Sage Bendickson¹, Nicholas Schmitz, Ilke Kavusturan, Alexis McCraw, David Sutterer; ¹University of Tennessee Knoxville

Space and time are thought to play a priority role in working memory (WM) formation and maintenance, due to their role in feature binding and tendency for incidental encoding in memory. However, the extent that space and time operate complementarily or trade priority depending on task relevance remains an open question. Here we investigated if the relevance of spatial information changes the deployment of spatial attention, and its contribution to task-specific memory maintenance, when items are separated in space and time. We report two experiments that differed in whether location or color was the tested feature. In both experiments, we measured EEG alpha-band power while observers memorized the target feature of two sequentially presented colored dots. We then applied an inverted encoding model (IEM) to the topography of oscillatory alpha-band power (8 – 12 Hz) on the scalp to measure how long the location of each item was attended. In Experiment 1, observers performed a delayed color estimation task, and we found that patterns of alpha-band power only tracked the location of the most recently presented item. In Experiment 2, observers performed a delayed spatial estimation task, and we found that patterns of alpha-band power tracked each item’s location and that the spatial representation of item 1 persisted significantly longer than in Experiment 1. Together, our results show that spatial attention only maintains the most recent item’s location in a location-irrelevant task, but that multiple sequential locations are actively attended when location is the tested feature.