Abstract
Previous studies on “oddball” visual search have shown that the relative match/mismatch between the features in an oddball-absent trial and those in the subsequent oddball-present trial greatly influences reaction times (RT) to oddball-present displays, an effect known as the distractor previewing effect (DPE). For example, in a color-oddball task, RTs to a red diamond presented among two green diamonds are (1) decreased if three green diamonds were previewed in the preceding trial and (2) increased if three red diamonds were previewed in the preceding trial, compared to a non-previewed color baseline (e.g., gray). Importantly, in DPE tasks, participants respond to a second feature of the target (e.g., shape), totally uncorrelated to the oddball feature (color in this example). We refer to these two types of features as the “response feature” and “defining feature” of the target, respectively. Here we investigated what combinations of response and defining features lead to the DPE. In separate experiments, we used the following response and defining features: topological oddballs (open vs close surfaces), two levels of color discrimination (red vs. green and yellowish-red vs blueish-red), and two levels of closed-shape discriminations (triangles vs. circles and diamonds missing-right vs missing-left corners). Our results showed a generalization of the DPE to visual searches in which the defining features of the target allow for efficient surface segmentation of oddball-present displays. Implications for models of visual search and pop-out search are discussed.