Other Uses Of Intelligence Tests
Another important use of intelligence tests is in the study of the factors
which influence mental development. It is desirable that we should be able
to guard the child against influences which affect mental development unfavorably;
but as long as these influences have not been sifted, weighed, and measured, we have
nothing but conjecture on which to base our efforts in this direction.
When we search the literature
of child hygiene for reliable evidence as
to the injurious effects upon mental ability of malnutrition, decayed
teeth, obstructed breathing, reduced sleep, bad ventilation,
insufficient exercise, etc., we are met by endless assertion painfully
unsupported by demonstrated fact. We have, indeed, very little exact
knowledge regarding the mental effects of any of the factors just
mentioned. When standardized mental tests have come into more general
use, such influences will be easy to detect wherever they are really
Again, the most important question of heredity is that regarding the
inheritance of intelligence; but this is a problem which cannot be
attacked at all without some accurate means of identifying the thing
which is the object of study. Without the use of scales for measuring
intelligence we can give no better answer as to the essential difference
between a genius and a fool than is to be found in legend and fiction.
Applying this to school children, it means that without such tests we
cannot know to what extent a child's mental performances are determined
by environment and to what extent by heredity. Is the place of the
so-called lower classes in the social and industrial scale the result of
their inferior native endowment, or is their apparent inferiority merely
a result of their inferior home and school training? Is genius more
common among children of the educated classes than among the children of
the ignorant and poor? Are the inferior races really inferior, or are
they merely unfortunate in their lack of opportunity to learn?
Only intelligence tests can answer these questions and grade the raw
material with which education works. Without them we can never
distinguish the results of our educational efforts with a given child
from the influence of the child's original endowment. Such tests would
have told us, for example, whether the much-discussed "wonder children,"
such as the Sidis and Wiener boys and the Stoner girl, owe their
precocious intellectual prowess to superior training (as their parents
believe) or to superior native ability. The supposed effects upon mental
development of new methods of mind training, which are exploited so
confidently from time to time (e.g., the Montessori method and the
various systems of sensory and motor training for the feeble-minded),
will have to be checked up by the same kind of scientific measurement.
In all these fields intelligence tests are certain to play an
ever-increasing role. With the exception of moral character there
is nothing as significant for a child's future as his grade of
intelligence. Even health itself is likely to have less influence in
determining success in life. Although strength and swiftness have always
had great survival value among the lower animals, these characteristics
have long since lost their supremacy in man's struggle for existence.
For us the rule of brawn has been broken, and intelligence has become
the decisive factor in success. Schools, railroads, factories, and the
largest commercial concerns may be successfully managed by persons who
are physically weak or even sickly. One who has intelligence constantly
measures opportunities against his own strength or weakness and adjusts
himself to conditions by following those leads which promise most toward
the realization of his individual possibilities.
All classes of intellects, the weakest as well as the strongest, will
profit by the application of their talents to tasks which are consonant
with their ability. When we have learned the lessons which intelligence
tests have to teach, we shall no longer blame mentally defective workmen
for their industrial inefficiency, punish weak-minded children because
of their inability to learn, or imprison and hang mentally defective
criminals because they lacked the intelligence to appreciate the
ordinary codes of social conduct.