The Measurement of Intelligence | Page 5

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
materials 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 empirically, and count upon patching up the mistakes which
may later appear under the stress of actual use. The educational
engineer should emulate this example. Tests and forethought must take
the place of failure and patchwork. Our efforts have been too long
directed by "trial and error." It is time to leave off guessing and to
acquire a scientific knowledge of the material with which we have to
deal. When instruction must be repeated, it means that the school, as
well as the pupil, has failed.
Every child who fails in his school work or is in danger of failing
should be given a mental examination. The examination takes less than
one hour, and the result will contribute more to a real understanding of
the case than anything else that could be done. It is necessary to
determine whether a given child is unsuccessful in school because of
poor native ability, or because of poor instruction, lack of interest, or
some other removable cause.
It is not sufficient to establish any number of special classes, if they are
to be made the dumping-ground for all kinds of troublesome cases--the

feeble-minded, the physically defective, the merely backward, the
truants, the incorrigibles, etc. Without scientific diagnosis and
classification of these children the educational work of the special class
must blunder along in the dark. In such diagnosis and classification our
main reliance must always be in mental tests, properly used and
properly interpreted.
INTELLIGENCE TESTS OF THE FEEBLE-MINDED. Thus far
intelligence tests have found their chief application in the identification
and grading of the feeble-minded. Their value for this purpose is
twofold. In the first place, it is necessary to ascertain the degree of
defect before it is possible to decide intelligently upon either the
content or the method of instruction suited to the training of the
backward child. In the second place, intelligence tests are rapidly
extending our conception of "feeble-mindedness" to include milder
degrees of defect than have generally been associated with this term.
The earlier methods of diagnosis caused a majority of the higher grade
defectives to be overlooked. Previous to the development of
psychological methods the low-grade moron was about as high a type
of defective as most physicians or even psychologists were able to
identify as feeble-minded.
Wherever intelligence tests have been made in any considerable
number in the schools, they have shown that not far from 2 per cent of
the children enrolled have a grade of intelligence which, however long
they live, will never develop beyond the level which is normal to the
average child of 11 or 12 years. The large majority of these belong to
the moron grade; that is, their mental development will stop somewhere
between the 7-year and 12-year level of intelligence, more often
between 9 and 12.
The more we learn about such children, the clearer it becomes that they
must be looked upon as real defectives. They may be able to drag along
to the fourth, fifth, or sixth grades, but even by the age of
16 or 18 years they are never able to cope successfully with the more
abstract and difficult parts of the common-school course of study. They
may master a certain amount of rote learning, such as that involved in

reading and in the manipulation of number combinations but they
cannot be taught to meet new conditions effectively or to think, reason,
and judge as normal persons do.
It is safe to predict that in the near future intelligence tests will bring
tens of thousands of these high-grade defectives under the surveillance
and protection of society. This will ultimately result in curtailing the
reproduction of feeble-mindedness and in the elimination of an
enormous amount of crime, pauperism, and industrial inefficiency. It is
hardly necessary to emphasize that the high-grade cases, of the type
now so frequently overlooked, are precisely the ones whose
guardianship it is most important for the State to assume.
INTELLIGENCE TESTS OF DELINQUENTS. One of the most
important facts brought to light by the use of intelligence tests is the
frequent association of delinquency and mental deficiency. Although it
has long been recognized that the proportion of feeble-mindedness
among offenders is rather large, the real amount has, until recently,
been underestimated even by the most competent students of