Entrainment in the biomusicological sense refers to the synchronization of organisms to an external rhythm, usually produced by other organisms with whom they interact socially. Have you ever noticed yourself tapping out the rhythm of a song on the radio, even if you don't know or like that song? When I ask my students to chant the sound of om, they will attempt to match the pitch, volume and length of the other voices. If I play music during the pranayama portion of my classes, my students will try to match their breaths to the beat of the music - often without their awareness!
It's believed that this behavior developed as part of a survival mechanism. The ability to be entrained allows humans to fall into the altered state of consciousness called battle trance. In this state, humans lose their individuality, do not feel fear and pain, are united in a shared collective identity, and act in the best interests of the group. This was crucial for the physical survival of our ancestors against the big African predators.
The tribe that entrained was the tribe that survived.
I encourage people going through cancer treatments to come to class as often as they can so they can feel the healing power of their community, of their tribe. Practicing at home is also important, and can be very effective once they have experienced the potency of a class environment.
Now that the predators are more likely to come from within our own bodies, reconnecting with our tribe is vital. We don't have to be physically present. We don't have to be exactly alike. We just have to recognize our similarities and entrain to that calming rhythm.
Reluctant or not, our tribes will save us.