Time courses of the negative and positive repetition effects.

Time courses of the negative repetition effect (NRE), a poorer detection of the target in noise-same-as-target than in noise-alternative-target displays, and its opposite, the positive repetition effect (PRE), were examined. Experiment 1 showed that displays in which a low-contrast target was present with a high-contrast noise produced a larger NRE than did displays in which a contrast relationship between items was reversed. A negative contrast repetition effect (NCRE) was also found that was comparable to the NRE. Experiment 2 showed that dimensional Korean letters (e.g., [symbol: see text]) whose configural differences were apparent in orientation produced the largest PRE at a 0-ms stimulus onset asynchrony, whereas featural Korean letters (e.g., [symbol: see text]) that differed in the number of elements yielded the largest NRE when a noise letter preceded a target letter by 50 ms. Experiments 3A and 3B indicated that the NCRE may arise from spatial attention.