Just a heartbeat away from one's body: interoceptive sensitivity predicts malleability of body-representations

TLDR

Body‑awareness depends on integrating interoceptive and exteroceptive signals, but how these systems interact remains unclear. The study aimed to investigate the interaction between interoceptive and exteroceptive body awareness. Interoceptive awareness was measured with a heartbeat‑monitoring task, then a Rubber Hand Illusion was induced and ownership was quantified through behavioural, physiological, and introspective measures. People with lower interoceptive sensitivity experienced a stronger Rubber Hand Illusion, indicating that interoceptive awareness modulates the online integration of multisensory body‑percepts independent of proprioception or autonomic state.

Abstract

Body-awareness relies on the representation of both interoceptive and exteroceptive percepts coming from one's body. However, the exact relationship and possible interaction of interoceptive and exteroceptive systems for body-awareness remain unknown. We sought to understand for the first time, to our knowledge, the interaction between interoceptive and exteroceptive awareness of the body. First, we measured interoceptive awareness with an established heartbeat monitoring task. We, then, used a multi-sensory-induced manipulation of body-ownership (e.g. Rubber Hand Illusion (RHI)) and we quantified the extent to which participants experienced ownership over a foreign body-part using behavioural, physiological and introspective measures. The results suggest that interoceptive sensitivity predicts the malleability of body representations, that is, people with low interoceptive sensitivity experienced a stronger illusion of ownership in the RHI. Importantly, this effect was not simply owing to a poor proprioceptive representation or differences in autonomic states of one's body prior to the multi-sensory stimulation, suggesting that interoceptive awareness modulates the online integration of multi-sensory body-percepts.