The persistent low-prevalence effect in unfamiliar face-matching: The roles of feedback and criterion shifting.

In visual search, relatively infrequent targets are more likely to be "missed," a phenomenon known as the low-prevalence effect (LPE). Across five experiments, we examined the LPE in unfamiliar face matching, focusing on the roles of feedback and criterion shifting. Across experiments, observers made identity match/mismatch decisions to photograph pairs, and we manipulated target (i.e., identity mismatch) prevalence. Experiment 1 established the necessity of feedback for the LPE; observers were only sensitive to prevalence disparities when provided trial-level feedback. In Experiment 2, target prevalence affected decision criteria, without concomitant effects on perceptual sensitivity. In Experiments 3 through 5, we adopted a "retraining" paradigm, in which observers encountered blocks of high-prevalence targets midway through four 50-trial face-matching quartiles. High-prevalence targets were visually obvious (Experiment 3) or less obvious (Experiments 4 and 5). Whereas observers in equal-prevalence conditions remained unbiased throughout the experiments, those in low-prevalence conditions adopted conservative criteria by the second quartile. This criterion shift was largely resistant to "unbiasing" efforts. Only Experiment 5, which used an 18-item retraining block, revealed a successful (albeit slight) third-quartile liberal criterion shift, but observers were strongly conservative again by the fourth quartile. We discuss the applied and theoretical consequences of these results. (PsycINFO Database Record (c) 2018 APA, all rights reserved).