Apparent modifiability of receptive fields during accommodation and convergence and a model for size constancy

Abstract

The size of Ricco's summation area can be altered by changing accommodation and convergence (A-C). For foveal stimuli of fixed retinal size, the change in Ricco's area is approximately the same as the change in apparent size induced by the A-C factors. As distance from the foveola increases, the A-C effect becomes smaller. However, size constancy is also rapidly lost outside the fovea. Therefore, the changes in Ricco's area and size constancy seem to be correlated for at least two parameters, namely A-C factors and retinal position. Assuming that the Ricco area reflects receptive field size, the effects of retinal position and A-C factors on the Ricco area suggest a model for size constancy.