When the beat goes off
Rhythm pulses inside the brain of a Ghanaian drummer, sitting in a physics laboratory in Gottingen, Germany. His hands caress the skin of a bongo drum, guided by the metronome’s tick through his headphones. He plays for five minutes, filling the sterile lab environment with staccato sounds, as a team of physicists records him, searching for a pattern. But the researchers aren’t interested in what he does correctly — they are listening for his errors. Though the drummer is a professional, like all humans, his rhythm is imperfect. Each time his hand hits the drum, his beat falls ahead or behind the metronome by 10 to 20 milliseconds. On average, he anticipates the beat, and plays ahead of it, 16 milliseconds ahead — less than the time it takes a person to blink, or a dragonfly to flap its wings. What the physicists want to know is: Are these errors random,...