Electronic Thesis and Dissertation Repository


Master of Science




Dr. Brian Timney


We used a psychophysical approach to investigate how alcohol affected visual sensitivity to perceive different classes of motion. Visual sensitivities were measured in both a non-alcohol and an alcohol condition for three classes of motion: Minimum Motion, Simple Motion, and Complex Motion. Perceptual thresholds, taken as the degree of motion at which an observer responded correctly with an accuracy of 75%, or Weber fractions were compared between the non-alcohol and the alcohol conditions. For Simple and Complex motion, similar comparisons were made as a function of speed (e.g., 2°s-1, 6°s-1, and 12°s-1). Perceptual thresholds were significantly greater in the alcohol condition for the Minimum Motion, and were significantly greater in the alcohol condition for Complex Motion at the fast speed only. We concluded that deficits in motion perception were more from interruptions in cognitive elements brought about by the nature of the visual task, rather than impairments in sensory processing.