Distractors sharing critical target features summon, but do not engage, attention: An EEG study ☆.

Abstract

The mechanisms involved in handling task-irrelevant distractors remain a topic of debate. This study investigated how spatial and feature-based attentional templates influence distractor handling. Participants searched for a target located in a known region while ignoring the distractor region. The distractor either shared the features of the target, or differed by dimension, or varied by modality. Behaviorally, distractors that matched the target features caused the most interference, more so than those differing in dimension or modality. EEG results revealed that N2pc amplitudes increased for lateral distractors, particularly when distractors shared features with the target. Cross-modal distractors elicited a distinct central contralateral negativity (CCN), but did not impair search performance. Both the CCN and positive posterior contralateral (Ppc) components indicated early sensory registration of lateralized distractors, ruling out the Ppc as a marker of early distractor suppression. These findings support the 'down-weighting' hypothesis, showing that distractors can be registered without further attentional engagement. N2pc findings also suggest that the spatial template acted through "distractor location shielding" rather than "target location enhancement". Our results suggest that effective distractor handling via distractor-location shielding and feature/dimension-based down-weighting may render proactive or reactive suppression mechanisms, typically reflected by the P_D (Distractor Positivity) component, unnecessary.