Categorically Defined Targets Trigger Spatiotemporal Attention

Transient attention to a visually salient cue enhances processing of a subsequent target in the same spatial location between 50 to 150 ms after cue onset (Nakayama & Mackeben, 1989). Do stimuli from a categorically defined target set, such as letters or digits, also generate transient attention? Participants reported digit targets among keyboard symbols in a changing array of 8 items. When one target preceded a second target in the same location at an SOA of 107 ms (but not 213 ms), the second target was reported more often than in a condition in which there was no leading target. When the two targets were at different locations, report of the second target was impaired. With both letters and digits as targets, the enhancement effect was shown not to be due to category priming. Critically, the attentional benefit was present whether or not participants reported the leading target. Transient attention, contingent attentional capture, popout, and lag 1 sparing in the attentional blink may involve a common mechanism for directing processing resources towards salient and task relevant stimuli.