Delineating resetting and updating in visual working memory based on the object-to-representation correspondence

Abstract

When an object we represent in visual working memory (VWM) changes, its representation is modified accordingly. VWM can either access and change the existing representation by an updating process, or it can reset, by encoding the object in its novel status as a new representation. Our goal was to show that the determining factor of updating versus resetting is the availability of a stable correspondence between the object and its VWM representation. Here, we demonstrate that updating relies on the object-to-representation mapping to access and modify the appropriate representation, while losing this mapping triggers a resetting process. We compared very similar situations of object separation that either allowed the mapping to hold, or caused it to be lost. When an object that was mapped to one representation separated, VWM reset, manifested by a sharp drop in the contralateral delay activity (CDA) amplitude (an electrophysiological marker of VWM contents; Experiment 1), and a behavioral cost to detect salient changes that co-occurred with the resetting-triggering event (Experiment 2). When each part was mapped to a different representation, the separation resulted in updating, with a gradual rise in CDA amplitude (Experiment 1), and a reduced behavioral cost (Experiment 2). Thus, while updating and resetting resulted in similar final representations (corresponding to the post-change objects), their dynamics were different, depending on the availability of the mapping. Our results reveal the triggering conditions of resetting and updating, establish methods to study these online processes, and highlight the importance of the object-to-representation correspondence in VWM.