Effect of stimulus repetition on positive and negative identity priming.

Most negative-priming experiments have used a limited number of stimuli that are repeated many times throughout the experiment. We report five experiments that examine in greater detail the role of stimulus repetition in negative priming. Subjects were presented with displays consisting of two or more words, and were required to name the word printed in red. On attended repetition (AR) trials, the target word was the same as the target word on the preceding trial. On ignored repetition (IR) trials, the target word was the same as the distractor word on the preceding trial. Experiments 1 and 2 used novel words, and obtained positive priming on AR trials, but no negative priming on IR trials. Experiments 3 and 4 used repeated words, and obtained negative priming on IR trials, but no positive priming on AR trials. In Experiment 5, both novel and repeated words were intermixed, and negative priming was observed for repeated, but not novel, IR conditions, whereas positive priming was observed for novel, but not repeated, AR conditions. Together, Experiments 1-5 demonstrate that positive and negative identity priming are modulated by stimulus repetition and are stimulus specific.