Professions such as radiology and aviation security screening that rely on visual search— the act of looking for targets among distractors—often cannot provide operators immediate feedback, which can create situations where performance may be largely driven by the searchers’ own expectations. For example, if searchers do not expect relatively hard- to-spot targets to be present in a given search, they may find easy-to-spot targets but systematically quit searching before finding more difficult ones. Without feedback, searchers can create self-fulfilling prophecies where they incorrectly reinforce initial biases (e.g., first assuming and then, perhaps wrongly, concluding hard-to-spot targets are rare). In the current study, two groups of searchers completed an identical visual search task but with just a single difference in their initial task instructions before the experiment started; those in the “high-expectation” condition were told that each trial could have one or two targets present (i.e., implying no target-absent trials) and those in the “low-expectation” condition were told that each trial would have up to two targets (i.e., implying there could be target-absent trials). Compared to the high-expectation group, the low-expectation group had a lower hit rate and quit trials more quickly, consistent with a lower quitting threshold (i.e., performing less exhaustive searches). The expectation effect was present from the start and remained across the experiment—despite exposure to the same true distribution of targets, the groups’ performance remained divergent, primarily driven by the low-expectation group’s self-fulfilling prophecy that stemmed from the simple instructions difference. In sum, initial expectations can have dramatic influences— searchers who do not expect to find a target, are less likely to find a target as they are more likely to quit searching faster.
Immediate Feedback During Multiple-Target Visual Search Improves Accuracy