ヒトにおける視覚刺激のエントロピー弁別

抄録

The present study examined college and graduate students’ discrimination learning of variability of visual stimulus sets. Each stimulus set consisted of 16 black and white icons. The variability of icons was manipulated across six levels by adjusting the number of identical and different icons in each set. Participants were trained to discriminate between high variability sets (with entropy values of 2.5, 3.0, and 3.5) and low variability sets (with entropy values of 0.5, 1.0, and 1.5). 15 out of 16 participants attained a learning criterion of 80% correct within four sessions. They also showed full transfer of the discrimination learning to test sets consisting of novel icons. During the test sessions, response rates and reaction times significantly varied across the different entropy values within the same response categories (high or low). The results show that the discrimination of stimulus sets of entropy values of 1.5 and 2.5 were relatively difficult for the participants and that humans can discriminate variability among visual stimuli indexed by entropy values. The implications of the present findings on comparative studies of same/different discrimination learning in human and nonhuman animals were discussed.