e requirements reasonably
well, a fact which bears eloquent testimony to the keen psychological
insight of their author.

[13] See p. 55.

In arranging the tests into a system Binet's guiding principle was to
find an arrangement of the tests which would cause an average child of
any given age to test "at age"; that is, the average 5-year-old must
show a mental age of 5 years, the average 8-year-old a mental age of
8 years, etc. In order to secure this result Binet found that his data
seemed to require the location of an individual test in that year where
it was passed by about two thirds to three fourths of unselected
children.

It was in the assembling of the tests that the most serious faults of
the scale had their origin. Further investigation has shown that a great
many of the tests were misplaced as much as one year, and several of
them two years. On the whole, the scale as Binet left it was decidedly
too easy in the lower ranges, and too difficult in the upper. As a
result, the average child of 5 years was caused to test at not far from
6 years, the average child of 12 years not far from 11. In the Stanford
revision an effort has been made to correct this fault, along with
certain other generally recognized imperfections.

SOME AVOWED LIMITATIONS OF THE BINET TESTS. The Binet tests have often
been criticized for their unfitness to perform certain services which in
reality they were never meant to render. This is unfair. We cannot make
a just evaluation of the scale without bearing in mind its avowed
limitations.

For example, the scale does not pretend to measure the entire mentality
of the subject, but only _general intelligence_. There is no pretense of
testing the emotions or the will beyond the extent to which these
naturally display themselves in the tests of intelligence. The scale was
not designed as a tool for the analysis of those emotional or volitional
aberrations which are concerned in such mental disorders as hysteria,
insanity, etc. These conditions do not present a progressive reduction
of intelligence to the infantile level, and in most of them other
factors besides intelligence play an important role. Moreover, even in
the normal individual the fruitfulness of intelligence, the direction in
which it shall be applied, and its methods of work are to a certain
extent determined by the extraneous factors of emotion and volition.

It should, nevertheless, be pointed out that defects of intellige