keen sensory discrimination.
Feeble-minded children, unless of very low grade, do not differ very
markedly from normal children in sensitivity of the skin, visual
acuity, simple reaction time, type of imagery, etc. But in power of
comprehension, abstraction, and ability to direct thought, in the nature
of the associative processes, in amount of information possessed, and in
spontaneity of attention, they differ enormously.

3. _Binet would test "general intelligence."_ Finally, Binet's success
was largely due to his abandonment of the older "faculty psychology"
which, far from being defunct, had really given direction to most of the
earlier work with mental tests. Where others had attempted to measure
memory attention, sense discrimination, etc., as separate faculties or
functions, Binet undertook to ascertain the _general level_ of
intelligence. Others had thought the task easier of accomplishment by
measuring each division or aspect of intelligence separately, and
summating the results. Binet, too, began in this way, and it was only
after years of experimentation by the usual methods that he finally
broke away from them and undertook, so to speak, to triangulate the
height of his tower without first getting the dimensions of the
individual stones which made it up.

The assumption that it is easier to measure a part, or one aspect, of
intelligence than all of it, is fallacious in that the parts are not
separate parts and cannot be separated by any refinement of experiment.
They are interwoven and intertwined. Each ramifies everywhere and
appears in all other functions. The analogy of the stones of the tower
does not really apply. Memory, for example, cannot be tested separately
from attention, or sense-discrimination separately from the associative
processes. After many vain attempts to disentangle the various
intellective functions, Binet decided to test their combined functional
capacity without any pretense of measuring the exact contribution
of each to the total product. It is hardly too much to say that
intelligence tests have been successful just to the extent to which they
have been guided by this aim.

Memory, attention, imagination, etc., are terms of "structural
psychology." Binet's psychology is dynamic. He conceives intelligence as
the sum total of those thought processes which consist in mental
adaptation. This adaptation is not explicable in terms of the old mental
"faculties." No one of these can expl