Whether learning to write, swing a golf club or play the violin, even the most good-natured students become frustrated by inevitable mistakes. Such off-target actions were thought to reflect neural noise in the parts of the brain controlling movement—something a good dose of practice would stamp out. But a new study, published January 12 in Nature Neuroscience, finds that these inconsistencies are not always obstacles to be overcome but rather key ingredients to learning.

Study participants learned to copy a displayed curved line without seeing what their hand was doing. Initially these lines were off the mark for everyone, but some people produced more erratic curves than others did. During training each curve was scored on how well it copied the target curve. All participants gradually produced more accurate curves over hundreds of trials, but those who started out with the most variability before training attained accurate curves more quickly than individuals who began with little irregularity. Another experiment bolstered this link: when researchers promoted variability in one aspect of a movement by applying a force field that pushed the participants' hand off target, they learned the motion faster.

Bigger fluctuations may reflect a brain exploring the full spectrum of possible actions, which would narrow in on accurate movements more quickly than a restricted search. Study author Maurice Smith, a neuroscientist at Harvard University, suggests profiling a person's range of movements after a stroke to aid their rehabilitation. “You could focus training on the types of tasks they are most likely to learn well, as predicted from their variability,” he says. For the rest of us, the results mean we should try not to get frustrated with wild misses when we are learning a new activity. That clumsiness could be the key to quick improvement.