Date of Award


Degree Type


Degree Name

Doctor of Philosophy


Despite its considerable use as a psychophysical tool, relatively little attention has been paid to factors that might influence the interocular transfer of the motion aftereffect. The present thesis reports five experiments that examined the role of eye-movements and their interaction with surround contours in the generation and interocular transfer of the motion aftereffect. Experiment 1 compared the amount of transfer of three different aftereffects when the non-adapted eye viewed a dark occluder or an equiluminant occluder. Equiluminant occlusion enhanced interocular transfer of the motion aftereffect but no the other two aftereffects. Experiment 2 showed a similar enhancement of interocular transfer for equiluminant occlusion conditions for motion aftereffects to rotating spokes, but not for aftereffects to rotating spirals nor contracting circles.;During adaptation to certaipes of motion displays, the adapting eye has a tendency to track the display. It was proposed that conjugate tracking generated aftereffects in the surrounding stationary contours in the non-adapted eye viewing the equiluminant occlusion display that resulted in an augmentation of the transfer of treffect. This hypothesis was supported by the results of Experiment 3, in which a ganzfeld was used to occlude the non-adapted eye, eliminating all contour information for that eye. No augmentation of interocular transfer was found following equiluminant ganzfeld occlusion of the non-e. Experiment 4 further supported the hypothesis by demonstrating that augmenting surround contour information red in abnormally high amounts of interocular transfer.;This Experiment also demonstrated that the surround contour-enhanced aftereffects were largely monocular in nature. Experiment 5 replicated these findings, but reduced the augmentation of the transferred aftereffect when subjects viewed a stationary fixation point during adaptation.;The final Experiment examined an aftereffect to pursuit eye-movements in which no stationary contour information was present. While motion aftereffects and their interocular transfer could be demonstrated after large and fast visual pursuit, no such aftereffects were shown for small, slow pursuit distances. These results suggest that the motion aftereffect resulting from pursuit eye-movements is likely to be influential in accounting for the enhancement the aftereffects demonstrated in the earlier experiments.;The augmentation of the motion aftereffect under equiluminant on conditions then, is the result of an aftereffect to stationary surround contours being generated in the "non-adapted" eye. This augments the transferred aftereffect. The results of the present thesis suggest that the motion aftereffect is particularly responsive to relative motion and may be part of the system responsible for detecting object motion.



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