The beat drops — and people start nodding their heads.
It's a common behavior, so it's easy to disregard. But the reasons why humans respond to a thumping bass line so strongly aren't necessarily obvious. Some scientists have observed that the human brain is much more attuned to low-frequency sounds, compared with high-frequency sounds. Other researchers have demonstrated that the sounds that a fetus hears in the womb — a mother's heartbeat, for instance — affect brain development in important ways. Whatever the mechanism behind this may be, however, it's clear that human culture is deeply rooted in rhythm.