Aside from the strictly motor and physical tests those devised were mainly of so-called intellectual character: measurements of speed and accuracy with which certain definite tasks could be accomplished. They were, moreover, very simple in character, not necessarily related to the work of daily life, with only a single or but a few trials made on each individual.

Tests of affective and volitional factors were slower in developing. Little account was taken of interests, instinctive and emotional characteristics, att.i.tudes, adaptation, methods of attack, limits of ability after practice, or many other aspects of individuality which later work has shown to be important.

The next step in the development of tests consisted in the cooperative effort to standardize the nature and methods, the conditions and mode of record. Many hands had part in this process, until in recent years, through publication, comparison and discussion of the subject, fairly uniform principles of technique, record, and treatment of measures have been agreed upon. This made possible the comparison of results secured by different investigators, and facilitated the statistical treatment of the data, so that later work might profit by what had already been tried or accomplished by earlier workers. After many years of this sort of cooperative work, another series of studies was inaugurated to attempt what has come to be known as "testing the tests." These studies proceeded by examining into the degree to which the various tests correlate with each other, with other indications of the individual's ability, with age, s.e.x, health, education, school standing, special training, etc. Such questions as the following will suggest the problems involved in "testing the tests."

1. Which of the various tests correlate with each other?

2. What correlation exists between mental and motor abilities?

3. Do the tests measure fundamental qualities or general powers of the individual, or specialized capacities, or perhaps mainly the effect of general or special training?

4. If they measure general qualities, which of the existing tests are the best for this purpose?

5. How many trials are needed to afford a reliable index of the individual's ability?

6. What are the princ.i.p.al incidental factors that influence the result of tests?

7. Which tests are most easily influenced or disturbed by extraneous factors?

8. Can tests of the simpler laboratory type be used to indicate the individual's ability as shown in his daily work and play?

9. How simple or complex should the various tests be in order to give the best results?

10. How many tests, and which, are required to give a fairly correct picture of the individual's psychological make-up?

11. To what degree do preliminary trials indicate the final capacity of an individual?

12. Does the intercorrelation of tests change in any way with practice, repet.i.tion, and familiarity with the material?

13. Just what mental functions may the particular tests be said to measure?

14. How important are these functions in practical, educational and vocational life?

15. By what amounts and in what various ways do individuals differ among themselves in such abilities as the tests measure?

16. Are there other important aspects of psychological const.i.tution and equipment for which there now exist no adequate tests?

The investigation of these numerous problems has resulted in the acc.u.mulation of a considerable literature of mental tests. Many of the earlier forms of tests were abandoned because of their unsatisfactory or meaningless character. Others have been retained and improved in form, and many new ones are constantly being devised and elaborated, described and standardized. The precautions to be observed, the instructions to be given, and the methods of record and interpretation have been presented in various books and manuals. The tests have been developed for more and more complex functions, and now relate not only to relatively simple capacities but to highly elaborate and subtle forms of achievement. As rapidly as is consistent with accuracy, norms and standards of performance for different ages, school grades, vocational requirements, etc., are being acc.u.mulated and reported. Typical charts of age norms in selected tests are given in the Appendix.

As the tests have thus developed they have been organized for a variety of special purposes, such as for school measurement, educational diagnosis, clinical examination, laboratory experiment, and more recently for the purposes of vocational guidance and selection. Among the first of these to develop systematically, and also the ones with the most immediate vocational application, are the graded intelligence scales, which shall be our next concern.

GRADED INTELLIGENCE SCALES AND NORMS

An important step in the history of general tests is represented by the acc.u.mulation of norms and standards of performance for the different selected tests, and the arrangement of scales of tests with increasing difficulty, as further aids in fixing the individual's status.

After a standardized and tested form of test has been selected, norms of performance are acc.u.mulated by applying the test to large numbers of persons of the same general type. The cla.s.sification may be on the basis of age, school grade, occupation, nationality, etc. In this way it becomes possible to determine for a given individual how he compares with other members of his group; whether he is above or below the average, and how far; whether he would belong among the best ten, or the poorest ten, or the third ten, etc., of one hundred selected at random. Such norms also reveal to what degree the tested ability varies with the other factors, on the basis of which the group was selected, as age, s.e.x, education, size, health, race, etc.

As rapidly as reliable norms are established, it becomes possible to select for each age, school grade, occupation, etc., a set of tests which the average person of that age, schooling or calling should be able to perform to a certain known degree of proficiency. Failure to accomplish this indicates performance lower than that expected and in so far as success is dependent solely on mental ability, indicates inferior capacity. Similarly, ability to do more than the average or normal record requires indicates a capacity that is precocious, rare, and superior.

In this way are derived standard graded scales which represent a decided advance in the science of psychological diagnosis. There are three rather different forms in which attempts have been made to secure such scales. In one form the scale consists of a series of steps, each step consisting of different sorts of performance; that is, different tests or tasks are used.

These tasks are arranged in groups, each group representing tests which should be pa.s.sed acceptably by individuals of the given age, school grade, etc. In another form of scale the type of task is the same throughout, but the different points on the scale are represented by increasingly difficult specimens of material. The scale thus presents graded steps of difficulty in doing the same general sort of thing. In the third form the task remains precisely the same throughout, and performance is measured in terms of the time in which the task can be completed and the accuracy which is displayed. Sometimes, in scales of this type, although the instructions are always the same, the test is performed with varying degrees of approximation to a qualitative standard, and the steps may then consist of these graded qualitative achievements.

As representative of the first form of scale we may refer to the widely used Binet-Simon scale for the determination of mental age. Whatever we mean by intelligence, it is a characteristic which is essential to vocational activity. It is furthermore a characteristic which normally tends to increase in its degree or manifestation from infancy up to at least ten or twelve years of age. Beyond that point there are, to be sure, striking individual differences in that characteristic which we call intelligence, but beyond this point it does not seem so dependent on the physical age of the organism. Five-year-old children tend to be pretty much alike in intelligence. At least, the change from five years to seven years is commonly attended by very apparent growth in this respect, and a five-year-old is more like other five-year-olds in the things he can do than he is like seven-year-olds.

Experiment and observation show that the ages up to ten or twelve tend to indicate rather definite mental status, in the long run, although, to be sure, children of a given age vary considerably from one another. But beyond this point the age of an individual is not by any means an indication of the sort or degree of ability to be expected of him. The further we go beyond this point, the less significant becomes the mere statement of the individual's age. We may thus indicate the mental attainment of a child of less than twelve years by stating the average age of children who can do the things, know the facts, display the abilities that he can. This figure we will use to indicate his _mental_ age as distinguished from his _chronological_ or _physical_ or _actual age_. A record-blank which enumerates the tests comprising the Binet-Simon scale is given in the Appendix. Those who may be interested in using this or similar scales should familiarize themselves with some of the many books and manuals that have been written concerning them, the methods of using them, their characteristic results and their evaluation. These scales will be again considered in a later section, when we discuss the measures of general intelligence as they relate to vocational guidance and selection.

Other scales than the Binet-Simon series have been proposed, and this series has itself undergone modifications at the hands of later investigators--changes calculated to render it more reliable and adaptable.

Much work is now being done in the attempt to develop scales or sets of tests which will reveal characteristic differences among people whose mentality has gone beyond the point which the juvenile scales reach.

The work of Trabue in standardizing the "completion test" so that individuals may be quant.i.tatively compared on the basis of it may serve as an example of the second form of scale. This particular test consists in requiring the individual to supply meaningful words or phrases in the blank s.p.a.ces formed by mutilating logical text. It is similar to the simple exercise sometimes found in elementary text books of grammar and spelling.

It seems that the ability to supply the missing words or phrases quickly in such mutilated material calls for the exercise of a type of ability which correlates to a high degree with most other measures of intelligence.

Individual differences as shown by school grades, age, opinion of teachers, estimates of a.s.sociates, results of other mental tests, etc., are readily and with considerable reliability revealed in the individual's ability to perform this type of test. This investigator has, after much preliminary labor, constructed a form of this test in which the material gradually increases in difficulty from beginning to end. Efficiency in the test may be measured by the point one can reach in the text in a given time. This test has been standardized, not on the basis of physical age, as in the case of the Binet-Simon scale, but on the basis of school grade, from the second grade through the high school, some four or six years beyond the point where the Binet-Simon scale ceases to be useful. A copy of this test is also given in the Appendix. Those who wish to use it should consult the original description of it, for technique, precautions, norms, and interpretation.

A good example of the third form of scale is to be found in Sylvester's standardization of the "form-board" test. The "form-board" is one of the most useful tests in detecting intellectual defect that is so p.r.o.nounced as to const.i.tute the individual a "mental defective." Out of a solid base board are cut various geometrical forms, such as diamonds, stars, squares, triangular blocks, etc. These blocks are placed alongside the base from which they have been cut. The task is that of replacing all the blocks in their appropriate places, with the greatest possible speed. The test tends to reveal characteristic defects in understanding instructions, perceiving the general and specific situations, profiting by experience, recognizing form and size and other s.p.a.ce relations, etc. The individual may work blind-folded or may use his eyes.

In the standardized form the sizes, shapes and positions are uniformly adopted and the technique of instruction and procedure is specified. Under these conditions the time required to complete the task by normal children of the ages five to fourteen years has been recorded. Sylvester presents a curve based on the examination of 1,537 normal children. The curve shows the average time of performance for each age and also indicates the range of performance for each age. In the case of a given individual it is thus easy, by referring to the standard table of norms, to determine whether he is up to the normal record for his age, whether he is within the normal range of variation for this age, and how deficient or precocious he may be in this respect. Tables of this type are now being acc.u.mulated for a great variety of single standard tests.

In addition to scales of this type, which proceed by setting for the individual a graded series of tasks and determining his success in their accomplishment, there is a further type of graded scale which is now represented by several standard specimens. This is the type of scale which is designed to afford an instrument for the measurement of such products as the actual work of the individual incidentally yields. Thorndike's "Scale for the Measurement of Handwriting" is the model on which many of the later scales of this type have been based. In this scale actual specimens of handwriting are arranged in a graduated series in such a way that the steps from specimen to specimen are equally appreciable or noticeable, and in this sense uniform. When such a scale extends from an actual zero point, it is possible to "measure" the quality of handwriting in quite the same way as that in which one measures the height of an individual or the length of a table. The quant.i.tative measure consists in the statement of the number of stages which intervene between that quality of product represented by the specimen and the zero point of the scale. The position a.s.signed to the specimen being measured is determined by moving the specimen along the graded series of standards until a point is reached where the specimen seems, on the basis of direct inspection, to belong. Such scales have been formulated for various special forms of school work, such as handwriting, drawing, arithmetic, literary composition, mechanical construction, etc. By such means it is possible not only to measure the "general intelligence" of the worker, but also his actual ability in creating a definite type of product. There seems to be no limit to the possibilities of scales of this form, and their value in determining the more definite and particular capacities, whether from the point of view of original endowment or from the point of view of the effects of training, is obvious.

These various scales for measuring general intelligence have been used chiefly for the purposes of educational diagnosis, in determining the degree of backwardness of children in the grades, their need for special educational attention, or the hopelessness of further pedagogical effort with them. But it is obvious at once that tests of this type are of great use to an employer in eliminating, from among the candidates for work, those who are hopelessly mentally defective, feeble-minded, and irresponsible. There are many sorts of work in which the employment of feeble-minded persons, unrecognizable as such by their physical traits or by a casual inspection, not only entails loss and annoyance but may const.i.tute a positive danger and constant menace to those who rely on the defective individual. Such work as that of delivery boys, messengers, domestic servants, nurses, elevator operators, drivers, motormen, etc., may be cited as instances of work into which the feeble-minded easily slip, unless there is some standardized means of recognizing them.

The importance of detecting these incompetents and keeping them from work in which their irresponsibility means economic waste and personal and social danger is of distinct vocational interest. Studies of cases brought to the Clearing House for Mental Defectives in New York City show that of the first two hundred and eighty-one feeble-minded women of child-bearing age, about two-thirds had been engaged in some form of economic labor in which their incompetence was distinctly dangerous to those a.s.sociated with them. The following table shows how these two hundred and eighty-one feeble-minded women had been employed:

Living at home and a.s.sisting at simple tasks 94 Domestic service (families, bars, hotels, etc.) 67 Engaged in factory operations 21 Living in inst.i.tutions, reformatories, asylums 20 Prost.i.tutes 30 Laundresses 5 Working in stores, clerking, errands, etc. 5 Nursemaids 9 Odd jobs 6 Married and keeping house 11 Housework, with relatives 13

The investigators originally reporting these data write as follows: "These defective women had borne eighty-nine illegitimate children, which were acknowledged and could be somewhat definitely located, and sixteen women were illegitimately pregnant at the time of their examination at the Clearing House. Twenty-four of the two hundred and eighty-one had married and these had borne forty-six legitimate children. The average mental age of the illegitimate mothers was nine years."

The employment of feeble-minded women as domestics, factory operatives, laundresses, clerks, and nursemaids const.i.tutes not only a nuisance to the general public, but a real source of inefficiency and danger to the community. Graded scales for the measurement of intelligence will have amply repaid the labor devoted to their formulation if they aid us in the proper segregation and vocational supervision of the mentally defective.

The feeble-minded boy is more likely to be observed in the natural course of things, because of the more strictly compet.i.tive types of work into which boys customarily go, but it is far from realized how much loss of property, life, and general happiness is entailed upon the community by the indiscriminate employment of untested boys and men as floating employees.

But the vocational value of the graded intelligence scales and norms is not limited to the work of detecting and eliminating the feeble-minded. Many of the tests as now standardized yield measures of intelligence, capacity and comprehension ranging far above the level which const.i.tutes the borderline of mental defect. Some of them reach somewhat higher than the average intelligence and capacity of the college freshman. It is thus possible, through the use of the graded scales, to measure in quant.i.tative terms the general intelligence as well as various more special capacities of applicants and candidates for positions for which general intelligence is the chief requisite. Such tests are now used in many places in the selection of clerical workers, telephone operators, stenographers, waitresses, motormen, salesmen, office help, inspectors, watchmen, soldiers, and special types of factory workers. Thus Trabue reports a study in which Professor Scott tested thirty efficiency experts employed by a large industrial concern in New England. Ten psychological tests were used, including a completion test. The men were also judged on the basis of their relative abilities by the members of the firm. The combined tests correlated with the combined judgments, giving the very high coefficient of .87. The completion test alone yielded a coefficient of .64. From the point of view of vocational selection we may expect the principle of the graded intelligence scale to become increasingly valuable as more and more norms are established. The first definite contribution of vocational psychology is thus not so much toward the guidance of the individual worker as for the guidance of the employer who may be required to select from a number of applicants those whose general intellectual equipment is most adequate. But we shall later have occasion to point out a further contribution which this makes possible, in so far as it may enable us to cla.s.sify the operations involved in various types of work and to align these operations and tasks along the general intelligence scale. Such alignment will enable us to specify the approximate degree of general intelligence which a given position demands, and thus, in the case of the simpler tasks, afford a means of vocational guidance as well as vocational selection.

CHAPTER IV

THE PSYCHOGRAPHIC METHODS

THE INDIVIDUAL PSYCHOGRAPH

Another application of mental tests has a very direct interest for vocational psychology. This is the method of the "psychograph," as it is commonly called. The French and German psychologists especially have been active in advocating the practice of submitting to careful and detailed experimental examination the physical and mental characteristics of men who have achieved marked success in their chosen vocations. By the application of this clinical method to men of superior attainment it is hoped that light may be thrown on the psychological foundations of their genius and, in general, on the relation between mental traits, as shown in the results of psychological tests, and actual success in life's work. This psychographic method represents the earliest methodical attempt to differentiate the various vocations from one another on the basis of special apt.i.tudes and characteristics, as distinguished from the factor of general intelligence. Dr. E. Toulouse has already published reports of such examinations or psychographs in the cases of Zola, Dalou, and Henri Poincare. It is the intention of this investigator to continue this line of work, utilizing from time to time such refinements of technique as may be available. As an ill.u.s.tration of the psychographic method, an account of the study of the eminent mathematician, Poincare, may be given in some detail.

The investigation of Poincare took account of such special topics as heredity, development, physical condition, sensory acuity, various kinds of memory, attention, imagery, reaction time, a.s.sociation of ideas, language and handwriting, character, habits and opinions. Although the tests followed a technique which the investigator recognized to have been quite imperfect and fragmentary, they are said to have yielded results quite sufficient to characterize the intellectual type of the man. The account of the tests is followed by a synthesis in which is attempted a general picture of Poincare's type and an interpretation of the conditions of invention and speculative genius.

From the point of view of heredity, development and general vital characteristics Poincare was found to resemble most his mother and grandmother, who, with collateral relatives, are said to have shown special apt.i.tude in mathematical calculation. Several male members of the family have had successful careers in neurology, law, meteorology, politics and mathematics. Poincare's development was not precocious, although he was bright and showed, when quite young, mathematical ability of an unusual order. His history, up the age of thirty years, at which time he was elected to the Academy of Sciences, was not unlike that of many other mathematicians whose freedom from the necessity of experiment allows them to make rapid progress. He was at one time troubled with rheumatism, and in his childhood suffered from an attack of diphtheria, followed by paralysis.

This attack is said to have profoundly modified his nervous system, perhaps providing the neuropathic basis for traits shown later in life, such as awkwardness, restlessness, flighty attention, distractibility and general sensori-motor deficiency.