Representing inner voices in virtual reality environments

The inner auditory experience comprises various sounds which, rather than originating from sources in their environment, form as a result of internal processes within the brain of an observer. Examples of such sounds are, for instance, verbal thoughts and auditory hallucinations. Traditional audiovisual media representations of inner voices have tended to focus on impact and storytelling, rather than aiming to reflect a true-to-life experience. In virtual reality (VR) environments, where plausibility is favoured over this hyper-real sound design, a question remains on the best ways to recreate realistic, and on the other hand, entertaining inner and imagined voices via head-tracked headphones and spatial audio tools. This paper first presents a questionnaire which has been completed by 70 participants on their own experience of inner voices. Next, the results of the questionnaire are used to inform a VR experiment, whereby different methods to render inner voices are compared. This is conducted using a short film created for this project. Results show that people mostly expect realism from the rendering of inner voices and auditory hallucinations when the focus is on believability. People’s expectations for inner voice did not change considerably in an entertainment context, whereas for hallucinations, exaggerated reverberation was preferred.