Artificial hand illusions dynamics: Onset and fading of static rubber and virtual moving hand illusions

The aim of this study was to investigate the temporal dynamics of two multisensory body illusions: a static rubber hand illusion (RHI) and a moving virtual hand illusion (VHI). We explored the onset and fading of these illusions. A sense of ownership questionnaire and proprioceptive drift were used for illusion estimation. Novel kinematic analysis was applied for the VHI. Positive dynamics of ownership were found in the RHI but not in the VHI. The general dynamics of proprioceptive drift were similar in both illusions: during the onset phase of artificial hand representation proprioceptive drift gradually increased, and during the fading phase - it gradually decreased. Kinematic analysis of the VHI revealed several motion features (such as jerk, smoothness, velocity), predicted illusion measures, and probably reflected that participants with higher motor abilities and better adaptation to new sensory conditions may have better multisensory integration mechanisms that are responsible for the ownership illusion.