The contributions of central versus peripheral vision to scene gist recognition.

Which region of the visual field is most useful for recognizing scene gist, central vision (the fovea and parafovea) based on its higher visual resolution and importance for object recognition, or the periphery, based on resolving lower spatial frequencies useful for scene gist recognition, and its large extent? Scenes were presented in two experimental conditions: a "Window," a circular region showing the central portion of a scene, and blocking peripheral information, or a "Scotoma," which blocks out the central portion of a scene and shows only the periphery. Results indicated the periphery was more useful than central vision for maximal performance (i.e., equal to seeing the entire image). Nevertheless, central vision was more efficient for scene gist recognition than the periphery on a per-pixel basis. A critical radius of 7.4 degrees was found where the Window and Scotoma performance curves crossed, producing equal performance. This value was compared to predicted critical radii from cortical magnification functions on the assumption that equal V1 activation would produce equal performance. However, these predictions were systematically smaller than the empirical critical radius, suggesting that the utility of central vision for gist recognition is less than predicted by V1 cortical magnification.