The Plausibility of a String Quartet Performance in Virtual Reality

Abstract

-We describe an experiment that explores the contribution of auditory and other features to the illusion of plausibility in a virtual environment that depicts the performance of a string quartet. 'Plausibility' refers to the component of presence that is the illusion that the perceived events in the virtual environment are really happening. The features studied were: Gaze (the musicians ignored the participant, the musicians sometimes looked towards and followed the participant's movements), Sound Spatialization (Mono, Stereo, Spatial), Auralization (no sound reflections, reflections corresponding to a room larger than the one perceived, reflections that exactly matched the virtual room), and Environment (no sound from outside of the room, birdsong and wind corresponding to the outside scene). We adopted the methodology based on color matching theory, where 20 participants were first able to assess their feeling of plausibility in the environment with each of the four features at their highest setting. Then five times participants started from a low setting on all features and were able to make transitions from one system configuration to another until they matched their original feeling of plausibility. From these transitions a Markov transition matrix was constructed, and also probabilities of a match conditional on feature configuration. The results show that Environment and Gaze were individually the most important factors influencing the level of plausibility. The highest probability transitions were to improve Environment and Gaze, and then Auralization and Spatialization. We present this work as both a contribution to the methodology of assessing presence without questionnaires, and showing how various aspects of a musical performance can influence plausibility.

“We Wait”—The Impact of Character Responsiveness and Self Embodiment on Presence and Interest in an Immersive News Experience

“…Corroborating evidence is that observing at close hand a virtual musical string quartet, when the virtual performers looked toward the participant the level of plausibility was enhanced. Also the environmental auditory information matching visual elements in the scene also enhanced Psi (Bergstrom et al, 2017). The general issue of coherence between different aspects of the environment was also studied by (Skarbez et al, 2017).…”

“…The "Plausibility Illusion" (Psi) is the illusion that the events depicted in the VR are really occurring (Slater, 2009). This can be facilitated by (i) the virtual world responding to participant actions (ii) contingent events that refer personally to the participant (iii) the extent to which the portrayal of the virtual world and its events conforms to expectations where this is applicable (Bergstrom et al, 2017) and maintains internal consistency (Skarbez et al, 2017). Body ownership is the third illusion, referring to the extent that a virtual self-representation within the VR is illusorily experienced as the participant's own body (Slater et al, 2010b;Blanke et al, 1 https://www.youtube.com/watch?v=_z8pSTMfGSo&t=18s 2015).…”

Immersive VR and Education: Embodied Design Principles That Include Gesture and Hand Controls

“…Several surveys are available for assessing the amount of presence in a mediated experience (Slater and Wilbur, 1997;Makransky et al, 2017). Slater's lab has led extensive research on presence and his group has also pioneered a method for assessing presence without the use of surveys (Bergstrom et al, 2017).…”

Generic HRTFs May be Good Enough in Virtual Reality. Improving Source Localization through Cross-Modal Plasticity

“…To simulate natural acoustic perception in Virtual Reality (VR) these auditory spatial cues are usually rendered using Head Related Transfer Functions (HRTFs), which can either be generic or individualized. The use of HRTFs leads to accurate source localization and increased sense of presence within the virtual environment, when compared to non-spatialized audio (Hendrix and Barfield, 1996 ; Bergstrom et al, 2017 ). Individualized HRTFs are calibrated on a per user basis, and are therefore better suited to simulate one's natural acoustic environment.…”