Subject(s)
Licensure, Medical , Mass Media , Medical Errors , Public Relations , Amputation, Surgical , Florida , Forms and Records Control , Humans , Informed Consent , Leg/surgeryABSTRACT
Visual search times were measured as a function of chromaticity and luminance differences between a target and distractor stimuli. Results showed that mean search time increased linearly with the number of distractors if the luminance difference between target and distractors was small but was roughly constant if the luminance difference was large. Similar results were previously found for chromaticity differences. With the number of distractor stimuli held constant, the mean search time decreased with increases in the difference between target and distractors, up to some critical difference. Further increases in target-distractor difference had little effect. Results were similar for targets defined by luminance and chromaticity. There was some advantage to combining luminance differences with chromaticity differences when the target was dimmer than the distractors. Generally there was no advantage for combining a chromaticity difference with a luminance difference when the target was brighter than the distractors.
Subject(s)
Attention , Color Perception , Computer Graphics , Data Display , Light , Pattern Recognition, Visual , Adult , Contrast Sensitivity , Female , Humans , Male , PsychophysicsABSTRACT
Color differences required for fast parallel searches were measured for small and large display fields. The main purpose of the measurement was to test the hypothesis that serial searches obtained with small color differences in large display fields are due to poor discrimination in the peripheral visual field and to the need for foveal fixation. Results do not support this hypothesis but show that the color differences required for parallel search are just as large in a display confined to an area roughly the size of the fovea as in a large display. However, results also show that the color difference required for a fast, parallel search is dependent on the size of the stimuli in a large display field. This result is consistent with the possibility that poor discrimination in the periphery may contribute to the size of the required differences if the stimuli are small.
Subject(s)
Color Perception/physiology , Fovea Centralis/physiology , Visual Perception/physiology , Female , Humans , Light , Male , Sensory Thresholds , Visual FieldsABSTRACT
Response times were measured for a visual search task in which the observer was required to find a target that differed from distracting stimuli only in color. In the first experiment the search time was measured as a function of display density for both small and large color differences. With small color differences response time increased with display density, indicating a serial search, but with large color differences response time was constant, indicating a parallel search. In the second experiment the color difference required for parallel search was measured in eight different directions from the distracter chromaticity. These color differences were much larger than threshold color differences and were not well represented by the ellipse used to describe the threshold contour around a point in color space.
