Arousal does not enhance the dominant spatial scope of attention

A fundamental aspect of attention is its spatial scope: whether attention is narrowly focused or more broadly distributed across the visual field. Here, we examined whether the spatial scope of attention is modulated by tonic arousal level. Based on findings that arousal amplifies the selectivity of attention and memory, we hypothesized that arousal would enhance the currently dominant spatial scope of attention (narrow or broad). Participants (N = 39) performed a visual search task designed to measure the breadth of attention. Auditory white noise was presented in half of the blocks to increase tonic arousal. Each trial started with a procedure that aimed to induce a narrow or broad breadth of attention. Pupil size measurements and visual search task performance revealed that the manipulations of arousal and breadth of attention were successful. However, we found strong Bayesian evidence against an effect of arousal on attentional scope. We discuss the implications of this finding for arousal-biased competition theory.