Abstract
Exogenous, or involuntary, attention refers to the automatic orienting response to a location where a salient cue has occurred. Many studies have demonstrated that perceptual processing is improved at validly cued locations (cue and target at the same location) relative to invalidly cued locations (cue and target at different locations), with seemingly little influence of visual field location (Henderson & Macquistan, 1993). However, other research on endogenous attention has demonstrated differences in attentional performance within vs. across hemifields (e.g., Alvarez & Cavanagh, 2005; Strong & Alvarez, 2020), suggesting that there are independent attentional resources in each visual hemisphere. To test whether similar constraints are present during exogenous attention we assessed the spatial distribution of exogenous attention in a visual cueing paradigm. Participants (N = 49) performed a task discriminating the tilt of a masked Gabor patch target presented randomly at one of four locations evenly distributed around a central fixation point. Shortly prior to the onset of the target, a spatially non-predictive salient visual cue (a white circle outlining the location) appeared randomly at one of the four possible target locations, thus yielding four possible cueing conditions: validly cued, invalid same-hemifield, invalid different-hemifield, and invalid diagonal. Analysis on visual discrimination accuracy showed reliable differences among the cueing conditions (p< 0.015) with highest performance for the validly cued locations. Interestingly, we observed a smaller cueing benefit when comparing valid vs. within-hemifield-invalid relative to valid vs. across-hemifield-invalid, possibly suggesting that the spatial distribution of exogenous attention is constrained by the architecture of the visual system.