What distinguishes optimal visual searchers? Evidence from a probe procedure

People vary widely in how strategically they guide their attention during visual search. What drives this variation? We contrasted two possibilities: one in which individuals are predisposed to attend to different stimulus aspects, and another in which individuals flexibly choose their strategies depending on the task parameters. Using the Adaptive Choice Visual Search (ACVS) paradigm, we measured participants’ search strategies while probing various display features to index how participants attended the displays. Experiment 1 showed that participants who attended the stimulus properties that are essential for the optimal strategy—specifically, the numerosity subset information—exhibited more optimal performance. In Experiment 2, we made the subset information irrelevant for optimal task performance and found no relationship between attention to the subsets and search optimality, which is consistent with the strategic choice account. Experiment 3 encouraged attention to the subset information without explicitly requiring optimal search. Results showed a boost in optimality, suggesting that overcoming a reluctance to engage in numerosity judgments fosters better strategy use. Overall, these results help to explain individual variation in attentional strategy use, with optimal searchers judiciously directing their attention to process the critical stimulus properties while non-optimal searchers avoid doing so.