Abstract
We previously reported that when observers voluntarily directed their attention to one of two overlapping outline triangles, they reported that the subsequent afterimage of the attended triangle was weaker than that of the unattended triangle (Psychonomics, 2000). We extended this result by using RSVP tasks to control the allocation of attention. Attention was directed at either the inducer triangle or a central digit stream (Exp. 1), or at either the inducer triangle or an overlapped brightness-balanced non-inducer circle that did not produce afterimages (Exp. 2). Occurrences of a target color or digit were counted. The afterimage of the attended inducer triangle was delayed in onset relative to when the triangle was ignored. Finally, in order to examine the attention effects using a criterion-independent measure, we adapted a dot-integration paradigm so that a gap in a circular array of discs could be found only when complete afterimages were visible. On each trial 6 of 12 locations on a circle were randomly chosen to contain inducer discs that rapidly changed colors, as did a single central ring. Observers either counted the number of times all inducer discs became the same color (to ensure attention to all discs) or counted the number of times that the central ring turned yellow. Following adaptation, test discs that were not perceptibly different than the afterimage discs briefly appeared in 5 of the 6 remaining locations, followed by a mask. Observers reported the location of the missing disc. Gap detection accuracy was reduced 33% when the inducer discs were attended relative to when they were ignored. Across experiments, the fact that attention during adaptation weakened or delayed afterimages suggests that selective attention primarily facilitates the adaptation of polarity-independent processes that modulate the visibility of afterimages rather than facilitating the adaptation of polarity-selective processes that mediate the formation of afterimages