Abstract
Sustained spatial attention allows us to selectively process visual information through prioritization of specific spatial locations. Here, we investigated the impact of task-irrelevant interruption on sustained spatial attention during maintenance. Previous work has suggested that even when reaction times are increased due to interruptions, spatial attention does not obligatorily shift to the position of those interruptions (Folk & Remington, 1998). Instead, they proposed that responses are slowed because the interruptions interfered with target processing, even though attention did not shift to the location of the interruptions (e.g., Becker, 2007). Previously, we found that irrelevant interruption onsets can disrupt EEG activity that tracks ongoing storage in visual working memory (VWM). Here, we examined whether those onsets also capture spatial attention precisely at the interruption’s location, even when interruptions appeared well after attention was focused on the target locations. We used EEG to track covert attention while subjects stored information in VWM, either with or without the onset of an irrelevant interruption during the delay period. We tracked the moment-to-moment locus of covert spatial attention by applying an inverted spatial encoding model to the scalp topography of alpha-band (8-12 Hz) activity. Participants performed a color change detection task during which they remembered the color and location of one or two circles over a 1,500 ms delay. On 50% of trials, a task-irrelevant circle appeared 700 ms after the onset of the memoranda. When interruptions were not presented, alpha topography tracked the target locations throughout the delay. When an irrelevant interruption was presented, by contrast, the spatial representation of the target dissipated following interruption onset, and alpha-band activity subsequently began to track the location of the irrelevant interruption. Thus, spatial attention shifts in a sustained fashion towards the location of irrelevant interruption, even well after attention has been focused on distinct target locations.