The Perception of Self-Motion Induced by Peripheral Visual Information in Sitting and Supine Postures

Abstract

The effects of speed and direction of a moving peripheral stimulus on the perception of self-motion were studied in sitting and supine postures. Observers sat or lay on their backs with one monitor on each side of their head. On the monitor screens, random dot patterns moved vertically or horizontally under three speed conditions. The latency of the onset of the induced self-motion was shorter under the high-speed condition than under the lower speed conditions. In the sitting posture, the latency was shorter when the patterns moved vertically than when they moved horizontally. In the supine posture, the latency depended neither on the physical nor on the egocentric verticality of the pattern motion. This shows that the effect of direction of moving patterns was not the same in the sitting posture and the supine posture. The results were explained by an informational difference of visual-vestibular interaction in each of these two postures.