The phenomenon of vection (also termed as self-motion illusions) is commonly perceived by stationary observers when watching coherently moving visual stimuli. For oscillatory visual stimuli, the effects of oscillation frequency on vection along the fore-and-aft axis have been studied with fixed velocity and fixed amplitude by Chen (2014). The two-frequency-response hypothesis, which explained inconsistent effects of frequency in literature, was proposed. This dissertation extends his work to yaw and roll visual oscillations. Effects of frequency, velocity, and amplitude are investigated. Two experiments for yaw and roll vection were conducted respectively. In each experiment, there were five levels of frequency, rms velocity, and amplitude. Results showed that under constant rms...[ Read more ]

The phenomenon of vection (also termed as self-motion illusions) is commonly perceived by stationary observers when watching coherently moving visual stimuli. For oscillatory visual stimuli, the effects of oscillation frequency on vection along the fore-and-aft axis have been studied with fixed velocity and fixed amplitude by Chen (2014). The two-frequency-response hypothesis, which explained inconsistent effects of frequency in literature, was proposed. This dissertation extends his work to yaw and roll visual oscillations. Effects of frequency, velocity, and amplitude are investigated. Two experiments for yaw and roll vection were conducted respectively. In each experiment, there were five levels of frequency, rms velocity, and amplitude. Results showed that under constant rms velocity, yaw vection decreased as frequency increased; and under constant amplitude, yaw vection presented an inverted U-shape with increasing frequency. Thus, frequency response for yaw vection supported the two-frequency-response hypothesis. As for roll vection, vection dropped as frequency increased no matter whether rms velocity or amplitude was fixed. It was also found that visual oscillations of the same frequency but different amplitudes and velocities generated different vection magnitudes for both yaw and roll vection. Findings suggested that frequency alone should not be regarded as a sufficient predictor for perceived vection magnitude. Analyses of the effects of amplitude indicated that the larger the amplitude, the stronger the vection. As for the effects of velocity, yaw vection presented an inverted U-shape with increasing velocity; while roll vection decreased as velocity increased. Interestingly, three different frequency responses of vection provoked by constant amplitude visual oscillation were found for yaw, roll and fore-and-aft vection. This suggested that there might be different motion perception mechanisms for visual system along different directions.