IMAGE:  April 2003  GRAPHIC:  University of Chicago Magazine
APRIL 2003
Volume 95, Issue 4
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Unexpected Expertise  
Poetic Justice  
Survival of the Richest
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Clouding the Issues

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From the President  

Unexpected Expertise

Dan Dry


John Milton Poise and Noise

Deep in the Albert Merritt Billings building associate professor of neurology John Milton steps side to side as he balances a wooden dowel upright on his fingertip. “I’m getting pretty good at this,” he exclaims.

Milton isn’t clowning around during a break from directing the Hospitals’ Epilepsy Center, where he performs implants of vagal nerve stimulators in severely affected patients. He’s demonstrating his unexpected discovery about the body’s nervous system: it generates random “noise” to handle tasks—like balancing a dowel or standing still without falling—that require response in less time than it takes for a signal to travel to the brain and back (100–200 milliseconds for the stick, 250–500 milliseconds for standing). “If the nervous system can only make a correction every 200 milliseconds,” he asks, “what’s it doing the other 199?”

“Flipping coins.”

In a 2002 Physical Review Letters study, Milton and Juan Cabrera, a physicist in Venezuela, filmed a dozen people balancing the two-and-a-half-foot-long dowel, measured the size of its wobbles, and then correlated them with subjects’ hand movements to keep it upright. About 98 percent of the movements occurred in less than 100 milliseconds. “That tells us something uncontrolled by the nervous system is at work,” says Milton. He calls that something “noise.” “The hand makes little errors in its position. It should move a certain time in a certain direction, but it doesn’t get it exactly right.” The difference between where the fingertip should move and where it goes is measured as noise. And the errors, he notes, actually seem to help: the stick stays balanced only if it is on the verge of toppling over.

Milton isn’t sure why the errors help or how noise works—at this point, his observations exist only as a mathematical formula. But his finding is making neuroscientists rethink their ideas about motor control. Next he’ll research “how you get better” at tasks that require quick but precise reflexes. His focus will be the golf swing—something Milton, with a handicap of 6, is already pretty good at.


Select an expert:

Riccardo Levi-Setti - Trilobites

Richard Epstein - Parking and Property

Mary Anne Case - Toilet Inequities

Roman Weil - Vintage Wine

Robert Grant - Sunken Submarines

David Galenson - Poetic Values

John Milton - Poise and Noise



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