Why can't we help tapping our feet to music?

We tap our feet to music because hearing a beat switches on the parts of the brain that control movement. Brain scans show that simply listening to music activates regions of the motor system, even when a person is sitting perfectly still. Your brain doesn't just hear the rhythm; it prepares to move with it. Tapping your foot is what happens when that preparation leaks out.

The brain also builds the beat itself. We can feel a steady pulse in a rhythm even when it isn't explicitly played: the brain fills it in and predicts when the next beat will fall. Scientists call this beat induction. It may start remarkably early. When researchers played a simple rock rhythm to babies just two or three days old and occasionally dropped the first beat of the bar, the babies' brains reacted as if an expectation had been broken.

For a long time this skill seemed uniquely human: no primate tested so far can dance or clap along to a beat. Then came Snowball, a cockatoo filmed bobbing his head to the Backstreet Boys. Scientists tested him and found he really did adjust his dancing to the music. One idea is that moving to a beat depends on a tight link between hearing and movement, the same link that lets humans and parrots imitate sounds.