Simultaneous visual adaptation to tilt and displacement: A test of independent processes

Change in both visual direction and visual orientation was assessed following simultaneous exposure to both optical displacement and optical tilt. Tilt adaptation when both transforms were present was not different from tilt adaptation when Ss were exposed to optical tilt alone. A slight decrease in displacement adaptation when the transforms were presented simultaneously was found to be attributable to oblique displacement of the straight-ahead point produced when the optic array is first displaced and then rotated. It was concluded that adaptation to both transforms simultaneously is not different from adaptation to each transform separately, consistent with the view that the two kinds of adaptation involve independent visual systems.