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.