Spatial Asynchronous Visuo-Tactile Stimuli Influence Ownership of Virtual Wings

Previous studies revealed that a compelling illusion of virtual body ownership (VBO) might be achieved under a condition of recognizable anatomical and morphological similarities to human body. Though certain deviations from morphology might be acceptable (e.g. virtual tails, longer arm or larger belly), if external limbs are responsible for specific functions in conjunction with a certain virtual scenario. Thus, this study aims at showing a possibility to achieve a compelling VBO illusion over a non-human avatar in a virtual environment. The paper describes a within-subjects study exploring if immersed users could achieve a compelling VBO illusion when inhabiting a virtual body of a bat. Test subjects experienced visuo-tactile stimulation of their arms while seeing an object touching their virtual wings. The mapping between the real and virtual touch points varied across three conditions: no offset between the visual and the tactile input, 50% offset, and 70% offset from the tactile input. The results revealed variations in the degree of experienced VBO across the conditions. The illusion was broken in the absence of visuo-tactile stimulation.