Visual Search Within Working Memory

Attention and working memory are 2 key pillars of cognition. Despite much research, there are important aspects about the relationship between the 2 constructs that are not well understood. Here we explore the similarity in the mechanisms that select and update working memory to those that guide attention during perception, such as in visual search. We use a memory search task where participants memorize a display of objects on a grid. During memory maintenance, participants are instructed to update the spatial positions of a subset of objects. The speed of the updating process should reflect the accessibility of the to-be-updated subset. Using this task, we explored whether landmark findings in visual search would hold true for memory search. In Experiment 1, we found a search asymmetry-it was easier to access memory representations defined by a feature than defined by the lack of a feature. In Experiment 2, we found target-distractor similarity effects-updating a single target was easier when the distractors were farther away in feature space. In Experiment 3, we found a feature versus conjunction benefit-access times were much faster for instructions to move objects defined by only 1 feature (e.g., all triangles) as opposed to a conjunction of features (e.g., all red triangles). In Experiment 4, we find a set-size effect-update times increased with the number of items in memory, particularly for conjunctive stimuli. Taken together, our results suggest a common coding and selection scheme for working memory and perceptual representations.