Understanding individual differences in non-ordinary state of consciousness: Relationship between phenomenological...

Non-ordinary states of consciousness offer a unique opportunity to explore the interplay between phenomenological experiences and physiological processes. This study investigated individual differences in phenomenological and autonomic nervous system changes between a resting state condition and a non-ordinary state of consciousness (auto-induced cognitive trance, AICT). Specifically, it examined the relationship between self-reported experiences (e.g., absorption, visual representations) and heart rate variability (HRV). Twenty-seven participants underwent electrocardiography recordings and completed self-report questionnaires during rest and AICT. A machine learning framework distinguished the rest and AICT states based on self-reported measures and HRV metrics. A linear mixed-effects model assessed inter-individual differences in HRV and self-reported phenomenology between the two states. Finally, the relationship between relative change in HRV and self-reported experiences was explored. Results showed changes in self-reported phenomenology (accuracy=86 %; p<.001) and HRV (accuracy=73 %; p<.001) characterizing the AICT state compared to rest. The baseline level in phenomenology or HRV was associated with change amplitude during AICT. Moreover, relative change in HRV was associated with change in phenomenology. The findings suggest that inter-individual differences at rest revealed a functional mechanism between phenomenology and the autonomic nervous system during non-ordinary states of consciousness, offering a novel perspective on how physiological mechanisms shape subjective experiences.