CHAPTER 4
THE HOMUNCULUS IN THE GAME
or, When Thinking Is as Good as Doing
In the early 1980s the sports world was seduced by a new set of ideas for how to juice up physical performance. With the help of audio and video tapes, athletes could learn how to relax, set goals, solve problems, assert themselves, concentrate, induce self-hypnosis, and rehearse their skills. By engaging in what was loosely called “mental training,” they could throw farther, leap higher, skate faster, sink more of their shots, and otherwise perform much better in their chosen sport. It became a major trend. For example, more than half of the finalists and two-thirds of the medal winners for the 1980 Swedish Olympic team had used mental training.
And yet, according to William Straub, a now-retired sports psychologist at Ithaca College, many of the claims of mental training’s efficacy were anecdotal. And mental practice is a broad rubric, a mishmash of techniques. While many coaches and athletes believe that relaxation, visualization, and imagery enhance physical performance, they have a glut of programs to choose from: symbolic rehearsal, modeling, covert practice, cognitive rehearsal, imaginal practice, dream work, hallucination, hypnosis, visuomotor training, ideomotor training, introspective rehearsal, implicit practice, sofa training. Assuming mental training did work—which was the first thing Straub needed to establish—what aspects of the training made a difference? Which programs did a better job? How comparable were the techniques to physical practice?
Straub, who was teaching a course in kinesiology and biomechanics at the time, decided to find out. He had ample laboratory space, enthusiastic students, and three commercial mental practice programs to test. In choosing a sport, Straub considered several criteria. It should be easy to learn, simple to score, and permit individuals to improve over time. So he settled on darts.
Straub recruited seventy-five undergraduates, male and female, for an eight-week experiment. On day one they assembled in a large, well-lit room with a regulation dart board and spent ten minutes warming up. Then they made fifty dart throws each to establish their baseline scores.
A dart board is divided into numbered sections that score from one to twenty points. Circular wires divide each pielike section into areas that earn single, double, or triple points. The red bull’s-eye scores fifty points. After throwing fifty darts, a player can score between zero and 3,000 (that is, if each dart hits the triple zone of the twenty region, you get 50 times 20 times 3, which equals 3,000).
The students were then assigned to one of five groups. The first, a control group, was instructed never to play darts; they only needed to return after eight weeks to throw another fifty shots. The second group threw fifty darts for thirty minutes a day, five days a week, for two months, and kept track of their scores. The remaining three groups were assigned one of the three mental training programs. They alternated between mental training and physical practice. They would spend one day throwing the fifty darts for half an hour, and the next day they would wear headsets, relax, and listen to training tapes for thirty minutes.
Each training program emphasized body awareness, imagery, and relaxation. In one of them, students were told to visualize themselves sitting in a big easy chair facing a large viewing screen. They should see themselves positioned at the throw line and then feel the dart in their fingers, feel it release, see and hear the dart enter the bull’s-eyes, and experience the pride and satisfaction that comes with performing well.
After eight weeks, seventy students (five had to drop out due to scheduling problems) took a post-test of fifty dart throws, and their scores were tallied. As expected, the control group showed no improvement. The group that threw darts daily improved, on average, by 67 points. The three groups that practiced along with mental training improved, on average, by 111, 141, and 165 points.
Even today, Straub says these results surprise him. He never expected to find that mental practice could play such a powerful role in skill acquisition. His study, which is widely cited in sports psychology journals, was one of the first to show that the effect was real. The next task was to tease it apart and figure out the relative contribution of each exercise to overall performance.
Practice Makes Perfect
Alvaro Pascual-Leone is a professor of neurology at Harvard Medical School and director of the Center for Noninvasive Brain Stimulation at Beth Israel Deaconess Medical Center in Boston. Born in Valencia, Spain, he trained in his native country, Germany, and the United States before joining the Harvard faculty in 1997 with the goal of exploring the brain using powerful electromagnets.
The technique he uses is called transcranial magnetic stimulation, or TMS. The doctor wields a heavy wand with a figure-eight-shaped coil on the end. When he holds the wand over a volunteer’s scalp, the magnet discharges, which induces a weak electrical current an inch or so below, down in the cortex itself. It’s like a magic electrode that can probe and zap the brain remotely. Wilder Penfield would have been green with envy.
What do you think happens when a TMS magnet is used to stimulate, say, the ankle region of a volunteer’s primary motor map? At high power it induces a twitch in the ankle, just as Penfield described in his patients. At low power you may not see a twitch, but it still has an effect. The homunculus is still sending a signal down to the ankle muscles each time the TMS coil goes “pop,” but the signal doesn’t quite reach the threshold required to trigger a full-blown twitch. Still, the muscles respond by tensing ever so slightly, and this tension can be measured by electrodes taped to the skin. By probing around people’s primary motor maps in this way, Pascual-Leone can map out the location and size of their homuncular ankle region, elbow region, neck region, you name it.
Among other things, Pascual-Leone is interested in using TMS to see how the primary motor map changes when the brain learns a new skill. “The brain changes with anything you do, including any thought you might have,” he says. Any time you learn something new, any time your brain deems an experience worthy of remembering over the long term, new connections sprout between cells and previously existing connections are strengthened. The process is called plasticity.
As a self-described “fanatical” soccer player and “avid” tennis player, Pascual-Leone decided to investigate how the brain changes with physical practice. Specifically, what happens to your motor maps as you improve your skills at a sport or an instrument?
In 1994 he ran an experiment to find out. He started screening volunteers and accepted only right-handed people who neither played a musical instrument nor had ever learned to touch-type. The subjects came to the motor control laboratory at the National Institutes of Health, where Pascual-Leone was working, on five consecutive days. They were taught to perform a five-finger exercise on a piano keyboard connected to a computer. It went like this: thumb, index finger, middle finger, ring finger, little finger, ring finger, middle finger, index finger, thumb, index finger…repeat. They were instructed to perform these finger movements fluently, without pauses, without skipping any keys, and while paying special attention to the steady interval and duration of each key press. They had to perform at a fairly fast pace marked by a metronome.
Before training began, Pascual-Leone used TMS to measure the size of each subject’s finger maps in his or her left cerebral hemisphere (which controls the right hand). Every day after that, they practiced for two hours and then were tested to see if they could do twenty repetitions of the five-finger exercise without errors. Everyone got better as the week progressed.
Their cortical finger maps were remeasured each day. Lo and behold, by the end of the week, the maps for each set of muscles for each finger had increased significantly in size. Physical practice literally increased the size of the brain map involved in acquiring a new skill, piano playing. Plastic remappings like this occur when you learn or improve at any physical skill, be it guitar playing, golf, tennis, baseball, or dancing.
That was phase one of the experiment. The following week, the subjects were divided into two groups. One continued daily practice for another four weeks. The second group stopped practicing. In the non-practicing group, the finger maps returned to pre-practice size after one week. In the group that kept practicing, the enlarged finger maps also got smaller, even as their performance continued to improve. That may strike you as a very odd and inconclusive result: The map shrinks with no practice, and the map shrinks with practice. What to make of that?
Pascual-Leone says the motor maps involved in any skill—those that send commands to your muscles to perform a task—are reorganized by physical practice. In early practice sessions, while you are still a novice, your finger maps grow in an exuberance of neural rewiring, seeking and strengthening any connection patterns that maximize your performance. If you then stop practicing, your finger maps stop adapting and slump back to their original size. But if you stick with practice over time, you reach a new phase of long-term structural change in your maps. Many of the novel neural connections you made early on aren’t needed anymore. A consolidation occurs: The skill becomes better integrated into your maps’ basic circuitry, and the whole process becomes more efficient and automatic.
There is one more level to all this, and that’s true expertise, or virtuosity. People who practice complex motor skills day in, day out, for years on end, always striving for perfection, show motor maps that are again increased in size. For example, a professional pianist like Gary Graffman unquestionably has enlarged hand and finger maps. His maps are larger than average because they are crammed full of finely honed neural wiring that gives him exquisite (and hard-earned) control of timing, force, and targeting of all ten fingers. A violinist like Itzhak Perlman will also have an enlarged hand map—but only one. The hand map that controls his string-fingering hand, to be exact, is like the pianists’. But his homuncular bow hand is indistinguishable, at least to the naked eye, from any nonmusician’s. His bow hand is deft, yes, but the level of coordination involved is not nearly the same, and the map does not get beefed up beyond normal.
Here is one more interesting fact about expertise: As you gradually master a complex skill, the “motor programs” it requires gradually migrate down from higher to lower areas in the frontal cortex and to subcortical structures. Imagine a guy who signs up for ballroom dance classes. Like all novices, he is terrible at first. During his first several lessons, he is processing his dance-related movement combinations up in his higher motor regions, such as the supplementary motor area. This area is important for engaging in any complex and unfamiliar motor task. The dance moves are at first very complex for him. He needs to pay attention to them constantly, and even so he often loses track.
He sticks with it, though, and after a couple of months he is getting a lot smoother. He is using his supplementary motor area much less for his dancing these days. Many of the motor command sequences he is using now have been transferred downward in the cortical hierarchy, to reside mainly in his premotor cortex. He’s become a competent dancer. He’s not Fred Astaire, but he needs to pay less attention to the basics now. He makes far fewer mistakes. He can improvise longer and longer sequences.
Finally, if he practices often for many months stretching into years, eventually his premotor cortex delegates a lot of its dance-related sequences to the primary motor cortex. Now he can truly be called a great dancer. Dance has mingled intimately with the motor primitives in his fundamental motor map. The dance has truly become part of his being.
Imagining Versus Doing
As a weekend athlete, Pascual-Leone says he was curious about mental practice and sports. “Anybody who likes watching sports can see that certain athletes appear to mentally rehearse what they are about to do,” he says. “You can see it when they’re preparing for a free throw or getting ready to bomb down a slope in a ski slalom race. Before they get going, they prime themselves.”
Many famous musicians do the same thing. Vladimir Horowitz practiced mentally before concerts to avoid disturbing his motor skills; feedback from pianos other than his own Steinway was upsetting. Arthur Rubinstein, eager to enjoy life and practice as little as possible, used mental rehearsal to minimize time spent sitting at the piano. A violinist who spent seven years in prison and practiced playing in his mind every day gave a flawless performance the night he got out of jail. Injured ballerinas have been known to lie on the floor running through dance steps with their fingers to retain their skills.
So Pascual-Leone repeated his five-finger exercise with one specific form of mental practice: internally generated motor imagery.
Imagery takes different forms that are important to distinguish. You know what it is like to imagine an object. Close your eyes and picture a hippopotamus. Now imagine a belly dancer. This is visual imagery. You are the spectator. Visual imagery engages parts of your brain involved in visual perception and conjures up pictorial memories of what you have seen with your eyes.
Motor or kinesthetic imagery is the process of imagining a movement. Imagine yourself erasing a blackboard, signing your name, or washing a dish. You are the actor. You perform the movement, virtually, in your mind. You aren’t using your mind’s eye so much as your mind’s body. Motor imagery engages a subset of your body mandala, including maps involved in motor planning and proprioception. It simulates the inner feeling of an action.
Using the same setup as before, Pascual-Leone’s new subjects spent two hours a day five days a week imagining the five-finger piano key strokes. They were told to repeat each finger movement mentally, as if they were playing. They could rest their fingers on the keyboard but were not allowed to move them in any way.
The results were astonishing. After one week, motor imagery practice led to nearly the same level of body map reorganization as physical practice. As far as your motor cortex is concerned, executed and imagined movements are almost identical.
The “almost” is fascinating. When you mentally rehearse a movement, all but one of the brain regions that control your movements become active in the absence of movement. You imagine throwing the dart but your body is immobile. You imagine pressing the piano key but your muscles are still. So motor imagery is the off-line operation of your brain’s motor machinery unfolding as if it were happening in real time. It takes you about as long to imagine walking across your bedroom as it would if you actually did the walk. Such a walk takes longer if you imagine yourself carrying a heavy box. If you imagine yourself running, your breathing speeds up and your heart rate increases. If you imagine moving your little finger for ten minutes a day, after four weeks it will be up to one-fifth stronger.
Coaches and athletes of every skill level mustn’t ignore this. While many types of mental practice are undoubtedly helpful, motor imagery is the only technique that alters your body maps in the same way physical practice does. Visual imagery (as from a spectator’s point of view), relaxation, hypnosis, affirmation, prayer, and other techniques may help you in one way or another, but will not alter your motor maps. Remember, the students in Straub’s dart experiment who improved the most were those who carried out motor imagery.
The Emulator Within
Your motor system has many more components than the primary motor homunculus. The primary motor cortex contains your body’s “motor primitives”—the most basic building blocks of intentional action. It is up to a gaggle of higher-order body maps to come up with useful and appropriate combinations of those primitives. These maps are also involved in planning and transforming goals into action. And importantly, they let you engage in motor imagery. When you imagine a movement, your primary motor cortex is inhibited. You do not move a muscle. Yet your higher motor regions are screaming along at full speed, carrying out familiar motions.
Another interesting thing about these higher-order maps is that they represent all your movements before you carry them out. Your actions, and your ability to imagine them, are driven by internal models in the mid-and high-level echelons of your body mandala, rather than directly by what is happening in the world outside your body. These models are locked and loaded and ready to deploy by the time you become consciously aware that they are, in fact, what you intend. This has profound implications for people who are paralyzed by a stroke, lose a limb, or sever their spinal cords. Some people also see it as a threat to traditional ideas about free will.
Rick Grush, a neuroscientist at the University of California at San Diego, calls this phenomenon faux proprioception. When you move your limbs for real, signals are sent to your muscles, your muscles move, and your brain receives feedback from your touch receptors and proprioceptors. Your body mandala integrates this to give you a felt body sense of the motion.
But during motor imagery, no signals are sent to your muscles. Instead, they pass through what Grush calls an emulator—a brain circuit that mimics the motor action. When you engage this circuit, your brain experiences a faithful copy of the movement, or faux proprioception.
Why have an emulator? One reason is that you would be a hopeless klutz without it. The environment changes rapidly. You need to predict what is happening in the world to cope with its complexity. For example, let’s say you’re playing with a fast, wriggly puppy and it starts to run away from you. You want to catch it, and as fast as you can, you formulate a motor plan to make it happen: Reach out, grab collar, pull. But it takes a tenth of a second for that motor command, carried as electrical impulses, to travel down your spine and out to your hands. By the time you reach out to grab the puppy, your hand is guided by information that is already at least a tenth of a second old. If the puppy is a spry one, you just claw the empty air.
But your brain has a clever solution. It overshoots its reach. Like a quarterback throwing the ball ahead of a running receiver, your visual-motor maps make up for the delay by acting on a prediction instead of what you can immediately see. Perception and action are inherently predictive. Your brain creates mental models of your body and the world, and is constantly updating those models with newly arrived information from the senses and constantly extrapolating predictions from them.
Sometimes your brain adds more lead time, beyond what it needs to send a command down your spinal cord. If you tap along with a rhythmic noise or flash of light, you will initiate the tap a split second ahead of the actual rhythm. Your brain uses this extra anticipation as a way of coping with an erratic, changing environment—as on the playing field of almost any sport.
For example, if you were going by immediate sensation alone, a tennis serve would be too fast for you to react to. But the reason you can return at least some of the serves dished out against you is you read the body movements of your opponent. You start moving in the correct direction before her racket touches the ball.
The world-famous Brazilian soccer player Pele developed a trick that reliably won penalty shots. As Pele approached the ball, the goalie would read his body language and begin hurling himself to the left or right to make the interception. But Pele made a small stop, called a paradinha, a fraction of a second before he kicked the ball. It was enough time for him to see which way the goalie was moving and to kick in a different direction.
Golf and the Brain
A few years ago, when he worked at the Cleveland Clinic Foundation, Dr. Jeffrey Ross, a neuroradiologist now at the Barrow Neurological Institute in Phoenix, Arizona, wondered what would happen if he put golfers of various skill levels into a brain scanning device and asked them to imagine their golf swing. In such scanners, called functional magnetic resonance imaging machines, or fMRI, brain regions that consume the most energy “light up” the brightest, in what is thought to be a surrogate for effort.
THE BRAIN-MACHINE INTERFACE
A paralyzed man sits in a wheelchair and controls a computer cursor with his thoughts. He can answer e-mail, turn on his television, and move objects with a robotic arm—simply by thinking of those actions.
A physically active fourteen-year-old boy, who is being evaluated for epilepsy surgery, plays “Space Invaders” without using a joystick or lifting a finger. He merely thinks of blasting aliens off the computer screen, and zap, they’re toast.
You may have read accounts of these seemingly amazing feats and wondered, How in the world do they do that?
Easy. It’s simply a matter of knowing how to read signals from your body maps and convert them into a language that a computer or a robot can comprehend.
Recall that your movements are computed at multiple levels of your motor cortex—before you take any action. The direction and path that your arm will follow in reaching out to pick up that book lying on the table is calculated in advance of the movement.
The basic setup for a brain-machine interface to control a robotic arm. Microelectrodes implanted in the brain radio their readings of neural activity to a computer, which remaps the neural data into a digital control signal that drives the prosthesis. Visual feedback from the eyes and eventually tactile feedback from the arm, which will be piped directly into the brain’s primary touch map through another set of implanted electrodes, will create a closed-loop system—in other words, complete integration of the robotic arm into the patient’s body schema.
Other regions of your brain (prefrontal and parietal) deal in even greater abstractions. They transform vision—I see the book in front of me—into planning how to reach for and grasp the book. Basically, they figure out your intentions and goals and pass commands down to your motor areas to do the desired deed.
It is possible to insert electrodes into these brain regions and record the firing patterns of neurons at work. Some patterns reflect the activity of cells involved in limb movement. Other patterns reflect intended actions. In either case, the information is mathematically translated into computer code that can operate a cursor or robot arm.
Most such experiments have been carried out in rats and monkeys. For example, healthy monkeys have learned how to bring food to their mouths via a robot arm that is operated by their thoughts. Once the monkeys realize how easy it is, they let their healthy arms go limp. It is as if the robot arm has been completely absorbed into their body schemas.
In developing effective brain machine interfaces for people, researchers face huge hurdles. They do not yet know how many neurons—tens, hundreds, thousands?—they need to record from to get the best results. Implanting electrodes directly into the brain is invasive and inherently dangerous. Electrodes are not compatible with human tissue. The body coats them in scar tissue and they fail. Infection is a constant threat.
It is safer to read electrical signals from the scalp, but these systems tend to be slow and somewhat clumsy in terms of how users adapt to them. Such electrodes listen to signals from millions of neurons all over the brain, resulting in less precise information.
The greatest success thus far has come from implanted electrodes. Matt Nagle was paralyzed below his shoulders after being stabbed in the neck during a mêlée at a beach in July 2001. In 2004, when he was twenty-five years old, he had an array of ninety-six electrodes pasted directly onto his motor cortex. Researchers asked him to follow a moving cursor with his eyes while imagining that his hand was moving it. The electrodes picked up patterns involved in his imagined movements and sent them to a computer. At first, Nagle had trouble moving the cursor to a target. But with practice he gained enough control to flip switches, retrieve e-mail, and send simple commands to a robot arm.
After nine months, the device came out. Nagle says that he is happy to have volunteered.
Another temporary user of implanted electrodes is an unnamed fourteen-year-old boy from the Midwest who was being evaluated for epilepsy surgery. To prepare for surgery, physicians implanted an array of electrodes and waited for a seizure to occur. That way they could map the exact location of the abnormal tissue involved.
While waiting, researchers asked the boy to move his limbs, talk, and then imagine moving his limbs. They matched brain signals to each act. Then they asked him to play a video game, “Space Invaders,” by imagining his movements.
The boy learned to play the game instantly by moving the cursor with his thoughts. He mastered two levels of the game without breaking a sweat. Later, the electrodes came out and he got on with his life.
In the future, researchers say they want to add feedback—artificial senses of touch and movement—from robot arms or artificial limbs directly into the user’s brain. Ultimately, they might be able to bypass a broken spinal cord and rewire the body to restore natural movement. Or build artificial limbs that act like real arms or legs.
Such therapies could help people with all kinds of problems—spinal cord injury, stroke, Lou Gehrig’s disease, muscular dystrophy.
Or, brain-machine interfaces, assuming they are safe, could be hooked up to your normal brain. Just think, you’d be able to make a robot do your bidding. Any ideas of what you would do?
Five men, aged twenty-four to fifty, were scanned as they used motor imagery to imagine themselves on a practice tee taking golf swings one after another for several seconds. The players held different handicaps between zero and 13 (the lower the handicap, the better the golfer).
Ross confirmed what neuroscientists had been saying: Imagining a skilled movement activates exactly the same brain regions that become active during real play—namely, action planning areas—minus the primary motor cortex. He also found that the brains of the better golfers used less energy than those of the duffers. The better you get at golf, the more efficient your brain is while playing it.
To understand why, think how complex systems in the natural world are built from simple parts. Language is composed of sentences, which are built out of words, which are built up from consonants and vowels. Likewise, your movements are built out of motor primitives that are combined into simple actions that are combined into goal-directed action sequences, and so on. If you really excel at a sport or an instrument, you almost certainly began playing it before you entered puberty. The complex motor skills required for mastery became deeply ingrained in your body maps as a child. If you kicked a soccer ball around the streets of São Paulo from the age of three, you have better eye-foot coordination than a kid from Kansas who developed superb hand-eye coordination from throwing baseballs in Little League.
Basic movements in any sport can be described and taught. In tennis, your bones and muscles have many degrees of freedom for playing the game. A teacher breaks it down: You throw the ball, move your pelvis forward, bend your knees and elbow. Transitional states are explained: Rotate your upper body, accelerate your racket, stretch your whole body, hit the ball, flap your wrist, bend your body forward, let the racket flow through with the motion. As you learn a tennis serve, each component is stored, mapped, and activated when you attempt the movements.
Among novices, the shape or configuration of each piece of the action is clunky and poorly coordinated. You throw the ball too high, your pelvis tilts back, your wrist does not bend with sufficient force. You’re struggling to put all the parts together, verbalizing each step in your mind.
Coaches say that people should not try motor imagery at this juncture because they don’t have the basic motor maps required for the movements being learned. You cannot mentally practice a skill until it is actually related to your muscles. You can only imagine movements you have done previously and have a minimum level of competency with. For example, you can play at imagining you are able to bang out an intense piano concerto, but unless you can actually play the piano to begin with, you’re not going to get a rehearsal benefit.
It is when movements are fluid, automatic, synchronized, and tuned that imagery becomes a useful tool. Indeed, there’s a saying among golf coaches: If you want to make a good golfer into a bad golfer, ask him whether he breathes in or out before hitting the ball. The fact is it doesn’t matter; but it can be something that simple that ruins a player’s game. Golf is played at the limits of the nervous system’s ability to consistently reproduce precise movements. A critical component of golf mastery—and more than a few other sports, for that matter—is the ability to perform without thinking. You need attention at the beginning of training, when the movements are being orchestrated by your supplementary motor cortex; but as the skill migrates down to your lower-level motor maps, attention tends to just get in the way and muck things up. It is like a tech-illiterate CEO who decides to head down and start micromanaging things in the IT department. Assuming you aren’t a novice, your body schema just doesn’t need your conscious thoughts or second guesses trying to interfere with your well-practiced motor programs. You don’t need to pay attention to your breathing, limb position, or other postural minutiae. An expert plays for the goal of the action, not its components.
Mama’s Loving Touch
Many athletic prodigies have naturally high sensorimotor integration between and within their frontal and parietal lobes. These are the graceful and sure-footed folks, the ones who own the basketball court when they’re on it, or could find their way around the machine shop with their eyes closed, or have the enviable ability to pick up tricky new dance moves after seeing them done just once. On the flip side are the klutzes, those who seem to keep only a very sketchy, anemic map of the space behind them when their back is turned, whose proprioception is conspicuously poor, who kick their own heels as they walk and backhand glasses of water off dining tables.
Little is known about the organic differences between naturally high body awareness types and the congenitally clumsy, but neuroscientists are certainly keen to get a handle on this question. One thing that’s safe to say is that, as with just about every other complex human trait, it’s not a question of nature versus nurture, but rather how nature and nurture get woven together.
On the nature side, there is clearly genetic variation between different people’s brain wiring. The same area of cortex can vary twofold in size among normal people. So how much does size matter? Scientists recently discovered genes that lay down the primary motor and touch maps before birth. By manipulating these genes in the lab, the scientists produced mice with miniaturized or supersized body maps and noted that both the under-and overendowed animals were klutzy. The key turned out to be not absolute size but relative size compared with other brain areas they were connected to. Such results are a good though modest first step toward decoding the underlying differences between the Mozarts and the Salieris of many arts and disciplines.
Biology is part of destiny, but not all of it. Early experience and rearing clearly play their part. To be truly world class you need a double hit of luck: You need the biological endowment of high-quality circuits for sensorimotor integration in your body mandala, and you need the opportunity to get lots and lots of practice starting when you are young.
Seth Pollak, a psychologist at the University of Wisconsin and an expert on child development, shows just how important movements are to normal brain development. But he begins with an unusual video clip—the one that inspired him to study children raised in Eastern European orphanages and who were later adopted by American families.
The film depicts mothers and babies in Mali. People in Mali have a strong cultural belief that babies with crooked legs are unattractive, Pollak explains. But of course, all newborns have scrunched-up legs from being in the womb. So what do Malian mothers do? When they bathe their infants, they stretch out their legs with a firm stroking motion. In the video, a mother yanks at her baby’s feet as if she were pulling taffy. Then she grabs his ankles and hangs him upside down.
“Look at that,” Pollak marvels. “It’s amazing.” A mother is swinging her tiny infant by the feet, upside down.
“They do this for months, and do you know what happens?” Pollak asks. He fast-forwards the video. “Look at that!” The camera pans around a group of mothers and children where the youngest, who are merely six-and seven-month-old babies, are walking. They toddle along as if they were twice their age.
Babies in Mali walk at younger ages than babies anywhere else in the world, Pollak says, because the part of their brain that controls movement gets hyperstimulated. Their motor and touch maps reach early maturity, thanks to all the help they get from their attentive parents—who naturally want attractive, straight-legged children. (It’s definitely not a good idea to try this at home unless you get expert instructions from Malian parents!)
Pollak says the babies in Mali got him to thinking about an opposite problem. Babies born into Romanian and Russian orphanages after the Soviet empire imploded were often kept two or three to a crib. With not enough caretakers to go around, they received very little personal attention—no gentle touches, no soft kisses, no snuggly hugs. They were not allowed to crawl. Most remained in their cribs, looking out at the world but unable to freely explore or interact with it. If they did become mobile, many were tied to cribs or chairs. This was not done to abuse the children, Pollak says, but to keep them from harming themselves. Adult attention was in short supply.
Fast-forward several years, after hundreds of these children were adopted by middle-class American families, many of them settling in Wisconsin. Most had lived the first twelve to twenty-four months of their lives in such orphanages.
Pollak wondered about the consequences of not being allowed to crawl. “We used to think the motor system is hardwired, that people are destined to move in certain ways,” he says, “but that’s not so.” You need to interact with the physical world to build normal body maps, and you need to do it during a sensitive developmental window in infancy.
To see the effects of early deprivation on body maps, Pollak ran a pilot study. Twenty-two of the Romanian and Russian orphans aged three to four came to his lab to undergo standardized tests. Their language and general IQ were fine, he says. But in eight domains of motor development, they were two to three standard deviations below the norm.
“That is a whopping statistic,” he says. “These kids are not just a little delayed. In comparison, only one percent of the children in the world should score that badly. And all twenty-two of these kids scored that low.”
The children were asked to put one hand on their shoulder and one at their waist, then change sides: Right hand at waist goes to right shoulder while left hand at left shoulder goes to waist. They could not do it, Pollak says. They had to bring one hand completely down before they could raise the other. The children were asked to stand on one foot, like a flamingo. They all toppled over when they tried.
But perhaps the adopted kids had not been in the United States long enough, with good public schools and homes with jungle gyms. So Pollak and his colleagues recruited eighteen ten-year-old Romanian and Russian orphans who had been adopted eight or more years ago. Surely they would have made up the deficit by now.
Kids everywhere love to walk on railroad ties or curbs. But the orphans, when asked to walk a balance beam placed on the floor, could not take more than one step. They toppled to one side instantly. Asked to swing their left arm and leg back, right arm and leg forward, they could not do it.
These studies, which now include 150 children, show that body maps for balance, body sense, and movement can fail to develop normally when babies are not allowed to move freely. If you were raised in an understaffed Romanian orphanage, your body maps are stunted.
As for the rest of us, odds are that if you have a sport or a similar motor-intensive hobby, you understand you missed the boat to superstardom long ago and just play for fun and health. (You may take some solace from the fact that basketball superstar Michael Jordan could not play baseball very well.) Nevertheless, weekend warriors can exploit knowledge of body maps to improve their game, within some limits. There is such a thing as natural talent. You will never be able to run as fast as athletes from the Kalenjin tribe in Kenya, who possess gene variants that affect the mass and shape of their leg muscles. Their cellular metabolism is more efficient. They need 8 percent less energy to run a kilometer than most of their competitors. Physically, you will never be Tour de France legend Lance Armstrong. He has a higher oxygen-carrying capacity in his blood, less lactic acid, a bigger heart, and better slow twitch muscles (the kind of muscle you need to carry you through long, sustained aerobic workouts) than most human beings. And like all great athletes, he trains harder, longer, and better than most of his competitors. He has a mental toughness that puts him in a class by himself.
Meanwhile, the rest of us mortals can apply lessons from the neuroscience lab. For example, Pascual-Leone found that the level of performance after five days of motor imagery was equivalent to three days of physical practice. But when he added one day of physical practice to five days of motor imagery, his subjects were as good as those who practiced only physically for five full days. This means motor imagery can give you a distinct advantage in your training. You can get better with less rather than more physical practice. And it’s gentler on the knees.