First-Person Perspective Virtual Body Posture Influences Stress: A Virtual Reality Body Ownership Study.

Ilias Bergström,Mel Slater,Konstantina Kilteni,Matthew Longo

doi:10.1371/journal.pone.0148060

Abstract

In immersive virtual reality (IVR) it is possible to replace a person’s real body by a life-sized virtual body that is seen from first person perspective to visually substitute their own. Multisensory feedback from the virtual to the real body (such as the correspondence of touch and also movement) can also be present. Under these conditions participants typically experience a subjective body ownership illusion (BOI) over the virtual body, even though they know that it is not their real one. In most studies and applications the posture of the real and virtual bodies are as similar as possible. Here we were interested in whether the BOI is diminished when there are gross discrepancies between the real and virtual body postures. We also explored whether a comfortable or uncomfortable virtual body posture would induce feelings and physiological responses commensurate with the posture. We carried out an experiment with 31 participants in IVR realized with a wide field-of-view head-mounted display. All participants were comfortably seated. Sixteen of them were embodied in a virtual body designed to be in a comfortable posture, and the remainder in an uncomfortable posture. The results suggest that the uncomfortable body posture led to lesser subjective BOI than the comfortable one, but that participants in the uncomfortable posture experienced greater awareness of their autonomic physiological responses. Moreover their heart rate, heart rate variability, and the number of mistakes in a cognitive task were associated with the strength of their BOI in the uncomfortable posture: greater heart rate, lower heart rate variability and more mistakes were associated with higher levels of the BOI. These findings point in a consistent direction—that the BOI over a body that is in an uncomfortable posture can lead to subjective, physiological and cognitive effects consistent with discomfort that do not occur with the BOI over a body in a comfortable posture.

Highlights

Imagine being seated on an aeroplane in an uncomfortable posture, but through wearing a head-mounted display you see in immersive virtual reality that the life-sized virtual body that substitutes your own is in a comfortable posture
In this paper we address the question of whether the posture of a life-sized virtual body that is seen by participants from first person perspective (1PP), and that is different from their actual posture, affects the level of the body ownership illusion (BOI) and whether it influences feelings of comfort and discomfort and corresponding physiological state in the participants
In the current study we aimed to test whether virtual body posture seen from 1PP and in a mirror would influence the illusion of body ownership of participants, their feelings of comfort or discomfort, and associated physiological responses

Summary

Introduction

Imagine being seated on an aeroplane in an uncomfortable posture, but through wearing a head-mounted display you see in immersive virtual reality that the life-sized virtual body that substitutes your own is in a comfortable posture. Would this induce feelings of comfort in spite of your actual uncomfortable posture? Participants see a mannequin at the same location as their own body (as if collocated), through a head mounted display (HMD), and from 1PP When their real body is stroked in synchrony with strokes seen to be applied to the mannequin body they have a BOI with respect to that body [11, 12]

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