Dissociable Spatial and Temporal Effects of Interaction Latency in Virtual Reality
Motion-to-photon latency is inherent in immersive virtual reality (VR) systems and can arise from multiple sensorimotor loops, including view-contingent latency between head movement and display update and interaction latency between hand movement and the virtual effector. Although prior work shows that interaction latency can impair VR performance, it remains unclear whether common spatial, temporal, and efficiency measures reveal the same latency-related disruption. This study addressed this question by experimentally imposing delays between the physical and virtual hands during manual pointing in VR. Participants pointed to targets on a horizontal surface in VR and in the physical environment as an unmediated baseline. In VR, pointing was performed with a virtual hand avatar controlled by a motion capture pipeline, and additional delays (0-500 ms) were imposed between the participant's hand movement and the rendered movement of the virtual hand. Relative to the baseline, performance in VR showed greater endpoint error, longer movement time, greater endpoint variability, and lower throughput. Within VR, added interaction latency further increased endpoint error and variability, reduced throughput, and altered movement time, but these effects followed different profiles: endpoint error increased even at the shortest delays, whereas movement time remained stable at short delays and increased primarily at longer delays. These findings show that interaction latency produces dissociable spatial and temporal consequences in immersive VR, such that endpoint accuracy revealed disruption before movement time or throughput. Thus, latency-sensitive VR interactions cannot be fully evaluated using movement time or efficiency measures alone. Instead, HCI evaluations should assess both spatial and temporal performance, particularly when VR tasks involve visually guided manual actions.