Effect of Avatar Anthropomorphism on Bodily Awareness and Time Estimation in Virtual Reality

The time elapsed during a virtual reality (VR) experience is estimated to be short. Time estimation, a feeling related to timescales longer than a few seconds, is thought to be related to interoception. The shortening of time estimation may be caused by the VR experience distorting bodily awareness based on interoception; however, the details of this change have not been clarified. The characteristics of avatars are likely to affect bodily awareness. Therefore, based on the hypothesis that bodily awareness during a VR experience is altered by manipulating the avatar's degree of anthropomorphism, this study investigated the effect of avatar anthropomorphism on bodily awareness and time estimation. In an experiment, participants performed a heartbeat discrimination task and a one-minute time estimation task, in the real world (Real condition), in the virtual world using a human avatar (VR-Human condition), and in the virtual world using a robot avatar (VR-Robot condition). The results showed that the perceived sense of agency was significantly lower in the VR-Human condition than in the VR-Robot condition, and interoceptive accuracy was significantly higher in the VR-Human condition than in the VR-Robot condition. However, there were no differences in time estimation between conditions. These results indicate that it is possible to conduct experiments to manipulate bodily awareness by manipulating the avatar characteristics. These findings can provide insights into understanding the relationship between bodily awareness and time estimation.