In a color-singleton search task, observers located an odd-colored target (e.g., a green diamond among red diamonds) and reported which side (left or right) was "chipped"; color repetition effects were thus examined independently of response priming. In randomly intermixed "adaptation" trials, all stimuli were the same color (e.g., all green) and observers made no response. Search (e.g., for a red target among green distractors) was faster (by about 90 ms) when only the distractor color was viewed in the preceding adaptation trial (e.g., all green diamonds) relative to when only the target color was viewed (e.g., all red diamonds), suggesting that color-singleton search is facilitated by adaptation to the distractor color. To understand what type of color representation was being adapted, adaptation trials were manipulated while search trials remained the same. This phenomenon is not due simply to adaptation to the distractor color per se because the effect disappeared when same-colored diamonds were replaced by a large color patch (with 11 times greater total area). However, it persisted when the diamonds were reduced in area by nearly 90% (to appear like colored dots), suggesting that this color adaptation is not energy dependent, but does require the presence of multiple colored items. By varying the number of adapting diamonds, we found that robust adaptation effects occurred so long as there were 2 or more adapting diamonds. Additional experiments showed that the effect was not specific to eccentricity or shape, and that the adaptation occurs rapidly (within 30 ms exposure). These results, taken together, suggest that distractor-color adaptation occurs where color representation is fairly independent of image attributes (color energy, position, eccentricity, shape, and size), but this adaptation does require that more than one colored item is presented. The role of target-distractor assignment in distractor-color adaptation will be discussed.
ASJC Scopus subject areas
- Sensory Systems