Aptitude test

“ In the intelligence test the aim is to ascertain the subject’s general capacity; in the trade test, to discover his present ability or degree of skill in some special direction. Capacity, as has been previously pointed out, is only to be measured in terms of demonstrable ability, so that in the application of trade tests, although limited in their scope to a single class or kind of ability, there is also obtainable as a by-product a partial measure of the subject’s mental capacity. ”

“ The final proof of reliability in a test can come only by actual trial of that test upon men of various degrees of demonstrated ability in the trade or profession concerned. What follows is a statement of how to measure this correspondence between demonstrated degree of success and score in a test, or between the scores of the same persons in two or more different tests.
No measure of relationship between success in life and success in a test can be any more accurate than the original measures of success from which the calculation is made. ”

“ Out of the situation described above, which includes on the one hand the necessity for measurement as a means of testing the success of our theories and of our practice, and on the other hand of having objective standards, has grown the movement for measurement by means of standard tests and scales. A standard test which has been given to some thousands of children classified by grades or by ages, if given to another group of children of the same grade or age group will enable the teacher to compare the achievement of his children with that which is found elsewhere. ”

“ 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 associates, results of other mental tests, etc., are readily and with considerable reliability revealed in the individual's ability to perform this type of test. ”

“ The same individuals must be given both tests. (2) The number of individuals tested must be as great as 15 or 20, preferably more. (3) The individuals should be a fair sample of the population in regard to the abilities tested; they should not be so selected as to represent only a small part of the total range of ability. (4) The tests should be thorough enough to determine each individual's rank in each test, with a high degree of certainty. Sloppy testing gives a correlation nearer zero than it should be, because it "pies" the true orders to some extent. ”

“ Whatever it appears to be from mere inspection, it is a real measure of intelligence. Henceforth it stands or falls with the scale as a whole.
The reader will understand, of course, that no single test used alone will determine accurately the general level of intelligence. A great many tests are required; and for two reasons: (1) because intelligence has many aspects; and (2) in order to overcome the accidental influences of training or environment. If many tests are used no one of them need show more than a moderately high correlation with the scale as a whole. ”

“ The fact may be stated in this way:—the general efficiency of the test being granted, it is true to say that the large majority of those who pass an examination will be superior in efficiency to those who fail; but a few of those who fail may be superior to a few of those who pass. These errors are not peculiar to the examination system, they are inherent in all human judgments. It is necessary to allow for them in considering the failure of an individual candidate as an index of inefficiency. ”

“ Still more striking is the application of the intelligence test to the plain manual occupations. The worker fulfils, let us admit, his routine duty. But we have to ask, is this all that we have a right to demand from him? No. If the man is to be really competent, his mind ought to have a reach and an outlook which go beyond the mechanical operations of his job. I give an example:
Intelligence Test for Marine Engineers 1. ”

“ Only occasional attempts have been made to determine the influence of practice on the correlation of abilities, and those that have been reported have been based on so few practice trials that no review of them need be given. In the present chapter I shall present the results of an experiment in which a group of observers were repeatedly tested until in each test a practice limit was approximated, a limit which, in most cases, one hundred further trials failed to improve. The results have a real interest for vocational psychology. ”

“ Extending, as it commonly does, over many years of the individual's life, conducted by a considerable number and variety of examiners, and presented in a diversity of forms and methods, school work constitutes a type of mental test which is unequaled in its completeness. It is highly important for vocational psychology to ascertain the degree of correlation between the individual's record in the curriculum test and his success or fitness in later life. ”

“ On the record before us, neither the high school completion requirement nor the general intelligence test is shown to bear a demonstrable relationship to successful performance of the jobs for which it was used. ”

“ The results of this final sampling are turned over to experts who make a careful study of the results and of the answers to each question. This enables them to determine the relative value of each individual question and the selection that makes a proper balance.
If a trade test is good, a known expert, when tested, is able to answer all, or nearly all, the questions correctly; a journeyman is able to answer the majority; an apprentice a smaller part, and a novice practically none. ”

“ The name of every other competitor who has attained a general average of not less than 70 per cent; and all such applicants are hereby declared eligible to the class or place to test fitness for which the examination was held. ”

“ Considering the difficulty which normal adults sometimes have in distinguishing right and left, is it fair to use this test as a measure of intelligence? We may answer in the affirmative. It is fair because normal adults, notwithstanding momentary uncertainty, are invariably able to make the distinction, if not by direct association, then by an intermediate one. We overlook the momentary confusion and regard only the correctness of the response. Subjects who are below middle-grade imbecile, however long they have lived, seldom pass the test. ”

“ It may be necessary to make these tests over a period of years, and the tests themselves may and probably will require frequent revision and amendment as it is found in the course of their application that some of them are unnecessary and others inadequate. If it is found that any of the tests so applied is readily fulfilled by every subject examined, the effort is made to increase the difficulty of the test, until it has reached a stage where the perfect performance of all its requirements is barely within the reach of the ablest and most competent of all the engineers under examination. ”

“ It is extremely difficult to formulate mental tests so that they will equally well measure differences at each degree of ability. This objection should not hold, however, if the scoring were in units of time for the same task, as with the form board test. The essential characteristics of a test in order that it may indicate the form of a distribution is that the units of scoring shall be objectively equal under some reasonable interpretation and that they shall be fine enough to discriminate ability at each position on the scale. ”

“ Since an examination is, in effect, a form of psychological test, it is natural that psychologists should have attempted to introduce some of the technique of psychological testing into the work of examining students, in the interest of economy of the student's time as well as that of the examiner. The teacher prepares blanks which the student can quickly fill out if he knows the subject, not otherwise. ”

“ The judgments of various teachers and superintendents as to the inequalities of the units in any one test, and of the differences between the different editions of the same test, have proved the need of investigating these questions. Tests of adults in many lines of commercial work have yielded in many cases lower scores than those of the average eighth grade children. ”

“ It is not pretended that the test is a miniature of the work of such calling, nor that it is a fair sample of such work, nor even that it involves precisely the same mental functions that come into play in such work. The test records and ability in the particular type of work show high positive correlation, which means that an individual who is good or medium or poor in the one is, as a mere matter of fact, also found to be good, medium or poor in the other. ”

“ The correlation between a general intelligence test and a test for mechanical ability is considerably lower but still positive, coming to about +.4. Few if any real negative correlations are found between different abilities, but low positive or approximately zero correlations are frequent between different, rather special abilities. ”

“ Only 4 to 5 per cent. of the men in the Army made the score of A in the Alpha test, which means that they were able to answer in the given time, correctly, more than 135 of the 212 questions in the test. These were men of very superior intelligence—indeed, of marked intellectuality. Men of this mental type who had any leadership ability whatsoever made the various grades of commissioned officers. ”

“ Against this proposal it may be argued, that many illiterate men, although of great original genius, would be excluded if their competency were tried by such a test. My reply is, let them not be tried only by the ordinary rules of scientific books, but also by the general principles which the candidate professes, and let those principles be tested, to prove how far they are in accordance with sound philosophy. ”

“ Performance tests undergo much the same processes of sampling as do the oral and picture tests and they are calibrated in the same way. The principle followed here, as elsewhere, is that the value of a test 283lies not in its theoretical exactness but in its proved ability to pick out and classify correctly men of all degrees of skill within the trade. If the test does classify men in the groups in which they are known to belong, then it can be relied upon to classify correctly men about whom nothing is known in advance. ”

“ The instructions for the Performance Scale are given by means of gestures and demonstration, and a high score may be earned in it by an intelligent recruit who does not know a word of English.
All enlisted men are given either Alpha or Beta according to their degree of literacy. Those who fail in Alpha are given Beta, and those who fail to pass Test Beta are given an individual test. ”

“ The tests so far described, because they have to be given to each subject individually, require a great deal of time from the trained examiner, and tests are also needed which can be given to a whole group of people at once. For persons who can read printed directions, a group test can easily be conducted, though much preliminary labor is necessary in selecting and standardizing the questions used. ”

“ The real test of the student’s work is not to be found in what he did last night or in what he can show upon occasion as the result of a hasty cramming, but in what he has been doing through all the days and nights preceding the examination and in that net result which stands revealed in his mental grasp and effectiveness. Whether he becomes a man who will stand the hard tests the world puts upon every one who undertakes to do important work, will depend largely upon the habits he forms in the first year. ”

“ Intelligence tests of superior children. Intelligence tests as a basis for grading. Intelligence tests for vocational fitness. Other uses of intelligence tests. CHAPTER II
Sources of Error in Judging Intelligence 22
Are intelligence tests superfluous? The necessity of standards. The intelligence of retarded children usually overestimated. The intelligence of superior children usually underestimated. Other fallacies in the estimation of intelligence. Binet’s questionnaire on teachers’ methods of judging intelligence. Binet’s experiment on how teachers test intelligence. ”

“ The meaning of these results seems to be that before one attempts to interpret individual differences as disclosed by performance in such a series of simple tests, he should have clearly in mind the distinction between temporary proficiency and ultimate capacity. If he is interested, for example, in determining the vocational prospects of a youth, or the relative merits of candidates or culprits, it is important that he realize that relative abilities in many of these laboratory [Pg 262] tests may be changed quite beyond recognition by continued work. ”

“ They yield interesting results, when properly given, but are not without their faults. Sometimes a very superior subject fails, while occasionally an inferior subject unexpectedly succeeds. On the whole, however the test correlates fairly well with mental age. At the 14-year level less than 50 per cent pass; of “average adults,” from 60 to 75 per cent are successful. ”