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

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.