Where we perceive before we look: The distribution of presaccadic attention assessed with dynamic 1/f noise

Abstract

Already before the onset of a saccadic eye movement, we preferentially process visual information at the upcoming eye fixation. This presaccadic shift of attention is typically assessed via localized test items, which potentially bias the attention measurement. Here we show how presaccadic attention shapes perception from saccade origin to target when no scene-structuring items are presented. Participants made saccades into a 1/f ("pink") noise field, in which we embedded a brief orientation signal at various locations shortly before saccade onset. Local orientation discrimination performance served as a proxy for the allocation of attention. Results demonstrate that (1) saccades are preceded by shifts of attention to their goal location even if they are directed into an unstructured visual field, but the spread of attention, compared to target-directed saccades, is broad; (2) the presaccadic attention shift is accompanied by considerable attentional costs at the presaccadic eye fixation; (3) objects markedly shape the distribution of presaccadic attention - demonstrating the relevance of an item-free approach for measuring attentional dynamics across the visual field.