Temporal dynamics of full-body ownership and vicarious touch sensations as inferred from embodying a virtual avatar.

Feeling a tactile sensation when observing a touch on an artificial body (Vicarious Touch, VT) and the illusion of full-body ownership (Full-body Ownership Illusion, FBOI) can be effectively induced using Virtual Reality (VR). However, the onset timing of these phenomena, particularly under visual-only stimulation, remains elusive. While prior research has focused on body-part ownership under visuotactile conditions, the temporal dynamics of VT in a full-body context remain underexplored. This study investigated FBOI and VT in 34 healthy participants observing a virtual body from either a first-person (1PP) or third-person (3PP) perspective. Illusory experiences were categorized into different outcomes, and participants provided subjective ratings of onset timing and intensity. These were analyzed alongside physiological measures (respiratory rate, heart rate variability, and skin conductance) and psychological traits (empathy and attachment) to explore factors modulating these experiences. Results showed that 1PP significantly accelerated and intensified both FBOI and VT, highlighting the pivotal role of perspective in sensory integration. Conversely, 3PP was linked to a higher prevalence of No Illusion outcomes and weaker illusions, reflecting difficulties in aligning sensory cues. Respiratory rate emerged as a marker of VT experiences, while empathy predicted faster and more intense VT, indicating greater sensitivity in emotionally attuned individuals. These findings provide insights into the temporal dynamics of VT and FBOI, with implications for VR-based therapeutic applications targeting sensory integration and body representation.