Figure 1.

(a) Stimulus configuration for the traditional MAE. The subjects’ task was to indicate the direction of motion of the test. An adaptive algorithm adjusted the physical velocity of the test to home in on the null point. (b) Stimulus configuration for the PMAE. Subjects indicated which of the two test patches appeared more rightward. Again, an adaptive algorithm adjusted the physical positions of the stimuli to home in on the point of perceived alignment. (c) Experimental conditions. After adaptation four different conditions were tested: full adaptation, where no saccade occurred between the adaptation and the test, so both were in the same position in space and on the retina; spatiotopic, where the adaptor and test were in the same screen position but different retinal positions; retinotopic, in the same retinal but different screen positions; and unmatched, where the test was displayed at a location that was neither retinotopically nor spatiotopically adapted.