Visual sameness: a choice time analysis of pattern recognition processes.

Ss judged the "sameness" of pairs of matrixes, each having several cells blackened at random. One group (Similarity search) classified matrix pairs as "same" if they had even one pair of blackened cells in corresponding locations. A second group (Identity search) classified pairs as "same" that were identical with respect to all blackened cell locations. Decision times of the Similarity-search group were much longer than those of the Identity-search group. While the performance of the Similarity-search Ss indicated they were engaged in a serial processing of the stimulus array that of the Identity-search Ss in some conditions closely approximated gestalt processing.