The measurement of intelligence: $b an explanation of and a complete guide for the use of the Standard revision and extension of the Binet-Simon intelligence scale

THE USES OF INTELLIGENCE TESTS

I

NTELLIGENCE TESTS OF RETARDED SCHOOL CHILDREN. Nu-

merous studies of the age-grade progress of school children have afforded

convincing evidence of the magnitude and seriousness of the retardation

problem. Statistics collected in hundreds of cities in the United States show

that between a third and a half of the school children fail to progress through

the grades at the expected rate; that from 10 to 15 per cent are retarded two

years or more; and that from 5 to 8 per cent are retarded at least three years.

More than10 per cent of the $400,000,000 annually expended in the United

States for school instruction is devoted to re-teaching children what they

have already been taught but have failed to learn.

The first efforts at reform which resulted from these findings were based on

the supposition that the evils which had been discovered could be remedied

by the individualizing of instruction, by improved methods of promotion,

by increased attention to children's health, and by other reforms in school

administration. Although reforms along these lines have been productive

of much good, they have nevertheless been in a measure disappointing. The

4 LEWIS M. (LEWIS MADISON) TERMAN

trouble was, they were too often based upon the assumption that under the

right conditions all children would be equally, or almost equally, capable of

making satisfactory school progress. Psychological studies of school children

by means of standardized intelligence tests have shown that this supposition

is not in accord with the facts. It has been found that children do not fall into

two well-defined groups, the "feeble-minded" and the "normal." Instead,

there are many grades of intelligence, ranging from idiocy on the one hand

to genius on the other. Among those classed as normal, vast individual dif-

ferences have been found to exist in original mental endowment, differences

which affect profoundly the capacity to profit from school instruction.

We are beginning to realize that the school must take into account, more

seriously than it has yet done, the existence and significance of these differ-

ences in endowment. Instead of wasting energy in the vain attempt to hold

mentally slow and defective children up to a level of progress which is nor-

mal to the average child, it will be wiser to take account of the inequalities

of children in original endowment and to differentiate the course of study

in such a way that each child will be allowed to progress at the rate which is

normal to him, whether that rate be rapid or slow.

While we cannot hold all children to the same standard of school progress,

we can at least prevent the kind of retardation which involves failure and

the repetition of a school grade. It is well enough recognized that children

do not enter with very much zest upon school work in which they have once

failed. Failure crushes self-confidence and destroys the spirit of work. It is a

sad fact that a large proportion of children in the schools are acquiring the

habit of failure. The remedy, of course, is to measure out the work for each

child in proportion to his mental ability.

Before an engineer constructs a railroad bridge or trestle, he studies the ma-

terials to be used, and learns by means of tests exactly the amount of strain

per unit of size his materials will be able to withstand. He does not work em-

pirically, and count up