Abstract
Subsequent Search Misses (SSMs) are a source of search errors where a second target is missed after a first is detected. “Satisfaction” (i.e., do observers prematurely quit after finding a target) predicts individual’s SSMs (Adamo et al., 2018) and “expectancy,” (i.e., do observers expect another target after finding a first) is predicted to account for “satisfaction” (Stothart & Brockmole, 2019). Because prevalence (how often any target appears) and relative-prevalence (the ratio of single-to-dual target trials) are known to impact search (Cheng & Rich, 2018; Wolfe et al., 2005), we investigated whether they impact satisfaction and SSMs. That is, if observers rarely expect to find a target, and rarely expect multiple targets, does this impact satisfaction’s relationship to second-target misses? Across six experiments, we manipulated relative-prevalence (4:1 or 1:4 single-to-dual target trials) across three different prevalence levels (100%, 50%, and 10% prevalence). As prevalence decreased, we found: 1) when observers expected a second target, satisfaction remained a predictor of second-target misses, but observers were just as likely to find a target on single-target trials compared to a second target (after a first target was detected) on dual-target trials. 2) When observers expected only a single target, they were more likely to find a target on single-target trials compared to a second target on dual-target trials, but satisfaction was less likely/did not predict second-target misses. Taken together, these findings suggest that in low- compared to high-prevalence searches: 1) the SSM effect is less likely to occur when observers expect multiple targets and 2) satisfaction is less likely to predict second-target misses when observers expect only one target in a display. Practically, this suggests that high-prevalence multiple-target searches often used in lab studies lab may not be indicative of SSMs in low-prevalence, real-world searches such as those conducted by baggage screeners and radiologists.