Abstract
Observers are able to use an attentional template consisting of one, or even two, colors to guide the eyes to matching objects in a search array. We tested whether an exclusionary attentional template could be used to guide eye movements away from, and thus exclude from search, known irrelevant items. Eye movements were recorded during a visual search task in which observers searched for a Landolt-C target in a 16-item array. The array items were divided into four each of four different colors. A cue at the beginning of each trial indicated which color(s) were and were not relevant for search. When the cue depicted a color that would not be the target color, observers' first few eye movements were nevertheless directed to items that matched that color. This capture effect was plausibly driven by the maintenance of the to-be-excluded color in visual working memory (VWM). To test this hypothesis, a condition was included in which the to-be-excluded color was cued indirectly by displaying the three colors that could be the target item color. This latter cue conveyed precisely the same information but could be implemented by maintaining the three to-be-searched colors in VWM rather than the one to-be-excluded color. Now, observers' first few eye movements were directed to items matching the to-be-avoided color no more than predicted by chance (25%) and subsequent eye movements were directed to matching items less than predicted by chance. This indicates that observers are able to exclude known irrelevant items from search when all potentially relevant colors are cued. Results from the current study suggest that it may not be possible to implement an exclusionary attentional template when the to-be-avoided feature is active in VWM. However, when the color to-be-avoided is cued indirectly, our results suggest an exclusionary attentional template can be employed efficiently.