Abstract
Visual search, by definition, entails confirming whether an object of interest is present or not. However, the role of disconfirmation in search is often overlooked. For example, imagine that you are at a party, and your friend asks you to retrieve an apple that he spotted earlier on the fruit platter. Apples are typically red, so you direct your attention to red fruit. However, the only red fruit that you find are strawberries. You therefore conclude that the apple must be green, by process-of-elimination. Recent research from Rajsic, Wilson, & Pratt (2015) suggests that people are biased to use a confirmatory strategy when searching, however, even when that strategy is not optimal. Their participants searched through displays of letters presented in two possible colors, indicating whether or not a target letter matched an initially-provided template color. Critically, the optimal strategy was always to restrict search to the smaller subset of colored letters, using process-of-elimination if necessary (e.g., if 25% are red and 75% are green, only look at the red letters). Nonetheless, people perseverated in searching through template-matching colors (i.e., even when the majority of letters matched the template color, entailing more laborious search). Might people adopt a more flexible strategy when the target letter only rarely occurs in the template-matching color? We examined this question by manipulating the prevalence of template-matching and template-mismatching targets. We also had participants terminate search and verify the target with separate responses to minimize motor errors. When targets frequently matched the template color, people largely used a confirmatory strategy. However, people adopted a more flexible strategy when template-matching targets were rare, and, surprisingly, when target colors were equally probable, in stark contrast to Rajsic, et al. (2015). These results suggest that the search strategies that people adopt are more malleable than previous findings suggest.
Meeting abstract presented at VSS 2016