Music is a fundamental attribute of the human species. Virtually all cultures, from the most primitive to the most advanced, make music. It's been true through history, and it's true throughout an individual's lifespan. In tune or not, we humans sing and hum; in time or not, we clap and sway; in step or not, we dance and bounce. The human brain and nervous system are hard-wired to distinguish music from noise and to respond to rhythm and repetition, tones and tunes. Is this a biologic accident, or does it serve a purpose? It's not possible to say. Still, a varied group of studies suggests that music may enhance human health and performance.