The individual and relative contributions of different regions of the visual field to visual search
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Greenwood Mears, Ruth
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The individual and relative contributions of foveal, central and peripheral vision to object-scene search were assessed using the window and scotoma paradigms. The visual field simulation (window or scotoma and a control), crossed with 3 radii of window or scotoma (1.5°, 5° or 8.6°) was centred on the viewer’s gaze using a Gaze Contingent Multiresolutional Display. Windows and scotoma had smoothedged boundaries and visual information which was restricted from contributing to the visual task was presented in low-resolution. It was found that foveal information was neither necessary nor sufficient for visual search. This replicated previous findings (Nuthmann, 2010). Central and peripheral information were both found to be necessary but not sufficient for normal visual search. The contribution of central information was found to be of greater importance than the contribution of peripheral information. A cross-over point at which search performance was the same in both the window and scotoma conditions was found, at a radius slightly smaller than 5°. At this radius less area was presented in high-resolution in the window condition, indicating that central information is privileged relative to peripheral information. It was found that the perceptual span for visual search was 8.6°.