Emotional Distractors Capture Attention even at Very Low Contrast Levels: ERP evidence

Emotional visual stimuli, whether appealing or aversive, preferentially capture exogenous attention due to their evolutionary significance. This study assessed whether such capacity persists at low contrast levels, where stimuli are minimally perceived. To this end, we recorded behavioral and electrophysiological (event-related potentials, ERPs) indices of attentional capture from 38 participants who were exposed to negative, neutral, and positive scenes, each presented at four distinct contrast levels. These contrast levels had previously resulted in a correct recognition rate of up to 25%, 50%, 75%, and 100% in a previous sample of 235 participants. Participants were presented with these scenes as distractors while simultaneously performing a perceptual task involving line orientation discrimination. The ERP results confirmed the expected emotional effect on exogenous attention and, critically, unveiled its persistence across all contrast levels. Specifically, occipito-parietal P1 (88-119 ms) was larger for negative than for positive distractors, while in a spreaded N2 component, positive distractors elicited larger amplitudes relative to both negative (213-354 ms) and neutral (213-525 ms) images. These findings reinforce the advantage of emotional distractors in accessing neural processing automatically and highlight the existence of a temporal negativity bias. Importantly, our novel findings emphasize the robustness of this exogenous attention pattern, present even under limited perceptual conditions.