Visual Working Memory Organizes Functional Related Objects beyond the Spatiotemporal Limit

Abstract

Functional relations can be directly “seen” and used to organize perceptual representations, but interactive positions are prerequisites for such perceptual grouping. The current study examined whether visual working memory (VWM) could automatically take advantage of functional relations in a more flexible way. In three experiments, participants were required to memorize a set of objects while ignoring the underlying relations between them. Results showed that although functional grouping was task-irrelevant, functional relations between objects could be extracted and used to enhance memory performance. More interestingly, functionally related objects could be grouped in the working memory phase even when they were not spatial interactive (Experiment 2). It was different from the perceptual grouping effect (Experiment 1) and reveals a unique memory grouping mode. Moreover, such functional grouping could still happen when object pairs entered VWM sequentially (Experiment 3), suggesting an active modification according to functional relations inside VWM. These findings suggest that VWM representations can be automatically structured through functional grouping, and grouping takes place in a flexible manner that can break the spatiotemporal constraints of perception.