Abstract

Shifts in perceived spatial frequency as a function of contrast obtained at 0° and 8° eccentricity of the visual field show that the direction of the shifts may not be constant throughout the range of frequencies tested. The perceived frequency of a grating viewed in the periphery, however, always appears to be of higher frequency than one viewed in the fovea. A multiple-channel model which incorporates retinal inhomogeneity may account for these results. Factors such as (1) receptive field size, (2) perceptual spatial frequency labels attached to the ouputs of mechanisms, (3) relative sensitivity of peripheral mechanisms compared with foveal mechanisms, and (4) relative steepness and nonlinearity of contrast transfer functions following the output of peripheral mechanisms compared with foveal mechanisms, can all influence the appearance of visual patterns. Shifts predicted by larger receptive field sizes in the periphery are consistent with the data whereas those predicted by lower spatial frequencies of perceptual labels in the periphery are not. (The other two factors have only a small effect.)

© 1985 Optical Society of America