Shifting Fall Perception: How Virtual Reality Alters the Precision of Estimating Postural Instability Onset

Perceiving postural instability accurately is crucial for fall prevention. While sensory integration of visual, vestibular, and somatosensory inputs is known to influence balance, the specific impact of high-consequence visual contexts, such as exposure to height, remains under-investigated due to safety constraints in physical environments. This study serves as a proof-of-concept investigation into the use of virtual reality (VR) for manipulating visual context during a postural temporal-order judgement task. In Experiment 1, participants performed the task in real-world conditions (eyes closed and eyes open). Perceived onset of instability was delayed in both conditions (eyes closed: 25.78 ms; eyes open: 12.33 ms), but these did not differ significantly from true simultaneity. Experiment 2 used VR to safely place participants at the edge of a virtual skyscraper. While perceptual delays remained nonsignificant, precision increased significantly in VR (26.89% increase) compared to the real-world eyes-open condition. These results suggest that while the perceived timing of instability is robust, the presence of a high-arousal visual context in VR enhances the precision of multisensory decision-making. As a foundational step in validating VR-based psychophysical balance assessments, these findings demonstrate the feasibility of using virtual environments to study complex sensory motor integration that is difficult to replicate in naturalistic settings.