Perception of finger movement under body ownership illusion

Abstract

Body ownership illusions typified by the rubber hand illusion (RHI) have been gaining attention as a phenomenon that directly shows the considerable flexibility of our brain, even on the perception of our own body. Since such illusion occurs when an individual is feeling an integration of own body with other’s body, the perception of other’s body could be altered in some ways under the illusion. Here we investigated how an RHI-like illusion affects the perception of other’s motions, by comparing the performance of detecting finger movement change between two conditions, under illusion and non-illusion. We created a dummy hand in a virtual space using 3-dimensional computer graphics and induced the RHI-like illusion over the hand of the subject by producing visuo-tactile stimulation with a computer-generated animation and a vibration motor. The subject’s task was to detect a small change in motion which was randomly inserted into the repeating cycles of finger movements. Regardless of the fact that there was no visual difference between the two conditions, the detection performance was higher under body ownership transfer illusion. The result suggests that body ownership transfer has an effect on the visual perception of other’s motion.