Where are you? Self- and body part localization using virtual reality setups

Book excerpt: This volume presents a line of original experimental studies on the bodily self, investigating where people locate themselves in their bodies and how accurate they are at localizing their body parts. So far, it was not well known whether people locate themselves in one or more specific regions of their bodies. On the other hand, some systematic distortions in indicating bodily locations were already documented. In the present studies, participants were therefore asked to indicate their self-locations, as well as the locations of several of their body parts, using a self-directed, first-person perspective pointing paradigm in various virtual reality (VR) setups (different head-mounted displays and a large-screen immersive display). Overall, participants were found to locate themselves mainly in the (upper) face and the (upper) torso. However, striking differences in self-localization were found when testing in different VR setups. Upon further investigation, these differences were found to be foremost due to inaccuracies in body part localization. When taking these inaccuracies into account, differences between setups—and also with self-localization outside of VR—largely disappear. Another striking finding was that providing participants—in between pointing phases—with information about their bodies in the form of a real-time animated self-avatar, did not make them more accurate at locating their own body parts. While manipulating their viewpoint to chest-height of their self-avatar did shift the afterwards indicated locations of their own body parts upwards, towards where they were seen on the avatar. Potential explanations for the various new findings, also from tasks outside of VR, are discussed. Taken together, this volume suggests a differential involvement of multi-sensory information processing in experienced self-location within the body and the ability to locate body parts. Self-localization seems to be less flexible, possibly because it is strongly grounded in the 'bodily senses', while body part localization appears more adaptable to the manipulation of sensory stimuli, at least in the visual modality.