Investigating the Impact of Customized Avatars and the Proteus Effect during Physical Exercise in Virtual Reality

Research Background and Issues

• Issues and Challenges: The authors observe that while using avatars in virtual reality (VR) can enhance user behavior and experience during physical activities, the visual characteristics of avatars (e.g., body physique) do not always improve performance or reduce psychophysiological load as expected. This is particularly true when users lack a sense of body ownership illusion (BOI) or identification with the avatar. In such cases, the positive effects of avatars on physical activity may not materialize. Furthermore, there is limited research on whether highly personalized avatars can amplify the Proteus effect, which remains a critical unknown.

• Significance: Body ownership and identification are key factors in realizing the behavioral effects of avatars. Exploring how avatar customization can enhance the Proteus effect and improve the experience of physical activities can aid in developing more efficient and user-friendly VR fitness applications, thereby promoting public engagement and adherence to physical exercise.

• Research Motivation and Related Work: Studies on the Proteus effect have demonstrated that avatar appearance can significantly influence user behavior and psychology, such as muscular avatars reducing perceived exercise intensity. However, these effects may disappear when avatar identification or body ownership is lacking. Personalized avatars have been suggested to improve identification, but their specific impact on the Proteus effect remains unclear.

Solution

• Methods and Approach: The authors propose designing a feature-rich VR avatar customization editor that allows users to create avatars matching their appearance and physical traits in a virtual environment, thereby enhancing avatar identification and body ownership. Users can customize two avatars representing "one year of healthy exercise" and "one year of unhealthy sedentary lifestyle."

• Innovations:

  • Customization Tool: Development of an interactive VR avatar customization editor enabling users to experience avatars in a first-person perspective and adjust features such as appearance, body shape, clothing, and colors in real time.
  • Experimental Design: Comparison of non-customized avatars and customized avatars in terms of physical performance and psychological and physiological responses, systematically disentangling the interaction effects between avatar customization levels and physical activity capabilities.
  • Task Selection: Design of diverse experimental tasks (e.g., isometric exercises, dynamic movements) to cover varying physical demands and explore task dependency of the Proteus effect.

• Implementation Steps and Key Technologies:

  • Technical Support: Use of the OptiTrack motion capture system to synchronize user movements with avatars, and development of the avatar editor using the Unity engine.
  • Experimental Design: Conduct repeated measures experiments comparing four avatar combinations (randomly assigned healthy and unhealthy avatars, and two user-customized avatars) in terms of perceived effort, heart rate, and physical performance.
  • Control Variables: Balance the order of experimental tasks, ensure consistent task intensity, and monitor potential fatigue accumulation effects.

Research Outcomes

• Specific Results:

  • Perceived Effort: Customized avatars and healthy avatars significantly reduced participants' perceived difficulty during weightlifting tasks.
  • Heart Rate Impact: Results indicate that the interaction between healthy avatar attributes and customization significantly lowered heart rate responses (observed only in isometric exercise tasks).
  • Physical Performance: During dynamic tasks (e.g., bicep curls), customized avatars improved physical performance.

• Advantages Compared to Existing Solutions:

  • Enhanced regulation of perceived effort and heart rate: Findings show that personalized avatar customization strengthens the psychological and physiological responses of the Proteus effect.
  • Differentiation of task types and avatar effects: The study reveals task dependency of the Proteus effect, making avatar design more targeted.

• Experimental or Evaluation Results:

  • Control Group Comparison: Randomly assigned avatars showed significantly lower scores in body ownership and identification compared to customized avatars.
  • Data Analysis: The interaction between customization and healthy avatar attributes significantly reduced heart rate during weightlifting, but similar effects were not observed in other tasks.
  • Correlation Analysis: Self-assessed physical health negatively correlated with perceived exercise effort and heart rate.

• Limitations and Future Directions:

  • Limitations: The customization options for virtual avatars are not comprehensive enough to cover all design dimensions that may affect identification and body ownership; the study does not address long-term behavioral impacts.
  • Future Research Directions:
    • Investigate the long-term effects of avatar use on behavior and physical activity sustainability.
    • Enhance customization flexibility, such as creating avatars more closely resembling users' real appearance through scanning technologies.
    • Analyze the generalizability of the Proteus effect across different types of physical activities to inform best practices for task design and avatar presentation.

In summary, this study not only reveals the regulatory effects of customized avatars on psychological and physiological responses but also expands the application of the Proteus effect across various exercise scenarios, advancing the theoretical and practical foundation for designing virtual fitness applications.