Feature Integration in Visual Working Memory

Abstract

This article reviews studies on feature integration in visual working memory, which is critical for various cognitive activities using visual information. Studies involving change detection and multiple object tracking tasks reported that feature-integrated object representations are successfully maintained, and that the parietal cortex plays a major role. Subsequent studies that involved explicit tasks on feature combination, such as feature swap detection and multiple object permanence tracking, revealed the role of the prefrontal cortex, but it remains equivocal whether visual working memory holds feature-integrated object representations. In addition, recent studies using an implicit-association test measure, the redundant feature reviewing task, combining object reviewing and redundancy gain paradigms, provided evidence on feature-integrated object representations in visual working memory. Electroencephalography data analysis showed prefrontal activities reflecting the integration of the color and shape of an object, which is consistent with the result of studies measuring explicit tasks. Altogether, these findings are consistent with a recently proposed "feature confirmation" model, claiming that object features can be integrated in bottom-up visual processing and the limitation in feature binding occurs in the top-down mechanism which confirms the presence of features and their combination.