The effects of eccentricity on attentional capture

Abstract

Visual attention may be captured by an irrelevant yet salient distractor, thereby slowing search for a relevant target. This phenomenon has been widely studied using the additional singleton paradigm in which search items are typically all presented at one and the same eccentricity. Yet, differences in eccentricity may well bias the competition between target and distractor. Here we investigate how attentional capture is affected by the relative eccentricities of a target and a distractor. Participants searched for a shape-defined target in a grid of homogeneous nontargets of the same color. On 75% of trials, one of the nontarget items was replaced by a salient color-defined distractor. Crucially, target and distractor eccentricities were independently manipulated across three levels of eccentricity (i.e., near, middle, and far). Replicating previous work, we show that the presence of a distractor slows down search. Interestingly, capture as measured by manual reaction times was not affected by target and distractor eccentricity, whereas capture as measured by the eyes was: items close to fixation were more likely to be selected than items presented further away. Furthermore, the effects of target and distractor eccentricity were largely additive, suggesting that the competition between saliency- and relevance-driven selection was modulated by an independent eccentricity-based spatial component. Implications of the dissociation between manual and oculomotor responses are also discussed.

Sparse spatial scaffolding for visual working memory

“…Our results are complementary to a large body of work on the role of eccentricity in vision (e.g., [41][42][43][44][45] that is concerned, for example, with the change in resolution when moving from central to peripheral vision. Our task was not designed to tap into such differences.…”

“…Though our star]ng point was different, our experimental manipula]ons resemble those in complementary research on the role of eccentricity and crowding in vision (e.g., [66][67][68][69][70][71][72][73][74] ) and visual working memory (e.g., [75][76][77] ). This literature has typically focused on other ques]ons, such as how visual resolu]on changes when moving from central to peripheral vision.…”