Effects of Exogenous Attention and Target Eccentricity on Visual Sensitivity

Abstract

Based on findings about the modulation of Receptive Fields (RFs) due to exogenous covert attention, we investigated the costs and benefits of exogenous covert attention, compared to a neutral condition, at different distances from central fixation (4 or 14° eccentricity) on visual sensitivity. We used a 2x3 design and measured visual sensitivity by participant ability to correctly distinguish the orientation of Gabor patches of different contrast levels, when targets appeared at either cued, neutral or uncued locations, and at 4 or 14° eccentricity from fixation. In experiment 1, we found that our neutral cue (a square) enhanced visual sensitivity to a similar extent as a single informative cue at both 4 and 14° eccentricity. In experiment 2, a low-contrast neutral central fixation cue was used, and was found to have similar effect on visual sensitivity as an uninformative cue at 4° eccentricity, and a similar albeit non-significant pattern was found at the 14° eccentricity. The effects of the properties of neutral cues are discussed, considering implications for the use of such cues in future studies, as well as in relation the effects of such cues on attentional resources across the visual field.