Visual-haptic integration, action and embodiment in virtual reality.

The current generation of virtual reality (VR) technologies has improved substantially from legacy systems, particularly in the resolution and latency of their visual display. The presentation of haptic cues remains challenging, however, because haptic systems do not generalise well over the range of stimuli (both tactile and proprioceptive) normally present when interacting with objects in the world. This study investigated whether veridical tactile and proprioceptive cues lead to more efficient interaction with a virtual environment. Interaction in the world results in spatial and temporal correlation of tactile, proprioceptive and visual cues. When cues in VR are similarly correlated, observers experience a sense of embodiment and agency of their avatars. We investigated whether sensorimotor performance was mediated by embodiment of the avatar hands. Participants performed a Fitts' tapping task in different conditions (VR with no haptics, active haptics, passive haptics, and on a real touchscreen). The active-haptic condition provided abstract tactile cues and the passive haptic condition provided veridical tactile and proprioceptive cues. An additional (hybrid haptics) condition simulated an ideal passive haptic system. Movement efficiency (throughput) and embodiment were higher for the passive than for the active and no-haptics conditions. However, components of embodiment (perceived agency and ownership) did not predict unique variance in throughput. Improved sensorimotor performance and ratings of presence and realism support the use of passive haptics in VR environments where objects are in known and stable locations, regardless of whether performance was mediated by the sense of embodiment.