On the role of visceral physiological signals in corporeal awareness

Our body is the only object we sense from the inside; however, existing literature has largely left unanswered the question of how much inner physiology contributes to the global sensation of having a body and controlling it. The five experiments described in the present thesis were planned and executed with the goal of filling this gap of knowledge and provide empirical insights into the visceral roots of corporeal awareness. Results indicate that the contribution of inner physiological signals to corporeal, emotional and moral awareness is substantive, specific, and subjective. • Substantive: breathing contributes to perceived body ownership almost as much as visual appearance (expt. 1), while stomach activity not only predicts body ownership (expt. 2) but also the conscious perception of disgust and sadness (expt. 3) and moral disgust (expt. 4). • Specific: respiration impacts only on perceived body ownership and agency (expt. 1); the activity of the stomach, as mapped by EGG, had a selective effect on the sense of body ownership, while it did not influence the ratings of perceived body location and agency (expt. 2); the gastric effects on emotional awareness are specific for disgust and sadness (expt. 3), while the gastric signature of first-person moral judgments is different from that of third-person moral judgments (expt. 4). • Subjective: individual levels of interoceptive accuracy and sensibility predict the strength of the embreathment illusion (expt. 1), while interoceptive deficits caused by individual features like the expression of a single gene (PIEZO2) seem to be associated with an impaired sense of one’s own body (expt. 5).