Abstract
We use working memory (WM) to temporarily keep information in mind. When interrupted, decrements in WM performance are often observed. However, how task-irrelevant interruption affects WM and attention is not fully understood. Here, we use two different online measures of activity to more finely delineate how task-irrelevant interruption affects WM representations. We use lateralized alpha (8-12 Hz) power as an index of sustained spatial attention (Thut et al., 2006) and Contralateral Delay Activity (CDA) as an index of the number of items in WM (Vogel & Machizawa, 2004). In Experiment 1 (n=20), participants performed lateral change detection. We used four colored squares as interrupters, which appeared on the midline on 25% of trials. Following interruption, lateralized WM representations, as indexed by the CDA, sustained for several hundred milliseconds. On the other hand, attention, as indexed by lateralized alpha power, immediately became non-lateralized for several hundred milliseconds before re-lateralizing as participants began reorienting attention towards the attended hemi-field. In Experiment 2 (n=20), we were interested in whether top-down control modulates the impacts of interruption on performance by manipulating the probability (25% vs. 75%) of an interruption across blocks. Participants knew an interruption was more or less probable in each block. When there was a higher probability of interruption, participants reoriented their attention more quickly to the attended side and maintained lateralized WM representations for longer following interruption. The lateralized alpha suppression and CDA results from both experiments indicate that attention and WM are distinct mechanisms that work hand-in-hand to protect internally maintained representations. Additionally, top-down control is able to influence both of these mechanisms in an effort to revive and maintain internal representations following an interruption.
Meeting abstract presented at VSS 2018