“The Dance of Life: The Other Dimension of Time” by Edward T. Hall studies “how people are tied together and yet isolated by hidden threads of rhythm and walls of time.” It contains this fascinating passage describing how humans sync up with each other:

Rhythm is basic to synchrony. This principle is illustrated by a film of children on a playground. Who would think that widely scattered groups of children in a school playground could be in sync. Yet this is precisely the case. One of my students selected as a project an exercise in what can be learned from film. Hiding in an abandoned automobile, which he used as a blind, he filmed children in an adjacent school yard during recess. As he viewed the film, his first impression was the obvious one: a film of children playing in different parts of the school playground. Then — watching the film several times at different speeds, he began to notice one very active little girl who seemed to stand out from the rest. She was all over the place. Concentrating on the girl, my student noticed that whenever she was near a cluster of children the members of that group were in sync not only with each other but with her. Many viewings later, he realized that this girl, with her skipping and dancing and twirling, was actually orchestrating movements of the entire playground! There was something about the pattern of movement which translated into a beat — like a silent movie of people dancing. Furthermore, the beat of this playground was familiar! There was a rhythm he had encountered before. He went to a friend who was a rock music aficionado, and the two of them began to search for the beat. It wasn’t long until the friend reached out to a nearby shelf, took down a cassette and slipped it into a tape deck. That was it! It took a while to synchronize the beginning of the film with the recording — a piece of contemporary rock music — but once started, the entire three and a half minutes of the film clip stayed in sync with the taped music! Not a beat or a frame of the film was out of sync!

...When he showed his film to our seminar, however, even though his explanation of what he had done was perfectly lucid, the members of the seminar had difficulty understanding what had actually happened. One school superintendent spoke of the children as “dancing to the music”; another wanted to know if the children were “humming the tune.” They were voicing the commonly held belief that music is something that is “made up” by a composer, who then passes on “his creation” to others, who, in turn, diffuse it to the larger society. The children were moving, but as with the symphony orchestra, some participants’ parts were at times silent. Eventually all participated and all stayed in sync, but the music was in them. They brought it with them to the playground as a part of shared culture. They had been doing that sort of thing all their lives, beginning with the time they synchronized their movements to their mother’s voice even before they were born.

Related: “Sync” by Steven Strogatz explores “the mysterious synchrony achieved by fireflies that flash in unison by the thousands, and the question of what makes our own body clocks synchronize with night and day and even with one another…The author traces how the isolated and often accidental discoveries of researchers are beginning to gel into the science of synchrony, and he amply illustrates how the laws of mathematics underlie the universe’s uncanny capacity for spontaneous order.” Here’s a review of the book and an interview with Strogatz.