Abstract
Observers can suppress salient-but-irrelevant distractors when searching for a pre-specified visual target. We hypothesize that this salient-signal suppression process is shaped proactively by the observer's attentional set and is largely dependent on the current availability of top-down attentional control. Here, we asked how a temporal disruption of attention control would affect this ability to suppress salient-but-irrelevant distractors during visual search. In order to manipulate attentional control, we used an attentional blink paradigm in which the first target (T1) was a number within an RSVP stream of letters and the second target (T2) appeared within a visual search array that also contained a salient distractor. We examined ERPs elicited by various configurations of the T2 search array at lag 2 (within the attentional blink) and lag 8 (outside of the attentional blink) to independently track selective processing of target and distractor. During the attentional blink, an ERP component associated with target selection (the N2pc) was delayed by ~35 ms. In contrast, an ERP component associated with distractor suppression (the distractor positivity; PD) was absent entirely. These results suggest that if the search array appears while the system is busy processing T1, (i) search for T2 is put on hold until after processing of T1 is complete; (ii) distractor suppression is not possible. On this basis, we conclude that the salient-signal suppression indexed by the PD is highly vulnerable to disruptions of attentional control.
Meeting abstract presented at VSS 2017