Effects on Presence, Agency, and Walking in Immersive Virtual Reality of Self-Induced and Estimated Footstep-Sounds

This paper investigates the influence of footstep sounds on the sense of presence, agency, and sensation of walking in immersive virtual reality (VR). Three scenarios were compared: (1) precisely timed footstep sounds triggered by physical steps using in-shoe sensors, (2) footstep sounds estimated based on body-tracked motion, and (3) a baseline scenario without footstep sounds. A within-group design with randomized order was used to compare these scenarios. Results show that accurate footstep sounds significantly enhance presence and agency in immersive VR. However, the scenario with estimated footsteps shows mixed results, with a slight decrease in presence and non-significant effects on agency. The sensation of walking was significantly improved regardless of the sound triggering method. Some users reported a sense of external sources for the steps in the estimated scenario. Participants also reported a shift in spatial focus, with more attention paid to the immediate environment when footsteps were present. These findings underscore the importance of realistic auditory cues to enhance immersion in VR environments.