Abstract
The Attentional Blink (Raymond , Shapiro, & Arnell 1992) is a well known example of the limited capacity of visual encoding. Recently, the phenomenon of sparing has been demonstrated to occur for four or more targets in a row (Nieuwenstein & Potter 2006; Olivers, Van Der Stigchel & Hulleman 2005; Kawahara, Kumada & DiLollo in Press), effectively eliminating the blink for targets presented at lags 2 and 3. This finding places traditional limited capacity accounts in a difficult position.
Our modeling work, suggesting the use of types and tokens as a working memory substrate, broadens the notion of capacity to include not just the identity, but also the episodic distinctiveness of targets. Our simulations suggest that sparing of target identity occurs because the system is incapable of disengaging attention from an unbroken sequence of targets. When this occurs, multiple items are encoded into a single perceptual episode, resulting in a loss of the episodic distinctiveness of individual items. This loss of episodic information predicts a number of impairments that are verified in behavioral experiments that will be described. These effects include (a) loss of temporal order of targets, (b) increased binding errors for elements of complex targets and (c) repetition blindness for identical items within a sequence of spared items.
EPSRC grant GR/S15075/01, NIMH MH47432