Abstract
Our laboratory has proposed that foveal color perception of monochromatic stimuli differs from that in the peripheral retina even when stimulus size is appropriately scaled and rod signals are minimized. The precise nature of the color differences and what they imply about neural processing of color perception remains somewhat elusive, though data from our laboratory and others are beginning to converge on a possible explanation for these differences. In this study, hue-naming functions were obtained in the fovea and at 10° retinal eccentricity along the vertical and horizontal meridians at various test sizes (0.098° to 5.0°) and under experimental conditions chosen to minimize (bleach) and maximize rod input (no bleach). Unique hue loci were assessed directly from the hue-naming functions as well as derived from the Uniform Appearance Diagram. Preliminary analyses show that each unique hue locus converges to essentially the same value across the four retinal quadrants with the larger stimulus size. The peripheral unique hue loci from both the bleach and no-bleach conditions, however, are at shorter wavelengths than comparable foveal unique hue loci. The results will be discussed in relation to stimulus size, retinal location, and rod signals, as well as from an ecological perspective.