Decoding Realism of Virtual Objects: Exploring Behavioral and Ocular Reactions to Inaccurate Interaction Feedback

Achieving temporal synchrony between sensory modalities is crucial for natural perception of object interaction in virtual reality (VR). While subjective questionnaires are currently used to evaluate users' VR experiences, leveraging behavior and psychophysiological responses can provide additional insights. We investigated motion and ocular behavior as discriminators between realistic and unrealistic object interactions. Participants grasped and placed a virtual object while experiencing sensory feedback that either matched their expectations or occurred too early. We also explored visual-only feedback vs. combined visual and haptic feedback. Due to technological limitations, a condition with delayed feedback was added post hoc. . Gaze-based metrics revealed discrimination between high- and low-feedback realism. Increased interaction uncertainty was associated with longer fixations on the avatar hand and temporal shifts in the gaze-action relationship. Our findings enable real-time evaluation of users' perception of realism in interactions. They facilitate the optimization of interaction realism in virtual environments and beyond.