Figural after-effects, retinal size and apparent size.

Abstract

Previous work has established that figural after‐effects are determined by the retinal size of the inspection figure, but Sutherland (1954) has argued that the methods used were based on the assumption that retinal and apparent sizes cannot both be determinants. He himself has provided evidence of the effects of apparent size. The present paper reports an experiment intended to confirm Sutherland's findings and to measure the magnitude of the after‐effects, if any. Eleven subjects were required to equate two test‐figures after prolonged fixation of prior inspection figures. One inspection figure was retinally equal, apparently larger, the other, retinally equal, apparently smaller than a test‐figure. In the first case, the test‐figure decreased significantly, in the second it decreased, but not significantly. It is held that these results can be explained by assuming both retinal and apparent sizes to be effective, in the first case acting together and in the second opposing one another.