Abstract
It has been well established that attentional control sets occur when observers search the visual field for targets defined by a specific feature. When uninformative peripheral cues precede the target, cues that contain the specific target feature will capture attention while cues that do not will be effectively ignored. We tested whether different attentional control sets can be simultaneously maintained over distinct regions of space. On each trial, either a blue or a green target was presented within one of two placeholders located to the left and to the right of a central fixation cross. Observers were instructed to respond to only specific colored targets at specific locations (i.e., blue target at left placeholder, green target at right placeholder, or vice versa). On most trials, 150 ms before the target was presented, either a blue or a green cue appeared around the left or the right placeholder. These cues varied on two dimensions in relation to the impending targets: they were presented either in the same location (valid) or the opposite location (invalid), and they were either the same color (matching) or the other color (nonmatching). On other trials, no cue was presented. All trial types occurred with equal probability, and response time (RT) to the target was recorded. As expected, trials in which the cue was congruent with the target (valid-matching) elicited the fastest RTs relative to no-cue trials, while fully incongruent trails (invalid-nonmatching) elicited the longest RTs. Importantly, the partially incongruent trials (valid-nonmatching and invalid-matching) elicited RTs that did not differ from no-cue trials. This is the first demonstration that two separate attentional control sets can be simultaneously maintained at distinct spatial locations.