Apparent distance vs. apparent size as determiners of figural after-effects

Abstract.— Sutherland's (1954) much discussed experimental design was analysed in a new fashion. When the original experiment was repeated as such, the expected FAE was found. However, when the same IFs and TFs were presented in a vertical position, no significant FAEs were found. The results lend support to the interpretation presented earlier by Kolehmainen (1968): The FAE found by Sutherland was apparently due to an uncontrolled binocular disparity resulting in a different localization of stimulus figures in respect to the fixation point.