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Elucidating Visual Search Behavior and Resulting Performance in Low Prevalence Dynamic Search

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[Technical Report, Technical Report]

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Visual search is an essential element of various professions, such as airport security screening, radiology, and sonar monitoring, in which accurate and efficient task performance is vital. Visual search performance is dependent on specific search conditions, such as the frequency of targets, if targets are moving or stationary, and the duration of target visibility. Despite existing research on how conditions such as these individually influence search performance, the extent to which they interact-particularly target prevalence in different types of search environments-is unclear. Therefore, this study investigated performance and perceived cognitive demands of three common aspects of visual search target prevalence 50 vs 10 , display type static still-image vs. dynamic continuous scroll, and display time 3.5 vs. 7 seconds. Participants n 556 recruited through Amazon Mechanical Turk were randomly assigned to one of eight experimental conditions created from the combinations of these search conditions. Participants were tasked with detecting known targets, Ts, among a display of distractors, offset Ls, and subsequently rating their perceived condition-specific cognitive task workload via the NASA Task Load Index NASA-TLX. Though no significant interactions between search conditions on accuracy were found, condition-specific effects were present. Lower target prevalence produced decreased hit rates, replicating the Low Prevalence Effect LPE Wolfe et al., 2007, across static and dynamic displays. Additionally, NASA-TLX ratings implies observer blindness to actual performance decrements in low target prevalence searches. The persistence of the LPE highlights the need for LPE-mitigation methods in both types of search environments.

Subject Categories:

  • Target Direction, Range and Position Finding

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[A, Approved For Public Release]