title: Set-size and chromatic uncertainty in an accuracy visual search task.
abstract: Thresholds for chromatic differences were measured in a simple visual search task in which the target differed from the distractors in chromaticity only. In Experiment 1, the spatial separation between stimulus elements was varied. Slopes of threshold versus set-size (2-16) for elements in close proximity were somewhat elevated, suggesting non-independence of the stimulus elements. In Experiment 2, chromatic uncertainty was introduced to increase the attentional load beyond that accomplished with the set-size manipulation. The results were accounted for by a model assuming no limit in attention capacity. Furthermore, chromatic uncertainty was successfully modeled as a simple increase in the number of monitored signals.
authors.affiliation: Visual Science Laboratories, University of Chicago, 940 East 57th Street, Chicago, IL 60637, USA.
authors.forename: P
authors.initials: P
authors.lastname: Monnier
authors.forename: A L
authors.initials: AL
authors.lastname: Nagy
mesh_terms: D000328:Adult; D001288:Attention / Q000502:physiology; D003118:Color Perception / Q000502:physiology*; D006801:Humans; D008297:Male; D011594:Psychometrics; D018401:Sample Size; D017603:Signal Detection, Psychological / Q000502:physiology; D014796:Visual Perception / Q000502:physiology*