Usability, acceptance, and the role of realism in virtual humans for breathing exercise training.

Breathing exercises are used to address a multitude of issues ranging from mental health to physical well-being. While they are recommended for various health conditions, access to professional support is often limited due to time and cost constraints. Virtual Reality technology offers a promising solution for enhancing mindfulness and relaxation practices, including breathing exercises. In our study, we explored the effectiveness of a computer-generated "virtual breathing coach". Our virtual coach has a human appearance, speaks in a human voice, and displays breathing physiology while guiding the participants through a set of breathing exercises of different cycle lengths. The agent exhibits breathing behaviour with the aim of augmenting the influence the agent exerts through the mechanisms of physiological entrainment known from human-to-human interaction. Our empirical, exploratory study with 20 participants, was conducted using non-immersive VR where the system ran on a web browser. On the one hand, we investigated the perception of the virtual human coach, and on the other hand, we evaluated the usability, acceptability, and adherence of the system. We also evaluated the role of realism in acceptance of and adherence to the virtual coach. Participants' responses were recorded using questionnaires. Participants were influenced by the virtual coach and adhered to it if they perceived the virtual coach as more realistic. The participants reported that the system ran well, and they would be willing to continue using the system in the future. Although the virtual human-to-human interaction experience provided by our system is not on par with the naturalistic human-to-human interaction, the results indicate that people are willing to replace a real human coach with a virtual coach. Systems like this are a step towards improving the affordability and on-demand access to another human, such as a coach in our system, especially where access and affordability are limited such as in healthcare. The qualities such as trust and likeability in an embodied interaction can make this interaction more efficient and effective.