Abstract
When searching for a target, the presence of a salient but non-relevant distractor typically interferes with selection. Interference can be reduced e.g., by down-weighting of the distractor dimension when target and distractor features do not overlap, or by down-weighting the location where the distractor is most likely to occur. Here, we analyze selection errors to examine how feature similarity affects attentional capture and distractor location learning. In three experiments, participants searched for a unique shape target in a display with heterogeneous (Exp. 1 and 2) or homogeneous (Exp. 3) non-targets with a color distractor presented in some trials that was more likely to appear at a particular location. A unique digit was embedded in each search item, and digit reports served as an index of selection behavior: correct target selection (target reports), attentional capture (distractor reports) or as baseline (non-target reports). In Expt. 1 and 2 target and non-target color remained constant (Exp 1: color; Exp. 2: grey) across trials, allowing participants to use feature search to find the target. In Expt. 3, target and distractor colors swapped unpredictably, forcing participants into singleton search. As expected, we found pronounced attentional capture and distractor location learning in the color-swap condition (Exp. 3), but no sign of capture nor distractor location learning with constant target color and heterogeneous non-targets (Exp. 1). Interestingly, results showed substantial capture also with grey non-targets (Exp. 2). As in the color-swap condition, distractor reports decreased over time, but only the color-swap condition showed a difference between high- and low-probability locations. This suggests that with grey non-targets, participants neither fully relied on feature search nor on distractor location learning, but on another mechanism to handle distraction. Overall, these results indicate that participants can flexibly adjust their target template to maximize the distinctiveness between the target and distractor features.