A temporal analysis of body sway caused by self-motion during stereoscopic viewing

Abstract

While continuously viewing objects in motion, humans may develop an illusionary sense of moving in the opposite direction as the objects, despite being quiescent. This phenomenon is termed as vection. In this study, we investigated the effect of long-duration viewing through binocular stereopsis on vection by measuring the body sway. Subjects watched a static movie for a minute, sinusoidal-motion movie at 0.3 Hz for 3 min, and the initial static movie for a minute, in sequence.Wehad three observations from the results of this study. First, the longer the viewing time, the higher the synchrony with direction of motion in the movie. Stoppage of the motion-movie and returning to viewing a static movie decreases the synchrony gradually. Second, synchrony is higher while viewing a 3D- than a 2D-movie. Third, the body sways in the anteroposterior direction in a cyclical manner by sensing self-motion in the horizontal direction.