Exploring Sensory Conflict Effect Due to Upright Redirection While Using VR in Reclining & Lying Positions

Title of the Paper

Exploring Sensory Conflict Effect Due to Upright Redirection While Using VR in Reclining & Lying Positions

Paper Information

• Subject Area: Sensory conflict and redirection techniques in Virtual Reality (VR)
• Keywords: Virtual Reality, reclining and lying positions, redirection techniques, upright illusion, sensory conflict

Research Background and Problem

• Problem or Challenge:

  • Traditional VR design primarily targets standing or seated postures, but an increasing number of users are using VR in reclining or lying positions, which require upright redirection of the viewpoint to enhance user experience.
  • Upright redirection may trigger conflicts between visual, vestibular, and proprioceptive sensations, affecting users' sense of body ownership, presence, simulation sickness, and spatial perception.
  • Vestibular sensitivity dynamically adjusts with changes in body recline angles, and a quantitative evaluation of the impact of upright redirection on user perception remains unresolved.

• Significance:

  • A deeper understanding of multisensory integration and sensory conflict's impact on VR experiences is crucial for improving VR design, especially for non-traditional usage postures like reclining or lying down.

• Related Work:

  • Previous studies have largely focused on redirection, scaling, and target mapping techniques in VR, typically for movement and interaction, with limited exploration of sensory conflict in reclining and lying positions.
  • Current perception research mainly investigates dynamic weighting based on vestibular and visual sensory integration but lacks comprehensive evaluation of upright redirection's overall impact.

Solution

• Research Methods:

  • This study conducts upright redirection experiments on users at five different body recline angles (0°, 22.5°, 45°, 67.5°, and 90°).
  • Three sub-studies are conducted to evaluate: the impact of upright redirection on intrinsic self-perception (Study 1), its effect on spatial perception (Study 2), and the feasibility of improving perception outcomes through enhanced methods (Study 3).

• Innovations:

  • Systematically quantifies the impact of upright redirection on sensory disturbances, while providing psychological and physiological explanations for the findings.
  • Proposes and preliminarily validates illusion-enhancing and sensory-matching methods to alleviate discomfort caused by sensory conflicts.

• Implementation Steps and Techniques:

  1. Experimental Design:
     • Create virtual environments, including static observation tasks and motion tasks, to simulate user perception at different recline angles.
     • Design four spatial perception tasks (line adjustment, distance perception, direction perception, position perception) to study perceptual biases.
  2. User Study:
     • Use Oculus Quest 2 to analyze participants' subjective evaluations (e.g., body ownership scale, presence scale, and simulation sickness questionnaire).
     • Analyze dependent variables using Friedman tests and grouped comparison statistical methods.
  3. Improvement Methods:
     • Design four improvement strategies: dynamic upright redirection, head rotation correction, uniform motion simulation, and visual-proprioceptive matching.

Research Findings

• Specific Results:

  • Both experiments showed that increasing recline angles intensified sensory conflicts, but at extreme angles (e.g., 90°), sensory conflicts were alleviated due to reduced vestibular sensitivity.
  • The 45° angle resulted in the poorest interaction experience, with users reporting the highest levels of simulation sickness and spatial cognitive bias.
  • The proposed improvement methods (e.g., dynamic upright redirection) demonstrated positive effects in mitigating sensory conflicts.

• Advantages:

  • Provides profound insights into the dynamic weighting process of multisensory integration and validates the potential of sensory matching and weight adjustment in mitigating conflicts.
  • The proposed strategies showed significant improvements in both self-perception (body ownership, presence) and external spatial perception (position, line adjustment).

• Limitations and Future Directions:

  • The small sample size used in the study (e.g., only 14 participants in Study 3) limits the generalizability of the statistical conclusions.
  • Current improvement methods require external auxiliary devices, which limit their convenience.
  • Future research should explore additional optimization methods and validate their generalizability across other angles (e.g., 22.5° or 67.5°) and more diverse stimulation conditions.
  • Further integration with neuroscience experiments is needed to conduct a deeper analysis of the neural basis of dynamic sensory weighting mechanisms.

Conclusion

This study thoroughly investigates the sensory conflict issues caused by upright redirection in VR for reclining and lying positions. Through experiments, it validates several methods for mitigating sensory conflicts, offering new insights for enhancing VR immersion, particularly in interaction design for non-traditional postures.