A cross-cultural and experimental investigation of the role of rhythmic stimulation for ritualistically induced altered states of consciousness

Rhythmic stimulation (RS) is commonly believed to be a traditional mechanism for inducing so-called altered states of consciousness (ASCs), during which individuals have non-ordinary experiences of their own bodies, self, or environment. This idea is also applied in psychotherapeutic settings in the form of breathing exercises, singing or rhythmic movement. While ASC induction is a virtually universal aspect of human culture, we know almost nothing about the presence, properties and role of RS in these practices. To move beyond the current state of untested assumptions about the ubiquity and efficacy of RS in ASC we propose a two-pronged approach. We will (1) quantify rhythm and timbre properties in RS used in traditional ASC practices from culturally diverse populations, to test for cross-cultural statistical regularities. We will also (2) conduct experiments based on EEG, EMG, self-report and personality questionnaires aimed at determining which rhythm and/or timbre features are important for ASC effects and to what extent expectations, body- and brain-to-rhythm coupling and certain personality traits influence ASC effects in RS practices. These goals, the integrative methods, and our combined expertise that bridges ASC research and rhythm cognition put us in a unique position to advance the field with empirical data of unprecedented detail and range. The project will, moreover, underscore the relevance of RS and ASCs in the biological and cultural heritage of humans.