Spatially guided distractor suppression during visual search

Abstract

AbstractPast work has demonstrated that active suppression of salient distractors is a critical part of visual selection. Evidence for goal-driven suppression includes below-baseline visual encoding at the position of salient distractors (Gaspelin and Luck, 2015) and neural signals such as the Pd that track the position and number of distractors in the visual field (Feldmann-Wustefeld and Vogel, 2019). One basic question regarding distractor suppression is whether it is inherently spatial or nonspatial in character. Indeed, past work has shown that distractors evoke both spatial (Theeuwes, 1992) and nonspatial forms of interference (Folk and Remington, 1998), motivating a direct examination of whether space is integral to goal-driven distractor suppression. Here, we provide clear evidence for a spatial gradient of suppression surrounding salient singleton distractors. Replicating past work, both reaction time and neural indices of target selection improved monotonically as the distance between target and distractor increased. Importantly, these target selection effects were paralleled by a monotonic decline in the amplitude of the Pd, an electrophysiological index of distractor suppression. Moreover, multivariate analyses revealed spatially selective activity in the theta band that tracked the position of the target and – critically – revealed suppressed activity at spatial channels centered on distractor positions. Thus, goal-driven selection of relevant over irrelevant information benefits from a spatial gradient of suppression surrounding salient distractors.