Picture–word differences in decision latency: A test of common-coding assumptions

Three experiments examined the processing of pictures and words in two tasks of semantic decision--judgments of conceptual size and judgments of associative relatedness--in order to test the prediction from single-coding models of memory that different semantic decisions produce comparable picture-word latency differences. In Experiment 1 an interaction in decision latency was found such that picture-picture (P-P) pairs were significantly faster than word-word (W-W) pairs in decisions of size but not in decisions of associative relatedness. In Experiment 2 no latency differences were found in decisions of association for pairs presented in P-P, W-W, or mixed (P-W or W-P) forms. Decisions of size, however, were fastest for P-P pairs, intermediate for mixed pairs, and slowest for W-W pairs. In a third experiment, using a speeded inference task, the interaction obtained in the first two experiments was reproduced. In light of these results possible revisions to common-coding assumptions about the processing of pictures and words in semantic decisions are discussed.