Boolean map and object reconcile as the unit of visual working memory

Abstract

The unit of visual working memory is a fundamental issue under debate in the fields of cognitive psychology and neuroscience, with some traditional research suggesting that it is an object, while other recent studies demonstrating that a Boolean map offers a better account. The controversy surrounding the unit of visual working memory often centers on the representation of objects consist of same dimensional features (e.g. bicolor objects). For 2 colors in a bicolor object, some behavioral studies have suggested that they need to be represented by separate units, while some other studies using electrophysiological measures have found that they can be represented within a single unit. This apparent conflict hints that Boolean map and object may reconcile as the unit of visual working memory. Adopting the contralateral delay activity as an electrophysiological marker of visual working memory, experiments 1 and 2 consistently found that the contralateral delay activity amplitude for memorizing bicolor circles at P7/P8 conformed the Boolean map-based storage throughout the whole maintenance, while the contralateral delay activity amplitude at P3/P4 just conformed the object-based storage during the early period. It suggests though Boolean map got stronger supporting evidence than object, they 2 may coexist as the unit of visual working memory.