Early Perceptual Locus of Suppression During the Attentional Blink

The attentional blink (AB) demonstrates that recognizing the second of two targets (T1 and T2) is difficult when they appear in close succession in a rapid serial visual presentation (RSVP) stream. The AB has been widely accepted as a suppression of T2 processing at the postperceptual stage. The current event-related potential study updates this view by demonstrating the existence of an early perceptual locus of suppression during the AB. Using line drawings of real-life objects as RSVP items, we required participants in Experiment 1 to either discriminate the exact identities or simply classify the object categories of T1 and T2, and in Experiment 2, we instructed participants to discriminate either T1 and T2 identities (dual-target task) or only T2 identity (single-target task) to invalidate the temporal expectation as an alternative account. The results of Experiments 1 and 2 showed that the T2-elicited first positive peak (P1) component was consistently decreased at Lag 3 whenever a dual-target, but not single-target, task was required, and the magnitude of this P1 suppression was significantly predictive of the behavioral AB magnitude in each dual-target task. When the RSVP items were substituted by classic but size-matched alphanumeric characters in Experiment 3, no P1 suppression was evident as expected, ruling out the large stimulus size as an alternative interpretation. These findings provide the strongest evidence to date that the AB can begin to suppress T2 processing at a very early perceptual stage, at least when observers encounter RSVP items of real-life objects, which calls for more flexible cognitive models for the AB.