This study investigated the reason for a shift in laterality during short-term learning. The new criterion of reversed association, developed by Dunn and Kirsner (1988), was adopted to determine whether different information processing mechanisms mediate between the before and after phases of learning. A random shape recognition task (Test1) was conducted first, followed by a paired-association learning task. Several days later, the same subjects retook the same recognition task (Test 2). The results showed (1) a shift in laterality through the learning experience occurred between Tests, and (2) the different information processing mechanisms mediated between Tests, and (3) the left hemisphere seemed to exert metacontrol in Test 2.