Attentional guidance from two representations of the same or different dimensions in visual working memory

Previous studies have only focused on the interference effect induced by multiple task-irrelevant representations from the same dimensions in visual working memory (VWM). The present study reexamined the issue by not only focusing on interference effect but also facilitation effect induced by multiple task-irrelevant representations from the same dimension in VWM. Furthermore, the guidance effect of multiple task-irrelevant representations from different dimensions in VWM was also investigated. Participants were instructed to complete a gap-location search task while holding two items in VWM. In Experiment 1, one of the colors (match-1) or both colors in VWM (match-2) matched with one or two targets or distractors in the search array. No guidance effects were found for match-1 trials, but there was a reliable interference effect when both colors in VWM were presented as distractors and a facilitation effect when they matched the color of two search targets. Experiment 2 was carried out to examine the guidance effect produced by multiple task-irrelevant representations from different dimensions in VWM. Participants were required to memorize the color and direction of an arrow. Attentional guidance effects were found when each one of the VWM features matched the search target, but there was no additive facilitation effect when both features were validated in visual search. These results provide evidence that multiple items in VWM can guide the attention simultaneously, but the guidance effects are flexible and various across different types of stimuli.