Abstract
When two masked targets are presented in rapid succession, correct identification of the first (T1) leads to impaired identification of the second (T2). Behavioral and electrophysiological studies have demonstrated that during this ‘attentional blink’ (AB), T2 is processed to a semantic level even though discrimination accuracy is impaired. The purpose of the present work was to test whether electrophysiological indices of semantic processing during the AB are modulated by the manipulation of T1 task difficulty. Eight participants performed a T1 task that involved indicating the direction of a central arrow that was flanked by arrows pointing in the same direction (easy) or in a different direction (hard). The T2 task involved indicating whether a word presented either 300 ms or 700 ms after T1 was related or unrelated to a context word presented at the very beginning of the trial. Each subjects' electroencephalogram was recorded using 32 electrodes and the event-related potential time-locked to the T2 word was extracted. Consistent with previous studies, during the 300–500 ms after the T2 word there was a larger negative response to unrelated words than to unrelated words. Unlike previous studies, however, the size of this negativity changed as a function of the interval between T1 and T2 in the difficult target task. The present results constrain current models of the attentional blink such that although semantic processing can occur during the attentional blink, it is not obligatory and depends on task difficulty.
This research is supported by NIMH R03 MH070638