抄録
Kindergarten children were trained on two consecutive intradimensional (ID), extradimensional (ED), and control shift problems after learning a discrimination problem. The relevant dimension was the same in ID shifts and was alternated from problem to problem in ED shifts. The stimulus dimensions in control shift problems were alternated from problem to problem. It was expected that dimensional, attending responses were assessed by the performances in ID and ED shifts and that non-dimensional, conceptual discrimination sets were by those in control shift. ID and control shifts became gradually easier from Original to Shift 2 problem, whereas the performances in ED shifts became worse from Original to Shift 1 and then better from Shift 1 to Shift 2. The difference between ID and ED shifts was significant only for Shift 1 problem. These results were explained in terms of relative effects of dimensional responses and nondimensional discrimination sets. It was suggested from the comparison with Shepp-Schrier's results by monkeys that the acquisition of discrimination sets is dependent upon developmental levels of the Ss.