Different Effect of Passive and Active Hand Movement on 3-D Perception

Abstract

In this study, the effect of active and passive movement of hand on depth perception was compared. In experiments, a mirror was used to coincide a cursor position in a simulated 3-D space with a point of a stylus on a force-feedback device located under the mirror. In ‘passive’ condition, subjects required to touch the center of a square in the visual display by the cursor. Then the square stereoscopically protruded toward subjects or dented. At the same time, the force toward or away from subject was given to the stylus. While in the ‘active’ condition, the subjects themselves push or pull the stylus after touching the square and its surface was synchronously deformed. Although the movement of the stylus and the surface deformation was synchronized in both the conditions, their directions were independently manipulated. Subjects were asked whether the square visually protruded or dented. The results showed that the subjects' answers were biased to the direction of forces given to the stylus. This effect was not observed when subjects actively moved the stylus. These results suggest that information about hand movement or force perception would affect the visual perception when subjects do not have expectations about following visual scenes.