Double body effect induced by integrating proprioceptive-vestibular and visual information.

Abstract

Most studies in bodily self-consciousness were limited to the case of a single body. We performed VR experiments to test the hypothesis that it is possible for healthy subjects to experience the Double Body Effect-the experiential combination of double body ownership and double body-location. Under proprioceptive-vestibular and visual manipulations, participants wobbled involuntarily while watching two identical avatars doing exactly the same. The results showed that, in both the 1PP and 3PP conditions, it was indeed possible for healthy subjects to experience the Double Body Effect. This reveals that body ownership and body location are more flexible than most studies have considered so far. It also suggests that self-location and body-location are not the same experiences, and that the relation between self and body is more complicated than both traditional dualism and contemporary reductionism. Finally, our findings can serve as a preliminary model for understanding the perplexing phenomenology of heautoscopy.