Impact of Threshold-Relative Curvature Gains on Cognitive Cost: A Pilot Study
We conducted a pilot study comparing a no-redirection baseline against three redirected-walking conditions calibrated relative to participants' detection thresholds, to examine how the noticeability of redirection affects performance on a concurrent memory task.
Redirected Walking (RDW) enables natural locomotion in limited virtual spaces through subtle perceptual manipulations, but it can introduce additional cognitive demands. While redirection is intended to remain imperceptible, individual responses to this manipulation vary. This tolerable deviation between the visual and vestibular systems is known as the detection threshold. It remains unclear how noticeability at different levels relative to this threshold affects cognitive task performance. To address this gap, this pilot study utilises a dual-task paradigm where participants navigate a virtual labyrinth while performing an auditory 2-back memory task. Curvature gains are applied across four conditions derived from a group-level psychometric curve: no redirection, under threshold, on threshold, and over threshold. This research aims to understand how these manipulations draw on cognitive resources and how RDW can be applied to maintain cognitive performance.
Overview
The study focuses on the following core principles and areas of investigation:
- Threshold Identification: Establishing group-level psychometric curves to precisely map the noticeable limits of curvature gains.
- Cognitive Impact Assessment: Evaluating how different levels of redirection intensity interact with human working memory and spatial cognition.
- Navigation Complexity: Moving beyond traditional straight-line walking tests by evaluating dual-task performance inside a virtual labyrinth.
- User Experience Optimization: Tracking the subjective comfort, cybersickness, and behavioral impacts of physical resets during locomotion.
Research Methodology
The pilot study was conducted across distinct methodological stages to map user perception before testing multi-task performance. The project structure consists of:
- Detection Threshold Task: A baseline session where participants walked toward a virtual target to calculate a group-level psychometric curve across six distinct curvature gain levels.
- Dual-Task Cognitive Evaluation: A secondary session combining complex labyrinth navigation with an auditory 2-back memory task to assess cognitive load at four threshold-related conditions.
- Subjective and Feedback Analysis: Evaluation of perceived mental effort (Paas scale), cybersickness data (CSQ-VR), and qualitative user feedback regarding physical constraints.
Key Results
The study yielded several critical insights regarding the relationship between redirection visibility and mental task performance:
- Poorer Performance Below Threshold: Task accuracy in the 2-back memory task significantly decreased and the false alarm rate significantly increased specifically in the “Under Threshold” (UT) condition compared to the baseline (No Redirection).
- Cognitive Compensation: Performance did not continue to decline at higher, more noticeable gain levels (On/Over Threshold), suggesting users might cognitively adapt or compensate when the manipulation becomes perceptible.
- Reset Interference: While physical reset rates (stopping to turn on the spot when hitting a physical tracking boundary) did not statistically alter performance metrics, qualitative feedback revealed that resets were heavily disruptive, distracting, and caused increased dizziness.