Schedule of Events | Symposia

Testing the duration of spontaneous spatial representation in working memory when items can be differentiated by temporal-order

Poster Session A - Saturday, March 29, 2025, 3:00 – 5:00 pm EDT, Back Bay Ballroom/Republic Ballroom

Sage Bendickson¹ (sbendic1@gmail.com), Nicholas Schmitz¹, David Sutterer¹; ¹University of Tennessee Knoxville

Space and time are proposed to play a critical role in working memory formation and maintenance relative to other object features. Prior work shows that alpha-band EEG activity spontaneously carries information about an object’s location when location is task-irrelevant (Foster et al., 2017). Recent work finds that observers make microsaccades towards an objects encoded hemifield during the maintenance of non-spatial features when responses are tested by ordinal position (de Vries et al., 2023), suggesting that space maintains its prioritized role at a hemifield specific level when temporal information can be used for individuation. However, an open question is whether objects’ precise locations are maintained throughout a memory delay when ordinal individuation is possible. To answer this question, we used a sequential two-item delayed color estimation task in which each stimulus presentation was followed by a 1-second delay. Observers were cued to report the color of one of the two circles based on its ordinal position (first or second). This ensured that the objects could be individuated without relying on location. We applied an Inverted Encoding Model to the topography of EEG alpha-band power to measure the spatial representation of each item in the sequence. We found a robust representation of each item’s location during the delay immediately following encoding, and the spatial representation of item one did not sustain following the presentation of the second item. Thus, our results indicate that spatial locations are spontaneously maintained after initial encoding but can be discarded after new information is presented.

Topic Area: ATTENTION: Spatial