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.