Effects of similar information in the search task on visual working memory representation.

Visual working memory (VWM) plays a crucial role in receiving essential information and filtering out interference in the midst of an abundance of information. During the VWM maintenance phase, the VWM representations are affected by similar (to the memory content) information. The sensory-recruitment hypothesis attributes this to the overlap in cortical areas between the VWM representation and the perceptual stimulus representation. In addition, the storage and maintenance of VWM and the processing of external visual stimuli may compete for the same attention resources. Similar information impacts existing VWM representations through integration and replacement; however, the regulatory effects of attentional resources on these processes remain poorly understood. This study used a dual-task paradigm in which participants were required to complete an additional search task during the maintenance phase of a working memory task. Under difficulty control, Experiment 1 examined how similarity and attentional engagement modulate integration and substitution. Experiment 2 employed peripheral cues to dissociate attentional demands between these mechanisms, while Experiment 3 further validated differential sensitivity by manipulating search difficulty to control attention resource allocation. Results demonstrate that integration is regulated by both similarity and attentional resources, whereas replacement is solely governed by similarity. Crucially, integration requires attentional engagement as a requisite premise, while replacement operates without such necessity.