Working memory’s pointer system is governed by physical objecthood, not spatiotemporal information

To properly reflect the dynamic environment, the online representations in visual working memory (VWM) must be constantly accessed and modified when the corresponding items change. Such updating depends on a continuous mapping between each VWM representation and a subset of the external environment, instantiated by a "pointer system." If this mapping is disrupted, the representations cannot be updated, and instead VWM removes the unmapped representations and starts anew. During this "resetting" process, people are blind to salient changes in the items whose representations are inaccessible, creating a behavioral cost. The goal of this study was to test whether VWM's pointers are governed by spatiotemporal information or objecthood. In two preregistered studies, participants performed an "online change detection" task, reporting visible changes in items' shapes, which happened during their (task-irrelevant) movement. Experiment 1 showed that when an intact object abruptly changes its spatiotemporal trajectory, the mapping is sustained, with no resetting cost. Experiment 2 showed that when only half the object changes its trajectory, which effectively splits the object in two, the mapping no longer survives, with diminished performance indicating a resetting process. Critically, a behavioral cost was found even for the half that continued in the same spatiotemporal trajectory, pinpointing objecthood as the driving factor. Together, the results demonstrate that resetting does not reflect mere pointer reassignment, but a specific invalidation of the mapping between representations and the environment. In sustaining this mapping, VWM's pointer system relies not on spatiotemporal information per se, but on physical objecthood.