ShareYourReality: Investigating Haptic Feedback and Agency in Virtual Avatar Co-embodiment

Document Title

ShareYourReality: Investigating Haptic Feedback and Agency in Virtual Avatar Co-embodiment

Document Information

• Subject Area: Virtual Reality, Human-Computer Interaction (HCI), Haptic Feedback, Virtual Avatar Co-embodiment
• Keywords: Virtual Reality, Virtual Avatar Co-embodiment, Haptic Feedback, Sense of Agency (SoA), Body Ownership, Co-presence, Perceptual Crossing

Research Background and Issues

• Identified Issues:

  • Virtual Reality (VR) enables collaborative interaction among multiple users; however, conventional implementations typically assign each user a separate avatar, which may not fully leverage the potential for social interaction.
  • "Virtual Avatar Co-embodiment," where two users share a single avatar, can enhance social coordination and interaction effectiveness. However, the sense of agency is often affected by the shared control mechanism in this mode.
  • Current research faces challenges in effectively supporting non-verbal coordination among users in co-embodiment scenarios, particularly lacking in-depth exploration of the application and impact of haptic feedback within such mechanisms.

• Importance of the Research:

  • Virtual Avatar Co-embodiment holds significant potential in fields such as rehabilitation medicine (e.g., stroke recovery, dementia management), motor skill training, and social education.
  • Effective and precise feedback mechanisms are crucial for enhancing immersion and task completion efficiency in multi-user shared control scenarios.

• Motivation and Related Work:

  • Inspired by the concept of Perceptual Crossing, haptic feedback is considered an ideal method for supporting non-verbal interaction between users.
  • While existing studies have explored haptic feedback in non-shared or simple shared avatar contexts, there is a lack of research specifically targeting complex co-embodiment scenarios.

Solution

• Proposed Methods or Solutions:

  • Introduce location-sensitive haptic feedback to enhance non-verbal coordination between users in co-embodiment scenarios.
  • Implement a haptic feedback mechanism that triggers vibration cues only when users' hand movements overlap in the virtual space.
  • Investigate the effects of different avatar control distributions (e.g., 50%-50%, 25%-75%) and two task environments (goal-oriented tasks and free-choice tasks) on user perception.

• Innovations:

  • Apply the Perceptual Crossing paradigm to the domain of virtual avatar co-embodiment, enabling in-depth research on non-verbal communication and motor interaction through haptic feedback.
  • Provide empirical insights into how haptic feedback influences sense of agency, co-presence, body ownership, and movement synchronization.

• Implementation Steps and Techniques:

  • Adopt a within-subject experimental design, including haptic feedback conditions (on/off) and control allocation ratios (25%-75%, 50%-50%, 75%-25%).
  • Utilize Oculus Quest 2 touch controllers and virtual environments to ensure real-time motion tracking and data recording.
  • Collect subjective questionnaire feedback (sense of agency, co-presence, body ownership) and objective motion behavior data (e.g., hand movement synchronization).

Research Outcomes

• Specific Findings:

  1. Sense of Agency (SoA): Users reported higher sense of agency in goal-oriented tasks, while lower sense of agency was reported in free-choice tasks with haptic feedback.
  2. Co-presence: Co-presence was significantly higher in free-choice tasks compared to goal-oriented tasks, possibly due to the active user coordination required by the task.
  3. Body Ownership: Users experienced greater influence of virtual hand movements on their real hand movements in free-choice tasks.
  4. Hand Movement Synchronization: Hand movement synchronization was higher in goal-oriented tasks compared to free-choice tasks.

• Advantages Over Existing Solutions:

  • This study highlights the critical impact of haptic feedback (e.g., vibration signals) on user interaction and perception, offering a mechanism to enhance non-verbal collaboration among users.
  • It supplements existing research on avatar control and feedback mechanism design in complex co-embodiment scenarios.

• Experimental or Evaluation Results:

  • Users showed higher acceptance of shared avatars in goal-oriented tasks, while enhanced coordination behaviors in free-choice tasks improved co-presence.
  • However, haptic feedback was perceived as intrusive in certain situations, negatively affecting the sense of agency.

• Limitations and Future Directions:

  • The study only covers limited haptic feedback modes (simple vibration on/off) and basic hand control scenarios.
  • There is a lack of exploration regarding the combined effects of multimodal feedback (e.g., visual and haptic) in co-embodiment environments.
  • Further investigation is needed into the long-term effects of haptic feedback and user responses across different cultural contexts.

This research reveals the potential complexity of haptic feedback and the diverse user perceptions it entails, providing theoretical guidance for designing more inclusive and efficient mechanisms in future virtual avatar co-embodiment applications.