Abstract
Traditionally, theoretical accounts of the attentional blink (AB) have postulated that the deficit occurs due to limited attentional resources being devoted to the first target (T1) at the expense of the second (T2; e.g., Chun & Potter, 1995). Recent theories have challenged this model (e.g., Di Lollo et al., 2005; Olivers et al., 2007), proposing instead that the AB occurs because subjects fail to maintain appropriate levels of attentional control when presented with distractors. Accordingly, it has been shown that there is no T1 and T3 performance difference (no AB) when three targets from the same attentional set are presented sequentially in an RSVP stream (Uniform trials). However, Dux et al. (2008) have argued that this finding rather reflects a performance trade-off between T1 and T3. In support of their hypothesis, Dux et al. (2008) found an AB (T1[[gt]]T3 performance) under three-target Uniform conditions when subjects increased the resources they exogenously allocated to T1. Here, we investigated whether an endogenous manipulation of the attentional resources subjects devote to targets also effects the AB. Subjects viewed RSVP streams where three letter targets appeared sequentially amongst digit distractors. The attentional resources devoted to the targets were manipulated by varying each target's relevance to the task. In T1-relevant blocks, T1 required report on all trials whereas T2 and T3 required report on only 50% of the trials (subjects were instructed at the end of each trial whether to report just T1 or all three targets). Conversely, in T3-relevant blocks, T3 required report on all trials and T1 and T2 on only 50% of the trials. T1 performance was superior to T3 performance in T1-relevant blocks (an AB), and T3 performance was greater than T1-performance in T3-relevant blocks (a reversed AB!). These findings provide strong support for resource depletion accounts of the AB.
This research was supported by an NIMH (R01 MH70776) grant to R.M.