Dancing in the Streets, sociology book

Barbara Ehrenreich's ideas about group bonding struck a chord. She quotes dozens of articles: psychology, sociology, paleontology, etc.
Robin Dunbar, speaking about prehistoric man, suggests 150 is an optimal size for a group, seeing language as subservient to danced rituals. I like that number, too.
Entrainment comes in, synchronizing and reciporcating, according to Marcel Kinsbourne, "Marching, chanting, dancing - may trigger a primitive sense of irrational and beguiling belonging and a shared mindset." Forming groups was key to primitive man's success.
A neuroscientist (no name) calls dance "the biotechnology of group formation."
A psychologist, Osterreich, says, "Dancing is contagious; humans experience strong desires to synchronize theri own bodies' motions with those of others. The stimuli, which can be auditory or visual or derived from an internal sense of one's own muscular response to the rhythm can drive cortical rhythms and eventually produce an intensely pleasurable ineffable experience in humans." A bit wordy.

Then a chapter about dance as a way of choosing a sexual partner. Not a new idea.
As religions formed, the god of ecstasy, Dionysus, had female worshippers who went into frenzies. Yahweh's followers were constantly being exhorted to leave Baal behind.
Finally, she visits Brazil and observes a samba school, over 150 people, practicing for carnaval.  Bystanders joined in for a momentary festival. " No embarassment, no alcohol, no 'point', no religion, no message, no money. The chance to acknowledge the miracle of out simultaneous existence with some sort of celebration."