title: Perceptual failures in the selection and identification of low-prevalence targets in relative prevalence visual search.
abstract: Previous research has shown that during visual search tasks target prevalence (the proportion of trials in which a target appears) influences both the probability that a target will be detected, and the speed at which participants will quit searching and provide an 'absent' response. When prevalence is low (e.g., target presented on 2 % of trials), participants are less likely to detect the target than when prevalence is higher (e.g., 50 % of trials). In the present set of experiments, we examined perceptual failures to detect low prevalence targets in visual search. We used a relative prevalence search task in order to be able to present an overall 50 % target prevalence and thereby prevent the results being accounted for by early quitting behavior. Participants searched for two targets, one of which appeared on 45 % of trials and another that appeared on 5 % of trials, leaving overall target prevalence at 50 %. In the first experiment, participants searched for two dissimilar targets; in the second experiment, participants searched for two similar targets. Overall, the results supported the notion that a reduction in prevalence primarily influenced perceptual failures of identification, rather than of selection. Together, these experiments add to a growing body of research exploring how and why observers fail to detect low prevalence targets, especially in real-world tasks in which some targets are more likely to appear than others.
authors.affiliation: School of Psychology, University of Southampton, Highfield, Southampton, Hampshire, SO17 1BJ, UK, hayward.godwin@soton.ac.uk.
authors.forename: Hayward J
authors.initials: HJ
authors.lastname: Godwin
authors.forename: Tamaryn
authors.initials: T
authors.lastname: Menneer
authors.forename: Charlotte A
authors.initials: CA
authors.lastname: Riggs
authors.forename: Kyle R
authors.initials: KR
authors.lastname: Cave
authors.forename: Nick
authors.initials: N
authors.lastname: Donnelly
mesh_terms: D003463:Cues; D005133:Eye Movements / Q000502:physiology; D005403:Fixation, Ocular / Q000502:physiology; D005556:Form Perception / Q000502:physiology; D006801:Humans; D010470:Perceptual Masking / Q000502:physiology; D011336:Probability; D011930:Reaction Time / Q000502:physiology; D021641:Recognition, Psychology / Q000502:physiology*; D055815:Young Adult