Scattering Of Successes

It is sometimes a source of concern to the untrained examiner that the successes

and failures should be scattered over quite an extensive range of years. Why, it

may be asked, should not a child who has 10-year intelligence answer correctly all

the tests up to and including group X, and fail on all the tests beyond? There are

two reasons why such is almost never the case. In the first place, the

intelligence of an individual is rdinarily not even. There are many

different kinds of intelligence, and in some of these the subject is

better endowed than in others. A second reason lies in the fact that no

test can be purely and simply a test of native intelligence. Given a

certain degree of intelligence, accidents of experience and training

bring it about that this intelligence will work more successfully with

some kinds of material than with others. For both of these reasons there

results a scattering of successes and failures over three or four years.

The subject fails first in one or two tests of a group, then in two or

three tests of the following group, the number of failures increasing

until there are no successes at all. Success "tapers off" from

100 per cent to 0. Once in a great while a child fails on several of the

tests of a given year and succeeds with a majority of those in the next

higher year. This is only an extreme instance of uneven intelligence or

of specialized experience, and does not necessarily reflect upon the

reliability of the tests for children in general. The method of

calculation given above strikes a kind of average and gives the general

level of intelligence, which is essentially the thing we want to know.