Attentional control and capture in the attentional blink paradigm: Evidence from human electrophysiology

Abstract

We studied attentional control mechanisms using electrophysiological methods, focusing on the N2pc event-related potential (ERP), to track the moment-by-moment deployment of visual spatial attention. Two digits (T₁ and T₂, both red or both green, and masked, were embedded in a rapid serial visual presentation of letter distractors with an SOA of 200 ms or 800 ms. T₁ was at fixation, whereas T₂ was 3° to the left or right of fixation and presented with a concurrent equiluminant distractor digit in a different colour. T₁ and T₂ were reported in one block of trials, and only T₂ in another block (order counterbalanced). Accuracy for T₂ was lower at short SOA than at long SOA when both T1 and T2 were reported, suggesting an attentional blink (AB) effect. It was difficult to ignore T₁ because T₁ had the same colour as T₂, producing a large deficit in T₂ accuracy at short SOA in the control condition. The amplitude of the N2pc ERP component was attenuated in the short-SOA condition relative to the long-SOA condition, both in the experimental and the control conditions, suggesting that T₁ involuntarily captured visual spatial attention and that while attention was deployed on T₁, the processing of T₂ was significantly impaired.