Taking a bright view of negative priming in the light of dim stimuli: further evidence for memory confusion during episodic retrieval.

A same-different letter-matching task was used to examine the effects of stimulus intensity on negative priming, which is poorer performance when target letters have been presented as distractor letters on the immediately preceding trial. In Experiment 1, stimulus intensity was manipulated between-participants, whereas in Experiment 2, it varied randomly from trial-to-trial within-participants. In Experiment 1, negative priming was equivalent for both stimulus intensities. In Experiment 2, negative priming effects were larger for repeated intensity stimuli than for nonrepeated intensity stimuli, when stimulus intensity was dim. Furthermore, for repeated intensity stimuli, negative priming effects were enhanced when the overt response required to the stimulus was repeated from prime to probe trial. These results are consistent with the hypothesis that negative priming may be due to memory confusion, rather than to inhibition of the distractor stimuli.