The brain can get by on less energy when you overlearn a task
“Why do I have to keep practicing? I know it already!” That’s the
familiar wail of a child seated at the piano or in front of the multiplication
table (or, for that matter, of an adult taking a tennis lesson). Cognitive
science has a persuasive retort: We don’t just need to learn a task in order to
perform it well; we need to overlearn it. Decades of research have shown
that superior performance requires practicing beyond the point of
mastery. The perfect execution of a piano sonata or a tennis serve doesn’t mark
the end of practice; it signals that the crucial part of the session is just
getting underway.
(MORE: 10,000 Hours May Not Make a Master After
All)
Evidence of why this is so was provided by a study published recently
in the Journal of Neuroscience. Assistant professor Alaa Ahmed and two of
her colleagues in the integrative physiology department at the University of
Colorado-Boulder asked study subjects to move a cursor on a screen by
manipulating a robotic arm. As they did so, the researchers measured the
participants’ energy expenditure by analyzing how much oxygen they inhaled and
how much carbon dioxide they breathed out. When the subjects first tackled the
exercise, they used up a lot of metabolic power, but this decreased as their
skill improved. By the end of the learning process, the amount of effort they
expended to carry out the task had declined about 20 percent from when they
started.
Whenever we learn to make a new movement, Ahmed explains, we form and then
update an internal model—a “sensorimotor map”—which our nervous system uses to
predict our muscles’ motions and the resistance they will encounter. As that
internal model is refined over time, we’re able to cut down on unnecessary
movements and eliminate wasted energy.
Over the course of a practice session, the subjects in Ahmed’s study were
becoming more efficient in their muscle activity. But that wasn’t the whole
story. Energy expenditures continued to decrease even after the decline in
muscle activity had stabilized. In fact, Ahmed and her coauthors report, this is
when the greatest reductions in metabolic power were observed—during the very
time when it looks to an observer, and to the participant herself, as if
“nothing is happening.”
(MORE: Ten Ways We Get Smarter As We
Age)
What’s going on here? Ahmed theorizes that even after participants had
fine-tuned their muscle movements, the neural processes controlling the
movements continued to grow more efficient. The brain uses up energy, too, and
through overlearning it can get by on less. These gains in mental efficiency
free up resources for other tasks: infusing the music you’re playing with
greater emotion and passion, for example, or keeping closer track of your
opponent’s moves on the other side of the tennis court. Less effort in one
domain means more energy available to others.
While Ahmed’s paper didn’t address the application of overlearning to the
classroom or the workplace, other studies have demonstrated that for a wide
range of academic and professional activities, overlearning reduces the amount
of mental effort required, leading to better performance—especially under
high-stakes conditions. In fact, research on the “audience
effect” shows that once we’ve overlearned a complex task, we
actually perform it better when other people are watching. When we
haven’t achieved the reduction of mental effort that comes with overlearning,
however, the additional stress of an audience makes stumbles more likely.
“The message from this study is that in order to perform with less effort,
keep on practicing, even after it seems the task has been learned,” says Ahmed.
“We have shown there is an advantage to continued practice beyond any visible
changes in performance.” In other words: You’re getting better and better, even
when you can’t tell you’re improving—a thought to keep you going through those
long hours of practice.
This article is from the Brilliant Report, a weekly
newsletter written by Annie Murphy Paul.
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