CHAPTER V

DIFFERENT TYPES OF MENTAL TESTS

The character of any mental test or series of tests is determined primarily, of course, by the purpose for which the test is applied, and, secondarily, by the known or obvious mental limitations of the individual under examination.

Mental tests thus classify themselves, in the first instance, into as many different classes as there are specific purposes to be served by their use, particular kinds or classes of mental ability and capacity to be ascertained, or degrees of previously known mental limitations. Each one of these classifications cuts across all other classifications at some point, so that it is, as a matter of practice, impossible to tabulate or catalogue mental tests in such a way as to separate them into sharply defined or permanently detached groups or classes.

Broadly, all mental tests subdivide at first into tests devised for use with persons of normal mental capacity and development and tests for intelligences that are not fully developed. This is, perhaps, the chief permanent and fixed classification of intelligence tests that can be made, for in a group of tests for the sub-normal mind would be included the entire series of tests adapted for the examination of the mental powers of children of all ages, from earliest infancy to maturity. In fact, the standard method of rating or grading adults of undeveloped or sub-normal intelligence is to classify them by their mental age as compared with the performance of normal children of the same age.

Thus, a man or woman of twenty-five who is able to make a high score in tests which are passed successfully by normal children of eight, but who fails when subjected to tests which a normal child of ten should pass easily, is rated approximately as of mental age nine.

Cutting across this classification is the arbitrary classification of tests adopted in the psychological work of the United States Army, in which every officer and enlisted man is classified as to his relative intelligence by means of scientific mental tests. The Army tests are of three principal kinds. There is a series of tests, known as the Alpha, designed to measure the intelligence of individuals who can read and write the English language. For those who are either illiterate or whose ability to read or write is confined to some language other than English, there is the Beta series of tests. These may register as high a degree of intelligence as the Alpha tests; the results are merely not expressed in terms of the English language. The third classification in the Army is the individual tests, applied to those who fail to make a satisfactory score under either the Alpha or the Beta tests. This is, in its Army application, a system of tests for the sub-normal adult intelligence. Thus the broad classification first set forth above, in substance actually holds in the classification of the Army tests.

Under each of these two broad classifications, and particularly under the first (since in general, every-day practice it is of little service to undertake to analyze minutely the capacities and limitations of the sub-normal mind except in the application of these tests to growing children) there are many possible subdivisions of mental tests, based upon the particular mental qualities which it is desired to measure.

First and most useful generally are general intelligence tests, which must usually be subdivided into a series of related tests. Then, for varying purposes, such as the examination of candidates for particular classes of employment requiring special ability or capacity, there may be applied speed tests, accuracy tests, perception tests, coördination tests, memory tests, mathematical tests, and a wide variety of others. These are tests which primarily measure the subject’s ability to perform certain specific acts under pre-determined conditions, the determination of capacity in excess of that actually demonstrated under test depending upon the facility and accuracy with which the subject responds to the conditions of these tests. Of course, every scientific mental test is based upon the performance of certain acts, since it is only through action of some sort, whether by speech, writing, or the performance of a manual operation, that any one is able to express his mental ability at any time.

But while it is relatively a simple matter to devise tests that satisfactorily indicate the subject’s possession of the more obvious mental powers indicated by such tests as those last listed above, there is another class of mental tests, designed primarily to indicate or determine the possession of the more abstract qualities, the manifestation of which through the individual’s simple and ordinary actions is less obvious to the untrained observer. This is the class of tests that are designed to measure the degree in which an individual possesses such qualities as moral sense, form perception, the power to reason from cause to effect, poetic discrimination, ability to understand complicated instructions, judgment, sense of the right relationship of things and ideas. It is as important, if one is to arrive at a true measure of any individual’s mental capacity, that he be tested as to his possession of these more or less abstract qualities, as it is to determine his possession of concrete abilities. In other words, the normal mind of an intelligent adult is capable of dealing intelligently with ideas and abstractions. The mentality that does not respond with a certain degree of readiness to ideal conceptions is to that extent sub-normal. The only possible way of determining the possession of unusual or super-normal mental capacity is by means of the demonstration that its possessor grasps readily and responds unhesitatingly to the presentation of abstract concepts.

The demonstration itself must, of course, be concrete. Unless the individual possessing extraordinary mental power is able, as Kipling phrases it, to

. . . . press the logic of a fact To its ultimate conclusion in unmitigated act.

it is of no social consequence whatever that he may possess the mental catholicity of a Shakespeare. There is no place in the modern world for “mute, inglorious Miltons.”

Indeed, it may be questioned whether a “mute, inglorious Milton” ever existed. The world is full of people who regard themselves as “unappreciated.” Everyone is familiar with the unfortunate type that is forever seeking sympathy, constantly on the lookout for friendly shoulders on which to sob out the sad tale of the world’s harshness. Under psychological tests the preponderant majority of this type of individual is clearly demonstrated to be mentally deficient or sub-normal in some important respect. The occasional individual of normal mental capacity who fails to demonstrate that capacity by the performance of specific acts is merely mentally lazy. In other words, it may be set forth as a sound conclusion, capable of scientific proof, that mental capacity in the healthy, normal individual always finds means of expressing itself in concrete and socially useful ways, whenever its possessor actually desires so to utilize his mental powers.

In the devising and preparation of tests intended to measure the less obvious of the mental powers, a considerable degree of ingenuity and the greatest amount of scientific care and technical skill is required. To the person untrained in psychology tests designed to measure the possession of the more abstract powers frequently look childish, if not positively silly. Since it is essential, in the case of Army officers and men, to determine as nearly as it may be done by simple and easily applied tests their possession of a wide variety of mental qualities, some of the elements of the Army Alpha test appear to the concrete type of mind to be futile, if not absurd. But any comprehensive system of mental tests must include, as there have been included in the Mentimeter tests presented in this volume, a considerable proportion which do not on their face appear to be directed toward the disclosure of the ordinary and useful mental capacities. It is of vital importance, if the results of any given series are to give an adequate picture of the actual abilities and possibilities of the subject examined, that tests of this character be included among them.

Each of the possible classes of mental tests may be set to any one of an infinite number of standards. General intelligence tests, for example, may be set to the standard of the average university graduate, so that the result when applied to any individual gives a fair estimate of the subject’s intelligence as compared with that of those who have demonstrated the possession of mental capacity sufficient to complete satisfactorily a university course. Or the standard may be that of the average lawyer, the average high school pupil, the average normal child of any age or school grade, the average skilled mechanic, the average labourer, or the average child below the age of speech. And, in practice, what is measured is, after all, general intelligence.

Intelligence, as has been frequently pointed out, while it does not depend upon the individual’s ability to read and write, is so generally accompanied by the definite and intimate knowledge of the symbols which we call letters, words, and figures, and of their meaning, that in the great majority of cases in which it is desired to apply the test of intelligence this can best be done, or at least most readily be done, by the use of these familiar symbols; in other words, by tests which involve only the acts of reading and writing. If intelligence may be defined as the intellectual power of adaptation to environment, a complete test of intelligence determines the individual’s ability to recognize the situation in which he finds himself, perceive his own relation to the situation, analyze it, and arrive at a conclusion as to what he should do next; then put that conclusion into effect by means of a concrete act. Thus one may learn a great deal about an individual’s mental capacity by observing his conduct when he misses a train. But since it is not practicable to apply this method of inquiry in every case, the next best thing is to ask the question, “What would you do if you missed your train?” To ask this question of a subject is next best to seeing him in such a situation. He must exercise his sense of reality upon it, size it up and plan his reaction.

Since all life is made up of situations in which the individual places or finds himself and from which he must extricate himself, and since the broader the mental capacity, the more easily will the individual meet situations as they arise, the ideal mental test is one that presents a situation such as does or might occur in real life, and requires the subject to extricate himself, or at least to indicate his first and immediate impulse toward action should such a situation arise.

Since the purpose of mental tests is primarily to determine intelligence rather than the possession of physical qualities, it is conceivable that, in many situations, properly devised questions may give a fairer view of the subject’s mental capacity than would observation of the same individual in action in a real situation. Thus a person of the highest intelligence and mental capacity might be deficient in physical courage, so that if we could observe him in action on unexpectedly meeting a highway robber armed with a revolver we might be able to deduce from his actions absolutely no criteria upon which to form a sound judgment as to his mental powers; the same subject, asked the question, “What would you do if held up by a footpad?” might exhibit in his answer unusual ability to perceive quickly and reason soundly to an intelligent conclusion—in other words, to demonstrate his possession of considerable mental capacity.

All properly constructed mental tests are, therefore, in effect, attempts to reproduce or project upon a laboratory scale situations such as the subject is or may be called upon to meet in actual life. It is obvious that ability to analyze quickly and propound immediately the correct course of action when the situation presented is unusual and outside the range of every-day experience indicates clearly the possession of mental ability greater than is required to meet only ordinary and familiar situations. The theory of the mental test as a reproduction in miniature of actual situations is thus commented on by Daniel W. La Rue:

“It is useless to ask a savage what he would do if he missed his train, or an old bachelor what he would do when the baby cried, or a green soldier how he will behave when a shell bursts near him. Further, just which of many millions of situations are so important, or so typical, or so closely correlated with a web of others, similar or dissimilar, that they should be admitted among the select few that form a test? The answer is coming as a slow deposit from the stream of experience and experiment.”

Doctor La Rue, pursuing the same theme, points out with sound philosophy the necessity for grading mental tests to fit the apparent or previously known mental level of the subject.

“We must beware how we use a high-level test to measure low-level intelligence. If our scales are set to weigh nothing less than a hundred pounds or upward, we cannot tell accurately the weight of an eighty-pound man. In particular, since devisers of tests are usually expert in the use of literary symbols, and since ordinary test conditions limit seriously the possible variety of responses open to the subject, we slide easily into the belief that a dextrous manipulation of symbols is the prime display of intelligence. No doubt it is true that in an ideally developed brain the language centres (tracts) are well webbed up with every other trait-tract. Ideally, to experience anything is to be able to utter it. But the stammering lover is matched by the stammering thinker, and there certainly may be intelligent action without the power to put it adequately into words. Probably Cæsar is the only great general who could describe a battle as finely as he could plan it or fight it. Words without deeds, deeds without words: we must be prepared for both. Our old test question, ‘Why should we judge a person by what he does rather than by what he says?’ applies to the test itself.”

Because of the fact that there is a percentage of persons who, either through unfamiliarity with the English language or lack of skill in expressing themselves through word and number symbols, do not respond to tests based on the use of words, any comprehensive scheme of mental tests must contain a proportion of tests the response to which may be made without the use of written, printed, or spoken words. Of such a nature were the Army Beta tests, already referred to, and there will be found in the Mentimeter tests presented in this volume a considerable number of forms that fall into this class of tests. To the person accustomed to dealing chiefly with words and ideas, it is not always readily apparent that proof of a high degree of intelligence can be obtained by means of tests which do not employ these familiar symbols. As a matter of practical fact, however, results which check up very closely with every other means of determining the subject’s intelligence were quite uniformly obtained through the use of the Beta tests in the Army, and similar success has been achieved through the application of tests of the same general character in industry and education.

There is another general class of tests to which only passing reference need be made here. This is the class of trade tests, in which by a combination of oral examination and specific performance the precise ability or degree of skill of the subject in a given occupation or trade is determined. Although frequently confused with psychological tests, this class of tests does not properly come within the scope of mental tests in the sense of being chiefly measurements of intelligence. It has been found, however, in practice that the individual’s native intelligence or inherent mental capacity has, in most occupations, a very decided bearing upon the degree of skill which he or she can attain, even in the simpler mechanical operations. Because of this fact, as well as because the value of trade tests in industry is of increasing importance, some of the principles underlying the construction of trade tests and their application are discussed briefly in a later chapter.