Why practice can't make perfect

Study shows our brains were meant to handle variable, not repetitive, tasks

Ever wonder why your tee shot still slices after smacking 30 buckets of balls on the driving range?

Or why an NBA superstar can still miss a free throw after practising the shot thousands of times?

Well, according to a new study out of Stanford University, a quirk of the human brain ensures that practice can never make perfect.

Human brains have evolved to consider anew even the most practised of motions before launching into them, the study says. And that planning process, often momentary and subconscious, can change the outcome of every move you make.

Our brains ensure that we are "doomed" to make mistakes, says Stanford scientist Krishna Shenoy, whose paper appears this week in the journal Neuron.

Scientists have long believed that the fault for such things as missed shots and errant fastballs lay in the muscles, says Shenoy, an assistant professor in the school's department of electrical engineering and neurosciences program. "The fundamental tenet of the field is ... that you can't activate your muscles the same way every time," he says. "Another fundamental assumption is that your brain can plan that same movement each and every time."

Shenoy's groundbreaking study, however, places at least half the blame on the brain, arguing that its obsessive planning function provides a fertile source for errors.

The failed free throw, for example, is likely foretold seconds before the player's arm is set in motion, as the brain's plan – almost certainly subconscious – has ruined the shot.

"You are doomed to have variability in your movement," says Shenoy. "And it's not just because your muscles can't work perfectly, but also because your brain is incapable, it appears, of planning the same movement each and every time."

source: thestar.com