title: Low target prevalence is a stubborn source of errors in visual search tasks.
abstract: In visual search tasks, observers look for targets in displays containing distractors. Likelihood that targets will be missed varies with target prevalence, the frequency with which targets are presented across trials. Miss error rates are much higher at low target prevalence (1%-2%) than at high prevalence (50%). Unfortunately, low prevalence is characteristic of important search tasks such as airport security and medical screening where miss errors are dangerous. A series of experiments show this prevalence effect is very robust. In signal detection terms, the prevalence effect can be explained as a criterion shift and not a change in sensitivity. Several efforts to induce observers to adopt a better criterion fail. However, a regime of brief retraining periods with high prevalence and full feedback allows observers to hold a good criterion during periods of low prevalence with no feedback.
authors.affiliation: Visual Attention Lab, Brigham and Women's Hospital, Cambridge, Massachusetts 021139-4170, USA. wolfe@search.bwh.harvard.edu
authors.forename: Jeremy M
authors.initials: JM
authors.lastname: Wolfe
authors.forename: Todd S
authors.initials: TS
authors.lastname: Horowitz
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Van Wert
authors.forename: Naomi M
authors.initials: NM
authors.lastname: Kenner
authors.forename: Skyler S
authors.initials: SS
authors.lastname: Place
authors.forename: Nour
authors.initials: N
authors.lastname: Kibbi
mesh_terms: D000328:Adult; D001288:Attention; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D011584:Psychology / Q000706:statistics & numerical data; D011930:Reaction Time; D021641:Recognition, Psychology; D012637:Security Measures / Q000706:statistics & numerical data*; D017603:Signal Detection, Psychological; D014796:Visual Perception