Psychological Effects of Rhythmic Entrainment and Trance Experience: A Review

Abstract

Synchronization to music is a basic ability for humans and the key component of synchronization is to entrain a particular rhythm. EEG studies show that when we synchronize with a rhythm, our brain waves also synchronize. From this view, trance can be a state of consciousness that is a result of rhythmic entrainment of brain waves. It is known that Shamans perform a ceremony with drums and experience trance for centuries. Although using rhythm to mediate trance goes back to Shamanism, it is also a part of different cultures. Trance experience continues its existence with psychedelic trance dance in the West and also with dhikr and Sama in the East world. If we define the term of “trance” as “a state of wajd”, experiences of Shaman rituals, psychedelic dance and dhikr are similar, because of using rhythm as a mediator. In this review, comparison of the trance experiences shows that the psychological effects of rhythmic entrainment point to a fundamental mechanism beyond cultural differences.