Visually induced circular vection (CV) has been the subject of many functional brain studies and behavioral studies. Unfortunately, participants in functional brain studies were in supine position while participants for behavioral studies were in upright positions. Consequently, their findings are confounded with viewing positions and there is no reported study comparing the effects of upright and supine positions on CV perception. This thesis examines the effects of viewing positions and their interactions with different angular velocity of the stimuli (2, 4, 8, 16, 32, 64 degree/second). Experiment 1 started with a rotating color dot pattern commonly used to provoke CV in functional brain studies. Effects of replacing the color dots with gray and black dots were investigated w...[ Read more ]

Visually induced circular vection (CV) has been the subject of many functional brain studies and behavioral studies. Unfortunately, participants in functional brain studies were in supine position while participants for behavioral studies were in upright positions. Consequently, their findings are confounded with viewing positions and there is no reported study comparing the effects of upright and supine positions on CV perception. This thesis examines the effects of viewing positions and their interactions with different angular velocity of the stimuli (2, 4, 8, 16, 32, 64 degree/second). Experiment 1 started with a rotating color dot pattern commonly used to provoke CV in functional brain studies. Effects of replacing the color dots with gray and black dots were investigated with different rotating velocities. Experiment 2 investigated the interacting effects of velocity and viewing position (upright and supine position) on CV. Results showed that red, gray, and black dots provoked similar levels of CV. Results also indicated that CV with the longest accumulated and average duration occurred at 32 deg/sec for supine position and at 8, 16 and 32 deg/sec for upright position. In addition, at slow velocities (2, 4 and 8 deg/sec), subjects perceived CV with longer accumulated and average duration when they were sitting in an upright position than lying in a supine position. Original data on accumulated and average CV duration under different velocities and body positions provide a vital link between findings of functional brain studies and behavioral studies. The findings that different CV are generated from supine and upright positions need to be further explored in the future.