A revised blocked-trial procedure for establishing arbitrary matching in children.

The present study evaluated a modified blocked-trial procedure in the learning of arbitrary matching tasks (A1-B1, A2-B2) by children. The procedure consisted of five steps. In Step 1, the comparisons (B1 and B2) were presented simultaneously with the samples (A1 and A2). The comparisons were presented at fixed locations (B1 left and B2 right), and the samples, A1 and A2, were randomly presented in successive trials. Subjects were reinforced for placing A1 on B1 and A2 on B2. Step 2 was the same except that the locations of B1 and B2 were reversed. Step 3 was the same as Steps 1 and 2 but with reversed B1-B2 locations after every fourth trial. Step 4 was the same as Step 3 except that the B1-B2 locations randomly changed over trials. Step 5 was the same as Step 4 except that subjects were required to point to the B stimuli. The procedure was highly effective--far more so than the traditional blocked-trial procedure.