Abstract
Identification of the second of two brief targets is impaired when inter-target lags are short (attentional blink, AB). The present study tested two explanations for the AB. Two streams of distractor digits were presented on either side of a fixation point. The number of distractors, and hence the lag, was manipulated between three letter targets. The targets appeared in either the left or right stream with equal probability. According to the resource-depletion hypothesis, longer lags provide more time for processing the leading target, thus releasing resources for the trailing target. If so, performance on the trailing targets would be impaired when the lag was short, irrespective of whether trailing targets appeared in the same or different streams. According to the temporary-loss-of-control (TLC) hypothesis, intervening distractors disrupt the current attentional set, producing a trailing-target deficit. Thus, the performance for the third target would be unimpaired if the immediately preceding target appeared in the same stream, because the preceding target produces the optimal attentional set for target identification. Such sparing should not occur when the preceding target appears in the other stream. Identification accuracy for trailing targets was unimpaired at Lag 1 (conventional Lag-1 sparing) and also at later lags, when preceded by another target in the same stream, supporting the TLC hypothesis but not the resource-depletion hypothesis. We concluded that the AB is caused by a disruption in attentional set when a distractor is presented while the central executive is busy processing the leading target.