Set-size and chromatic uncertainty in an accuracy visual search task

• Published in: Vision research (Oxford) Vol. 41; no. 28; pp. 3817 - 3827
• Main Authors: Monnier, Patrick, Nagy, Allen L
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01.12.2001; Elsevier Science
• Subjects: Adult; Attention; Attention - physiology; Biological and medical sciences; Color; Color Perception - physiology; Fundamental and applied biological sciences. Psychology; Humans; Male; Perception; Psychology. Psychoanalysis. Psychiatry; Psychology. Psychophysiology; Psychometrics; Sample Size; Signal Detection, Psychological - physiology; Uncertainty; Vision; Visual Perception - physiology; Visual search; Uncertainty; Visual search; Attention; Color; Human; Simulus number; Perception threshold; Vision; Perception; Chromaticity; Experimental study; Visual attention
• ISSN: 0042-6989; 1878-5646
• DOI: 10.1016/S0042-6989(01)00240-1

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.