. With the possible exception of "recalling a list of words" (or numbers), no items were similar to those eventually used in intelligence tests. Nevertheless, Cattell's interest in testing and individual differences led to his other major interest, the identification of eminent scientists. This interest, too, he shared with Galton and later with Terman who was studying the development of genius. A new country fashioning a new frontier needed human potential, and the identification in the United States of persons of talent was of the same practical importance then as it was in the 1950's when another frontier, the space age, created an intensive search for merit scholars. As Taylor (1911) reports, President Teddy Roosevelt addressing a conference of governors, remarked that "The conservation of our national resources is only preliminary to the larger question of national efficiency (p. 5)."
During the first part of this century, evaluative programs received widespread endorsement. On the one hand, less accomplished offsprings of eminent parents could feel less guilty; they were just not so bright. And on the other hand, ability testing opened doors previously closed to thousands of young middle and lower class geniuses. But eventually the class lines broke and all but the top and bottom classes became the masses. Charges surfaced that a special elite was being developed. Identifying the gifted was criticized as favoring the privileged classes, threatening the masses, and preserving the status quo. The development of an educated elite was prevented by several events -- the influx of immigrants needing acculturation; the publication of John Dewey's book, Democracy and Education; and the passage of the Land Grant Morrill Acts which provided practical and technical higher education for all classes. In the 1960's, efforts were directed toward identifying the culturally disadvantaged and the learning disabled.
First Individual Intelligence Test. A second origin of mental measurements was the study of higher mental processes. Alfred Binet, a French psychologist, had worked in the mental hospital at the Salpetriere, had become the Director of the psychological laboratory at the Sorbonne, and had written extensively on thinking and cognitive development. His work on abstract thinking was more consistent with the Austrian act school than with German experimental psychology.
The Commissioner of Education for the Paris school systems turned to Binet to solve a practical problem, namely, how to identify pupils who might better profit from individualized instruction rather than from formal education in overcrowded public schools. Many pupils were performing considerably below average, but it was not easily apparent which of these were lazy and which possessed mental handicaps. Binet and his collaborator, Simon, proceeded in an ingenious manner to empirically identify those mental skills which are common among different aged children. They asked teachers to name those activities performed by the average child for that grade. For example, could the child count numbers, name colors, define words, cut paper, etc.? The identified tasks were then actually presented to a sample of pupils for that grade. Those items found to be reliable and characteristic of that age were grouped together. The successful performance of a task would then indicate the age level of a particular child. Those children functioning at a lower than average grade level were then given specialized instruction.
Subsequently, in the United States, Lewis Terman, a public school teacher who had obtained his doctorate with G. Stanley Hall, and was teaching at Stanford University, standardized the Simon-Binet test on American children. The newly standardized test, called the Stanford Binet, identified the gifted and retarded and became the criterion against which other tests, both individual and group, were standardized.
Theoretical disputes regarding the nature of mental tests, the nature of intelligence, or both soon surfaced. The Binet tests were supposed to measure a general trait which, presumably, by virtue of a single score, reflected the capacity of a child to adapt or adjust to a wide variety of problem situations. Presumably, Binet himself never defined intelligence or defined it as such. Tuddenham (in Postman, 1962, p. 489) states that it was Goddard who probably substituted for Binet the idea of a singular faculty of psychology with an hereditary base. On the other hand, an English psychologist and a doctoral student of Wundt's, had written a paper in 1901 on the general and specific factors of intelligence. Spearman, however, claimed that Binet was really talking about intelligences, not an intelligence (Murchison, 1930, v. 1, p. 320). After leaving Wundt, Spearman studied with Kulpe at Wurzburg and with G. E. Mueller at Gottingen and then went in 1907 to the University of London.
Early in his efforts to deal with the problem of general mental ability, Spearman attempted to devise a method for computing a correlation coefficient. After some effort, he discovered that Galton had already resolved the problem in a more acceptable fashion. Although Spearman favored Galton's solution and disbanded his own efforts, he did devise a rank order correlation coefficient which has since been called by his name.
His interest in correlations led Spearman to an analysis of the interrelationship among a number of correlation coefficients; and he devised a method of factor analysis to account for the accompanying variance. The common factor "g" in the intercorrelation matrices is what he called general intelligence, and the specific factor "s" was that which was unique to any particular test, thus, his two-factor theory.
L. L. Thurstone at the University of Chicago challenged this two-factor theory as a solution to the problem of intelligence. He proposed that there were several intelligences, all relatively independent of each other; and he used a method of factor analysis different from that of Spearman to discover groups of traits or abilities which accounted for the variance in intercorrelation matrices. Since statistical variability increased as a function of age, Thurstone maintained that extrapolation of growth curves downwards would reveal a Zero point of variability, coinciding at or before the age of birth (Goodenough, 1949, p. 146). This point of view was never widely supported, but it represented an attempt to place mental measurements upon a ratio scale whose prerequisite is an absolute zero point. His group (or multi) factor approach however, did gain wide acceptance. A successful application of this technique is his Primary Mental Abilities test which was and is a popular instrument for assessing intelligence.
The controversy over general vs. group factors in intelligence continued on into the 1930's, when Wechsler constructed a new individual intelligence test which successfully competed with the Stanford Binet. Wechsler, a clinical psychologist at Bellevue Hospital, working with psychotic patients, became convinced that mental functioning was characteristically different among different mental patients. For example, a bright person might display a high level of abstract reasoning during a psychotic disturbance while at the same time reveal depressed motor performance. Wechsler's tests were designed to tap basic mental capacities. There were two general capacities, "verbal" and "performance" abilities and five subtests corresponding to special factors within these general areas. The Wechsler test then yields 13 scores -- 10 subtest scores, a verbal I.Q., a Performance I.Q., and a Total I.Q.
The third stimulus to the development of mental tests came at the beginning of World War I, when induction stations were processing American men at the rate of several thousand a day. Psychologists were commissioned to produce, if possible, a substitute for the Binet test, scientifically preferable but administratively impossible. It was of monumental importance to quickly identify those men who might profit from military training and separate them from those who could not. Robert M. Yerkes, a comparative psychologist from Harvard, Minnesota, and then Yale University, headed the task force charged with finding a solution to this problem. The committee constructed paper and pencil items they hoped would correlate with general intelligence. They administered these items, along with Terman's recently standardized Stanford Binet test, to a large number of men. Those items which correlated with the Binet and therefore predicted it, became the first group test, and was called the Army Alpha. After the construction of the Army Alpha and the Army Beta, those psychologists trained in psychological testing proceeded to administer tests to 1,726,000 men in groups and 83,000 individuals. The testing revealed 500,000 illiterates, of which 8,000 were recommended for discharge due to low intelligence (Reisman, 1966, p. 110).
Review material on psychological testing.
Robert M. Yerkes (1876-1956).
In the small town of Breadysville, Pa., near Philadelphia, Robert M. Yerkes was born and grew up. Bakan (1966, p. 9) claims that American behaviorism sprung from rural and small town soil in the United States. Yerkes was America's first really comparative psychologist. He was also America's first truly quantitative psychologist, and he was the first clinical intern. Although he was identified with the basic tenets promulgated by John Watson, he was not the leader of behaviorism.
Yerkes obtained a bachelor's degree at the little-known college of Ursinus. He then ventured to Harvard for a Ph.D. degree under Muensterberg in 1902. That was a few years before the St. Louis Exposition where Muensterberg served as the Vice President of the International Congress of Arts and Sciences. Yerkes stayed on at Harvard and taught the new psychology there. While there, he had contact with the largest number of great minds America had probably assembled in one place at one time -- James, Royce, Peabody, Santayana, Muensterberg, Palmer, Holt, Perry; the list seems endless. No wonder, then, that Yerkes became psychology's renaissance man!
During his Harvard tenure, Yerkes began his professional career by working in the psychopathic ward of the Boston State Hospital. Ernest E. Southard, director of the psychopathic department, had recommended him for the position (Murchison, 1930, v. 2). Yerkes developed here his point scale of intelligence, a method of mental measurement competing with the Binet Scales, and adapted later by the more popular Wechsler 1930's scales.
Yerkes was at Harvard until the outbreak of World War I in 1917. As president of the American Psychological Association, he was asked to head the team of psychologists working on the Army Alpha. This assignment was crucial to the war effort. Except for the pioneering work done by Binet and Goddard and Stern on children's intelligence, inappropriate for use with considerably older war recruits, there was little to go on. The Binet Scales were the only possible ones for use. Of more practical concern, however, was the problem of how to adapt the Binet scales for use with thousands of recruits entering the induction centers each day. Quite aside from the physical impossibility of lining up that many people, there was lack of trained personnel to administer, score, and report the results. An ingenious solution was clearly needed. Yerkes and his team of psychologists discovered the means for carrying this out. Group tests were thus born.****
Yerkes had begun his psychodiagnostic work and, in fact, became the first clinical intern in the United States while at Harvard. A young professor, he attracted the attention of Elmer E. Southard, Professor of Neuropathology in the Harvard Medical School. Southard had organized the Boston Psychopathic Hospital in 1912, and had asked Yerkes to be the psychologist, a position he held from 1913 to 1917, while he was at the same time teaching at Harvard. Yerkes became, then, the first psychologist at the first hospital established for the purpose of the clinical training of psychiatrists. He was the first person to be trained as a clinical psychologist. Ironically enough, clinical internship began with a comparative psychologist. He is perhaps best remembered now for the primate laboratory named in his honor in Florida called the Yerkes Primate Research Center with Emory University.
Southard and Boston Psychopathic Hospital
It was at Boston Psychopathic that Southard also introduced the idea of psychiatric social workers. Southard got the idea of having social workers serve as a liaison between the hospital and the home by Adolph Meyers who had "encouraged his wife to visit the homes of his patients (Alexander, 1966, p. 377)." During World War I, a course of lectures on psychiatry was given to social workers at Smith College (Schneck, 1960, p. 158). One of Southard's better-known students, Karl Menninger, was inspired by Southard to write The Human Mind, a book which for several decades served as the standard lay introduction to clinical psychiatry, and probably did more than anything else to make psychiatric and psychological concepts and jargon part of the everyday vocabulary of the general public. Menninger was inspired to this endeavor by Southard.
The train of influence, then, is from Southard to Yerkes and Menninger. Yerkes developed the more quantitative side of clinical psychology and Menninger advanced the more psychiatric side. In 1923, Menninger sent a letter to 26 psychiatrists in the United States soliciting interest in an orthopsychiatric association (Lowry, 1948, p. 190). A number of persons active in criminal child work met on January 12, 1924, at the Institute of Juvenile Research in Chicago. The first convention was held later the same year, and Healy was elected the president. Healy had organized, in 1909, the Juvenile Psychopathic Institute and had obtained Grace Fernald as the first psychologist. Fernald was later among those who formed in 1917 a separate, though shortlived, American Association of Clinical Psychology as a reaction to the heated debates arising between psychology and psychiatry. These debates were prompted by psychiatrists who questioned the legitimacy of calling in psychologists as "specialists" (Reisman, 1966, p. 132).*****
These early pioneers in clinical psychology worked in hospitals, schools, and clinics. Their activities paralleled simultaneous developments in medicine, on the one hand, and in lay activities on the other hand. Freud, at the turn of the century, was just developing both the technique and theory of psychoanalysis. In 1909, G. S. Hall invited Freud to address a group of psychologists at Clark University. This encounter stimulated intense interest in psychoanalytic theory in the United States, which has not subsided even to the present day.
Mental Health Movement
Concurrently, Clifford Beers, a layman, who had been hospitalized as a mental patient, expressed dismay at the unusual conditions of mental hospitals, and made every attempt to arouse professionals to the critical need for correcting a deteriorating situation. It was William James, among other psychologists, who encouraged Beers to muster public support for a lay organization. The Mental Hygiene Movement emerged in 1908 independently and almost simultaneously with clinical psychology, psychoanalysis, and the development of Gestalt and behavioristic theory.
During this brief period, American psychology abruptly shifted from a study of the generalized human mind to the techniques of individual adjustments. McDougall lost the nature-nurture debate with Watson. The structural atomists lost as Gestalt psychology generated growing interest. Psychology absorbed the best of all fields into the framework of the new functional psychology. This meant that psychology was becoming applied and practical as well as whole and motivated.
Psychology in America had found, in the psychophysical methods, the normal curve, variability, and a new methodology for describing psychological phenomena. Correlational studies and descriptive studies abounded. Although never intended to answer questions of cause and effect, many believed that high correlations explained questions that continued to plague the psychologists. What was the nature of mental processes, of consciousness, of emotion and attitudes? Answers to these questions were still being sought in the laboratories; experimental studies attempted to explain differences in perceptions, feelings, expectations, and attentions.
Idiographic vs. Nomothetic Psychology
Psychology was divided then as now between two different approaches -- general and applied psychology.General psychology was committed to a nomothetic descriptive psychology, though the methods were often experimental. The experimental work was carried on by Wundt in Germany and by his indefatigable disciple, E.B. Titchenor in America, who cared little for mental measurements but claimed much for a psychology which would identify and describe elements of consciousness. The subjects were trained introspectors who reported their sensations as free as possible from interpretation and judgment. This experimental work paralleled that of the literary writer, novelist, and poet, also attempting to observe and describe as accurately as possible the awareness of present or the recollection of past sensations. This parallel is made explicit by Milicent Shinn, the first American psychologist credited with conducting a child observation as published in her Notes on the Development of a Child (1893-1899) and Biography of a Baby (1899). Shinn explained her interest in child observation as an outgrowth of the "notebook habit," the tendency to write things down which she developed when editor of literary magazines in college. This makes a good observer, she claimed. Other developmental psychologists had the same point of view. Shinn's cousin, Edmund C. Sanford, author of the first successful experimental laboratory manual, trained as a literary person and graduated as the class poet at the University of California. G. Stanley Hall, mentor and co-editor with Sanford of the American Journal of Psychology, was a descriptive psychologist. B. F. Skinner also prides himself on the fact that he is non-theoretical; he was awarded a master's degree in English literature.
Those psychologists interested in the structure of the mind and the formulation of descriptive statements, men like Wundt and Titchener, appear similar to the literary and developmental psychologists like Hall, Sanford, and Shinn, and the descriptive scientists like Louis Agassiz. Joseph LeConte, who studied under Agassiz, was instrumental in influencing some of the early literary psychologists, Shinn and Sanford. It was actually LeConte who suggested the idea of a child observation to Shinn (Shinn, 1899, pp. 249-50).
One is tempted to suggest that there is some relationship among structuralism, poetry, and classicism on the one hand, as opposed to applied psychology on the other. Wundt and Titchener, who stood for classicism within psychology, were considered traditional and conservative and frowned upon research designed only for practical and applied ends.
On the other side were psychologists bent primarily toward the applied, who sought practical ends for their discoveries or ideas. There's was a pragmatic psychology, which eventually became dominant in America. We mean later to consider this other more applied point of view in psychology and how it arose from interest in education and philosophy rather than from laboratory work. James, Dewey, Angell, Carr -- all were deeply involved in educational problems, either the training of teachers or the administering of programs. They directed their energies towards educational activities, consistent with the American notions of democratic principles, and the dream of advancing a new American cultural frontier. Of this group, William James was the older, wiser, and surely more loved than the rest.
But we turn next to different ways in which psychology became systematized. The theoretical structures which emerged organized a wide body of facts and suggested hypotheses to explain the relationship among data. We have previously examined two of the early systems in psychology -- structuralism and functionalism. These points of view gave direction to data collection and exploratory studies. Next we look at those major psychological theories which elicit both controversy and allegiance from researchers and scholars.
NOW TEST YOURSELF WITHOUT LOOKING AT THE READING.
Circle those answers which are correct (one or more) or fill in the blank spaces.
1. Cattell was a founder of numerous things. In
this regard, he was similar to:
2. Catell believed that individual differences were caused by:
a. experimental errors
b. subject differences
c. equipment characteristics
d. accidental variations
3. Group paper and pencil tests first began with the tests of:
c. World War I
d. Spearman's two factor theory
4. Wechsler designed an intelligence test which presumably measures:
a. one general intelligence
b. two major intelligences
c. three major intelligences
d. none of the above
5. In 1909, when psychology was just beginning to come into its own in the United States, G. Stanley Hall brought which well known psychologist to a national conference held at Clark University?
6. The two factor theory of intelligence maintained that there was (were):
a. one general or "g" factor
b. one specific or "s" factor
c. only one kind of intelligence
d. two kinds of intelligences
7. The controversy about whether intelligence could be explained either as a general or as a group factor was illustrated by the controversy between which two men:
a. Wundt and Cattell
b. Binet and Terman
c. Wechsler and Rorschach
d. Spearman and Thurstone
8. The method of analyzing a set of intercorrelated performances into many independent variables is knows as:
b. factor analysis
c. analysis of variance
d. null hypothesis
9. Yerkes was the natural person to head the psychological committee in World War I because he was:
a. president of the APA
b. a leading authority on intelligence testing
c. a military officer
d. a behaviorist
ANSWER KEY ON PAGE 37
8 or more correct, go to Module 2
Less than 8 -- complete exercises on next
7. Psychological Review; Psychological
Monograph; Scientific Monthly
2. German Laboratories; English comparative psychology 3. Cattell
8. Galton; Terman
9. common or general intelligence
NOW TAKE PROGRESS CHECK 2
1. Cattell was interested in identifying eminent
scientists. In this regard his interests were
similar to what other investigators of the
development of genius?
c. both of the above
d. none of the above
2. Cattell was responsible for introducing the
mental test while he was at which university?
3. Which of the following is not one of the
mental tests used by Cattell?
a. naming colors
b. pressure causing pain
c. bisection of a 50 cm. line
d. recalling the dates of historical events
4. In the decade of World War I, which of the
following became established?
a. Watsonian psychology
b. Gestalt psychology
c. intelligence testing
d. all of the above
5. Which of the following is not an individual
a. Stanford Binet
b. Primary Mental Abilities
6. The two factor theory of intelligence was proposed by:
7. Thurstone developed a Primary Mental Abilities Test which was based on his theory of intelligence. That theory was called:
a. one factor
b. two factor
d. none of the above
8. During World War I when mental tests were first introduced to screen Army recruits, the man most responsible for research in this area was:
ANSWER KEY ON PAGE 37
7 or more correct, take
Less than 7 -- instructor conference.
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