Hypotheses,strategies, and stereotypes in discrimination learning

In the course of two experimentss groups of kindergarten, second, fourth, sixth grade and college students received several discrimination problems. Each trial with feedback was followed by a series of blank trials, which served as a probe for S's hypothesis. Ss responded systematically during the blank trials on about 90% of the probes. Beginning at the second grade they typically showed characteristic hypothesis-testing behavior, viz., keeping confirmed hypotheses, rejecting those disconfirmed, etc.