Understanding how speed affects performance of polyrhythms: transferring control as speed increases.

Pianists (N = 9) memorized and performed polyrhythms over a range of speeds from 1 to 16 notes/s. Using several fingers of each hand to press the keys on a piano keyboard, they performed the 5:3 polyrhythm by playing "3s" with one hand simultaneously with "5s" in the other. All the participants were able to maintain overall tempos and rhythms to within 10% of target speeds despite increasing difficulty. Increasing speed led to a transfer of control at about 6 notes/s, with a modular system operating above that speed. The participants were also able to engage in timing coupling at all speeds, even when the hands belonged to different people.