Golnaz Forouzandehfar¹ (gforouz@vols.utk.edu), Ilke Kavusturan¹, A. Caglar Tas¹; ¹The University of Tennessee-Knoxville

Previous work suggests competing accounts of how attention interacts with the contents of visual working memory (VWM). Tas et al. (2016) showed that executing a saccade to an irrelevant secondary object (SO) during the retention interval impaired VWM, whereas covertly attending to the SO produced no interference, indicating a dissociation between overt and covert shifts of attention. In contrast, Hamblin-Frohman and Becker (2019) argued that this interference only arises when attention selects an object’s features, suggesting feature-based attention (FBA), rather than saccades themselves, drives VWM costs. To distinguish these possibilities, we similarly asked participants to complete either an FBA or a spatial attention (SA) task during the retention interval of a change-detection task. In separate blocks, participants either executed a saccade to the SO (overt attention) or remained fixated throughout the trial (covert attention). Using the same FBA (reporting an arrow direction) and SA (reporting a dot location) tasks as in Hamblin-Frohman and Becker (2019), Experiment 1 replicated their results for covert attention: FBA task significantly decreased VWM performance compared to baseline (where no SO was presented). However, in overt attention blocks, both tasks similarly impaired performance compared to baseline, suggesting that the apparent selectivity of FBA interference can be explained by differences in task demands under fixation, but saccade execution introduces an additional decrement beyond these costs. Experiment 2 modified FBA task (reporting SO identity: triangle or square) to ensure equivalent difficulty as SA task. Both tasks impaired VWM performance relative to baseline. Crucially, this impairment was larger for overt than covert attention. Together, these findings indicate the disruptions created by the covert attention tasks are most likely due to increased dual-task demands. However, overt shifts of attention produce a separate source of disruption, most likely due to saccade targets being automatically encoded into VWM to aid visual stability.