Anyone who has ever tried to serve a tennis ball or flip a pancake or even play a video game knows, it is hard to perform the same motion over and over again. But don’t beat yourself up—errors resulting from variability in motor function is a feature, not a bug, of our nervous system and play a critical role in learning, research suggests.
Variability in a tennis serve, for example, allows a player to see the effects of changing the toss of the ball, the swing of the racket, or the angle of the serve—all of which may lead to a better performance. But what if you’re serving ace after ace after ace? Variability in this case would not be very helpful.
If variability is good for learning but bad when you want to repeat a successful action, the brain should be able to regulate variability based on recent performance. But how?