Abstract:

PURPOSE: Perception and action are interdependent. How visual information guide movements has been extensively studied, while how movements affects vision is understudied. We postulate that moving in an altered visual environment can modify well-established representations of the world such as visual perspective.
Methods: Here we invert the rules of perspective in virtual reality by modifying the size-distance relation from distant objects appearing smaller, the normal case, to distant objects appearing larger. In the pretest and posttest, we measured the magnitude of Ponzo illusion as a quantification of perception of perspective.
During adaption, subjects wore a head-mounted display and a data glove. Subjects were divided into 3 groups. For the active group, subjects actively engaged with the special virtual scene for 30 mins: they were required to push a virtual ball. The ball rolled and stopped at a target gate. Before each push, subjects adjusted the gate width to predictively minimize the discrepancy between the gate and the ball. For the passive group, visual manipulations remained the same but subjects passively watched the ball rolling away. For the control group, subjects performed the same task as the active group but with a normal perspective.
RESULTS: We computed the reduction of illusion size between pretest and posttest to examine how VR exposure affected perception. Both active and passive groups had significant changes (paired t-test, p<0.05) with significant difference between groups (ANOVA, p<0.05). Post-hoc tests only detected that the active group had larger effect than the control group (p<0.05). This shows that actions in VR can facilitate the change in perception of perspective.
CONCLUSIONS: Our study suggests that immersion in an altered visual environment can change our well-established perceptual representation and motoric interaction can facilitate this change. Immersive VR offers an effective tool to study the interaction between perception and action by quickly reshaping their existing relations.

Key words: visual perspective, virtual reality, Ponzo illusion