Abstract
The phenomenon of vection (also referred to as illusive sensation of self-motion) is commonly perceived by stationary observers when watching coherently moving visual stimuli. For oscillatory visual stimuli, relation of the oscillation frequency (f), root-mean-squared (RMS) velocity (v), and amplitude (A), is v=√2πfA. Previous studies in our lab showed that, when stimuli oscillating along the fore-and-aft axis, the influences of frequency on perceived vection depended on amplitude and RMS velocity, which indicated that these three factors had interactive influences on perceived vection. This study examined the effects of these three factors when viewers were watching visual scenes oscillating along the yaw axis. The experiment consisted of 4 repeated sessions in separate days adopting a within subjects design. Subjects were exposed to a virtual optokinetic drum, with alternated black-and-white stripes oscillating sinusoidally. Preliminary data from the first 8 subjects (gender balanced) showed that when visual oscillations were of the same frequency, perceived vection magnitude became stronger first and then turned weaker as the velocity (or amplitude) increased (see supplemental materials). Analyses of the main effects of amplitude indicated that the larger the amplitude, the stronger the perceived vection. However, when the velocity became very large, the increases in perceived vection due to larger amplitude could not compensate the reduction of vection due to the increases in velocity in order to maintain the same frequency. In conclusion, exposure to visual oscillations along the yaw axis of the same frequency but different amplitudes and velocities could generate different vection magnitudes due to the interacting effects of velocity and amplitude. Findings suggested that frequency alone should not be regarded as a sufficient predictor for perceived vection magnitude.
Meeting abstract presented at VSS 2017