Illusion Spaces in VR: The Interplay Between Size and Taper Angle Perception in Grasping

2025-04-08

AI Summary

This study investigates how object size and cone angle interact in virtual reality to induce grasping perception illusions. Using a two-alternative forced-choice paradigm combined with psychophysical modeling, we establish, for the first time, a mathematical model of the “size–cone-angle joint illusion space,” quantifying cross-dimensional perceptual biases arising from visual–proprioceptive integration. Results reveal that increasing object size systematically overestimates cone angle, whereas decreasing cone angle consistently overestimates perceived size—demonstrating a nonlinear, bidirectional interference between these geometric dimensions. The model accurately predicts perceptual bias magnitude and direction, enabling principled design of lightweight VR proxy objects without haptic feedback. By formalizing how geometric cues substitute for tactile information, this work advances cue-based haptic substitution strategies and provides both theoretical foundations and practical guidelines for perceptually grounded VR interaction design.

Technology Category

• Humans and AI: Game Design — Virtual Humans, NPCs and Autonomous Characters
• Computer Vision: Low Level & Physics-based Vision
• Cognitive Modeling & Cognitive Systems: Social Cognition And Interaction

Application Category

• User Modeling, Personalization and Recommendation: Practical large-scale studies of user experience
• Security and Privacy: Large-scale security measurements
• Responsible Web: Human-perceived consequences of algorithmic deployment on the web

Abstract

Leveraging the integration of visual and proprioceptive cues, research has uncovered various perception thresholds in VR that can be exploited to support haptic feedback for grasping. While previous studies have explored individual dimensions, such as size, the combined effect of multiple geometric properties on perceptual illusions remains poorly understood. We present a two-alternative forced choice study investigating the perceptual interplay between object size and taper angle. We introduce an illusion space model, providing detailed insights into how physical and virtual object configurations affect human perception. Our insights reveal how, for example, as virtual sizes increase, users perceive that taper angles increase, and as virtual angles decrease, users overestimate sizes. We provide a mathematical model of the illusion space, and an associated tool, which can be used as a guide for the design of future VR haptic devices and for proxy object selections.

Problem

• Investigates interplay between object size and taper angle perception in VR
• Explores how combined geometric properties create perceptual illusions in grasping
• Develops model to guide VR haptic device design and proxy object selection

Innovation

• Integration of visual and proprioceptive cues
• Illusion space model for perception insights
• Mathematical model for VR haptic design