The problem was to determine the levels of intellectual capacity necessary at various ages for acquiring rapid and efficient nonspatial discrimination learning sets on problems of increasing complexity.

This study investigated the possible differential effects of a series of soluble discrimination problems on internal versus external locus of control subjects. It was hypothesized that externals exposed to a series of discrimination problems would perform better on a test task than external controls, while internals exposed to the same problems would not perform better on the test task relative to their controls. As anticipated, the internals were not affected by the discrimination problems. However, contrary to expectations, the externals were not facilitated by exposure to the soluble problems. Since many external subjects failed to solve all of the soluble problems, a facilitative effect may depend upon the problems being solved.