Attentional suppression is delayed for threatening distractors

According to the threat-capture hypothesis, fear-related stimuli have a high attentional priority. As a result, irrelevant-but-salient stimuli interfere more with a visual search task when they are perceived as threatening. We investigated the neural basis for behavioral interference in conditions that promote attentional suppression of distracting stimuli (i.e., easy search with fixed target/distractor roles). In Experiment 1, participants discriminated the shape of a neutral target (a flower), which competed for selection with a threat-related (spider) or neutral (leaf) distractor. In line with prior results, we observed larger interference from spider than leaf distractors. At an electrophysiological level, we found that participants actively suppressed both distractors as evidenced by the presence of a posterior positivity between 200-300 ms, the PD. Critically, the PD was delayed with spider compared to leaf distractors. Further, in the spider distractor condition, the offset of the PD component correlated with response time to complete the search task when the spider was present. Experiment 2 was a control experiment where we confirmed that the results depended on the execution of the peripheral search task. When participants performed a localization task on the fixation cross, the decisive results from Experiment 1 were not replicated despite equal peripheral stimulation. Our results indicate that the behavioral delay incurred by threatening stimuli is accompanied by a delay of suppressive mechanisms. In contrast, we found no evidence for initial capture followed by suppression that may be predicted by hypervigilance-avoidance theory.