Abstract
The current study aimed to answer a fundamental question regarding two central components of our cognitive system: what is the unit of the interaction between visual working memory (VWM) and visual attention. To address this crucial issue, we proposed two opposing hypotheses: (a) the unit of interaction is a Boolean map, which is a data format that can contain only one within-dimension feature (e.g., “red” or “circle”; Boolean-map-unit hypothesis); and (b) the unit of interaction is an object (object-unit hypothesis). We tested these two distinct hypotheses by adopting the memory-driven attentional capture effect as well as manipulating the perceptual organization (objecthood) of two memorized color representations. In two experiments, participants held two colors in VWM from either one or two objects, or one color, and then performed a search task that sometimes contained a singleton-distractor with a memory-matching color. Experiment 1 assessed whether attentional capture would be influenced by the objecthood of multiple representations in VWM. The results showed that two colors in VWM could simultaneously guide attention when encoded from an integrated object, but did not when they came from two separate objects. Experiment 2 replicated the results of Experiment 1 and generalized to two different colors with essentially similar physical formats (i.e., e.g., two different colored semicircles). More importantly, the results showed that the attentional capture by two different colors encoded from one integrated object was equivalent to that of a single color. These results suggested that the objecthood of multiple VWM representations significantly influences their ability for attentional guidance, thus supporting the object-unit hypothesis. These novel findings provided first evidence indicating that the interaction between VWM and attention was implemented at the level of object and have crucial implications for understanding the architecture of interaction between VWM and attention.