The object as the unit of interaction between visual working memory and visual attention

This study aimed to determine the unit of interaction between visual working memory (VWM) and attention by examining two opposing hypotheses: (a) the unit of interaction is a Boolean map, 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). In Experiments 1 and 2, participants held in their VWM one color, or multiple colors (two or three) that either came from one integrated object or separate objects, and then performed a visual search task that sometimes contained a distractor with a memory-matching color. Results showed that the VWM-driven attentional-capture effect triggered by colors from an integrated object was larger than that from separate objects. Moreover, surprisingly, the magnitude of the attentional guidance effect of multiple color representations from the integrated object was almost equivalent to that of a single-color object. Experiment 3 replicated the modulation effect of objecthood and demonstrated that it was not driven by different memory fidelity. Experiments 4 and 5 extended these findings by generalizing the effect to two features from different dimensions (i.e., color and orientation), and from different modules (i.e., visual and verbal color representations). These results suggest the objecthood of multiple representations could modulate their ability to guide attention, supporting the object-unit hypothesis. These findings have crucial implications for understanding the architecture of interactions between VWM and attention.