Manipulating the Sense of Embodiment in Virtual Reality: a Study of the Interactions Between the Senses of Agency, Self-location and Ownership

Abstract

In Virtual Reality (VR), the Sense of Embodiment (SoE) corresponds to the feeling of controlling and owning a virtual body, usually referred to as an avatar. The SoE is generally divided into three components: the Sense of Agency (SoA) which characterises the level of control of the user over the avatar, the Sense of Self-Location (SoSL) which is the feeling to be located in the avatar and the Sense of Body-Ownership (SoBO) that represents the attribution of the virtual body to the user. While previous studies showed that the SoE can be manipulated by disturbing either the SoA, the SoBO or the SoSL, the relationships and interactions between these three components still remain unclear. In this paper, we aim at extending the understanding of the SoE and the interactions between its components by 1) experimentally manipulating them in VR via a biased visual feedback, and 2) understanding if each sub-component can be selectively altered or not. To do so, we designed a within-subject experiment where 47 right-handed participants had to perform movements of their right-hand under different experimental conditions impacting the sub-components of embodiment: the SoA was modified by impacting the control of the avatar with visual biased feedback, the SoBO was altered by modifying the realism of the virtual right hand (anthropomorphic cartoon hand or non-anthropomorphic stick ''fingers'') and the SoSL was controlled via the user's point of view (first or third person). After each trial, participants rated their level of agency, ownership and self-location on a 7-item Likert scale. Results' analysis revealed that the three components could not be selectively altered in this experiment. Nevertheless, these preliminary results pave the way to further studies.