Abstract
In a visual search task of a color oddball, we study the effects of color preview on search RTs. When the search display contains an odd colored diamond (e.g., a red diamond among green diamonds), the task is to indicate the side of the odd diamond on which a notch is present (go trials). When the search display contains all diamonds of a single color, no response is needed (no-go trials). The Distractor Previewing Effect (DPE, Goolsby & Suzuki, 2001) is the finding that RTs are substantially shorter when the distractor diamonds in the go trial are of the same color as the diamonds in the preceding no-go trial (e.g., green distractors following a green no-go display) than when the target in the go trial is of the same color as the diamonds in the immediately preceding no-go trial (e.g., red target following a red no-go display). Importantly, observers do not know in advance whether a trial will be go or no-go. In the present study, we tested the hypothesis that the DPE reflects response-related suppression due to the automatic processing of items in the preview displays as task-relevant items. Experiment 1 investigated whether the DPE persists when observers have foreknowledge of the type of display (go or no-go) they will see next, by providing a cue. We found that foreknowledge of display type significantly reduced the magnitude of the DPE. Experiment 2 asked whether the DPE persists when observers produce a speeded response to single-color displays. We found that the DPE was modulated by the go/no-go nature of the single-color displays. In Experiment 3, a neutral color was added to the displays to test whether the suppression is specific to the target item or whether it extends to distractor items. Our results indicated that both target and distractors items that are of the same color as the items in the no-go display are suppressed and that the suppression is dependent on the go/no-go nature of the single color display.