Sustained deviation of gaze direction can affect "inverted vection" induced by the foreground motion.

A slowly moving foreground with an orthogonally moving background can induce self-motion perception in the same direction as the foreground motion (inverted vection; [Vision Research 40 (2000) 2915]). In the present study, we investigate the effect of sustained gaze deviation on inverted vection. We hypothesized that gaze deviation affects eye-movement information registered in the perceptual system, which might be a primary factor for causing inverted vection. The experiment revealed that strength of inverted vection decreases with observer's gaze deviation in the same direction as the foreground motion, while it increases with the deviation in the opposite direction to the foreground. These results support our hypothesis and suggest that inverted vection is affected by eye-movement information.