Even as practice changes the brain’s anatomy, it also helps different regions of the brain talk to one another. Some neurons strengthen their connections to other neurons and weaken their connections to still others. Early on, neurons in the front of the brain (the prefrontal cortex) are active. That region is vital for top-down control, which enables us to focus on a task and consider a range of responses. With practice, the prefrontal cortex grows quiet. Our predictions get faster and more accurate, so we don’t need so much careful oversight about how to respond.
Several years ago Matthew Smith and Craig Chamberlain of the University of Northern Colorado examined the connection between the quieting of the cortex and athletic ability. They had expert and unskilled soccer players dribble a ball through a slalom course of cones. At the same time, the players were asked to keep an eye on a projector screen on the wall to see when a particular shape appeared. Even with the second task, the seasoned soccer players could dribble at nearly full speed. Unskilled players did much worse than when they were undistracted, however. The disparity suggests that dribbling didn’t tax the expert player’s prefrontal cortex as heavily, leaving it free to deal with other challenges.
As the brains of athletes become more efficient, they learn how to make sense of a new situation sooner. In cricket, for instance, a bowler can hurl a ball at 100 miles an hour, giving batsmen a mere half second to figure out its path. In 2006 Sean Müller, then at the University of Queensland in Australia, and his colleagues ran an experiment to see how well cricket batsmen can anticipate a bowler’s pitch. For their subjects they chose three types of cricket players, ranging in skill from national champions down to university players. The cricketers watched videos of bowlers throwing balls. After each video was over, they had to predict what kind of pitch was coming and where it would land. In some cases the video was cut off at the point at which the bowler released the ball. In other cases the players got to see only the first step, or the first two steps, that the bowler took while the ball was still in his hand.
Elite cricket players did a much better job than less skilled ones at anticipating the outcome of a pitch. They could make fairly good predictions after watching the bowlers take just a single step, and if they got to see the pitch up to the moment of release, their accuracy improved dramatically. The less skilled players fared much worse. Their early guesses were no better than chance, and their predictions improved only if they were able to watch the pitch until the ball had left the bowler’s hand and was in flight.
Predicting the outcome of a task seems to involve the same brain areas that the athlete develops in practice, which would explain why athletes tend to fare better on challenges like these. In a related study, Salvatore Aglioti of Sapienza University assembled a group of people, some of whom were professional basketball players, and scanned their brains as they watched movies of other players taking free throws. Some of the movies stopped before the ball left the player’s hands; others stopped just after the ball’s release. The subjects then had to predict whether it went through the hoop or not. The pros in the group showed a lot of activity in those regions of the brain that control hand and arm muscles, but in the nonathletes those regions were relatively quiet. It seems that the basketball players were mentally reenacting the free throws in their minds, using their expertise to guess how the players in the movies would perform.
These studies are beginning to answer the question of what makes some people great athletes: They are just able to rewire their brains according to certain rules. As neuroscientists decipher those rules, they may find ways to give people better skills. In February 2009 Krakauer and Pablo Celnik of Johns Hopkins offered a glimpse of what those interventions might look like. The scientists had volunteers move a cursor horizontally across a screen by pinching a device called a force transducer between thumb and index finger. The harder each subject squeezed, the faster the cursor moved. Each player was asked to move the cursor back and forth between a series of targets, trying to travel the course as quickly as possible without overshooting. The group trained 45 minutes a day for five days. By the end of training, the players were making far fewer errors.
The scientists also trained another group of people on the same game, but with a twist. They put a battery on top of the head of each subject, sending a small current through the surface of the brain toward a group of neurons in the primary motor cortex. The electric stimulation allowed people to learn the game better. By the end of five days of training, the battery-enhanced players could move the cursor faster and make fewer errors than the control group. And the advantage was not fleeting. For three months Krakauer and Celnik had their subjects come back into the lab from time to time to show off their game-playing skills. Everyone got rusty over time, but at the end of the period, the people who had gotten the electrode boost remained superior to the others.
Krakauer and Celnik’s study hints at a whole new world of ethical issues that may lie ahead for sports. Would it be cheating for a tennis player to wear a portable electrode as she practiced her serve? She would, after all, just be hastening the same changes that come with ordinary practice. Today’s controversies over doping in sports focus mainly on muscles. But tomorrow we may have to decide how much athletes should be allowed to take advantage of neuroscience.