Rhythmicity and Trait Absorption Are Linked to Nonordinary States of Consciousness

A widely observed phenomenon across cultures involves the use of rhythmic auditory stimulation in intricate rituals to achieve dissociative mental states. While several physiological mechanisms link repetitive auditory stimuli to nonordinary states of consciousness (NSCs), entrainment-the brainwave synchronization through periodic external stimuli-has received particular attention. However, there is limited experimental evidence on this relationship, and the influence of certain personality traits that shape the strength of NSCs remains underexplored. In our study, 27 participants with no prior experience of rhythm-induced NSCs listened to 12 min of both rhythmic and nonrhythmic drum sounds. Following each type of stimulation, they engaged in cognitive tasks and reported their phenomenological experiences related to NSCs through questionnaires. Electroencephalography was employed to record brain activity, evaluating whether entrainment to the drum sounds affected both objective and subjective proxies of NSCs. Our findings show that higher trait absorption was associated with stronger experiences of disembodiment and spirituality during drumming listening. Also, rhythmic drum sounds increased experiences of unity compared to nonrhythmic ones, and for individuals with low trait absorption, it also increased spiritual experiences. These findings suggest that rhythm influences the characteristics of the resulting phenomenological experience.