'Embreathment' illusion gauges impact of respiration on embodiment

Combining immersive virtual reality with physiological recordings in a passive observation task, here we describe a new bodily illusion that maps real respiratory patterns onto a virtual body in an ecological fashion. In analogy with terms like embodiment, enfacement, and engazement, we refer to the illusion as ‘embreathment’. The creation of an avatar that breaths in or out of synchrony with our participants allowed us to measure how breathing, one of the most prominent signals coming from within the body, impacts on corporeal awareness - the basic feeling that one has a body (body ownership) which acts according to one’s will (body agency) and which occupies a specific position (body location). In particular, we showed that breathing significantly contributes to the sense of body ownership and body agency. We then ranked breathing against the two fundamental signals that constantly represent the body to the brain, scilicet visual appearance and spatial perspective. The ranking unveiled the hierarchical role of visual, spatial and respiratory signals on different components of corporeal awareness. Furthermore, thanks to the analysis of participants’ performance on a new self-breathing discrimination test, we showed that the effects of both visceral and non-visceral cues on embodiment depend on the ability to perceive visceral signals. These results reveal the crucial role of breathing in self-consciousness and pave the way for a comprehensive model of corporeal awareness.