UBC Theses and Dissertations
Focal distraction : spatial shifts of attention are not required for contingent capture Zuvic, Samantha Marija
Contingent capture occurs when distractors that share distinguishing characteristics with a target capture attention and slow down target identification. Conventionally, this slowdown has been attributed to the time wasted by an inappropriate attentional shift to the location of a distractor. To examine this account, we obviated the spatial shift by presenting distractors at fixation, and measured contingent capture both directly by measuring response times and indirectly by estimating the duration for which the target remains vulnerable to backward masking. Contingent capture invariably occurred when a salient distractor was presented within about 600 ms before the target. Because spatial shifts were ruled out using our procedure, the conventional account is insufficient. We augment that account with a two-stage model in which stimuli must pass an input filter tuned to the target's distinguishing characteristic before gaining access to a high-level stage which is unavailable for targets while distractors are being processed.
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