Same–different discrepancy in an exhaustive matching task

Abstract

In this study, we investigated in a multistimulus matching task the size of the discrepancy between response times for “same” and response times for “different” judgments. Frequently, results have shown that “same” judgments are faster than “different” judgments. Krueger (1984) found inversion in the speed advantage when stimuli were presented simultaneously and concluded that a self-termination factor would explain this result. In the experiment reported here, the subject had to exhaustively scan the whole set of items in the stimulus string. The analysis shows no significant interaction of presentation and response type; that is, the advantage for same stimuli is not reduced for simultaneous over subsequent presentation of pairs. Neither the method of presentation nor the type of stimulus reversed the advantage of “same” judgments; however, the discrepancy between response times for “same” and “different” judgments increased with increases in set size when the number of common elements between presentation and test sets were greater.