Abstract
Salient, task-irrelevant stimuli that consistently appear with the same defining feature (e.g., a specific color) can be actively downweighted by the visual system. This attentional suppression mechanism has been shown to benefit visual search: Search targets are more efficiently located in displays with a salient color singleton distractor than in displays without a distractor. The singleton presence benefit has been commonly attributed to reduced allocation of attention to the location of the distractor. We question here whether suppression merely excludes locations for attentional selection, or whether the suppressive mechanism fundamentally alters the representation of other elements in the scene. To examine this question, we assessed the effects of suppression on nearby elements by perceptually grouping sets of elements together in the search array. On different trials, the search target either appeared in the same perceptual group as a to-be-suppressed color singleton distractor, at an equidistant location but in a different group, or at a more distant location in a different group. Experiment 1 showed that selection of the target was enhanced when it was grouped with a suppressed distractor. Experiment 2 varied the locations grouped together from trial to trial, and also demonstrated a same-group benefit. To test whether participants strategically prioritized the group containing the salient distractor (because it had fewer potential target elements), Experiment 3 changed the number of elements in each group. Target selection was enhanced when grouped with the distractor even when the distractor-containing group had more items to search. Consistent with the effects of grouping, a benefit of closer target-distractor distance was also observed in the experiments. Together the results reveal the novel finding that attentional suppression facilitates selection of stimuli near the distractor, implying that distractor downweighting may be achieved by biasing the competition for representation in favor of surrounding locations.