When I started working on this project, I came across an electron microscope photo of myelin. It's not a great image in the usual sense of the word: it's grainy and blurred. But I like looking at it, because you can see each individual wrap, like the layers in a cliff face or the growth rings of a tree. Each wrap of myelin is a unique tracing of

Carol Dweck, the psychologist who studies motivation, likes to say that all the world's parenting advice can be distilled to two simple rules: pay attention to what your children are fascinated by, and praise them for their effort. To which I would add, tell them how the myelin mechanism works, as Dweck herself did in a study that revealed the

Mostly, though, I feel it in a changed attitude toward failure, which doesn't feel like a setback or the writing on the wall anymore, but like a path forward.

As one neurologist pointed out, the mantra “Use it or lose it” needs an update. It should be “Use it and get more of it.”

“The myelin literally starts to split apart with age,” Bartzokis said. “This is why every old person you've ever met in your life moves more slowly than they did when they were younger. Their muscles haven't changed, but the speed of the impulses they can send to them has changed, because the myelin gets old.” The good news is that while natural

If you practice, you can get to the level you want.”

The key is that people have to linger in that uncomfortable area, learn to tolerate the anxiety.

to get inside the deep-practice zone, to maximize the firings that grow the right myelin for the task, and ultimately to move closer toward the day that every coach desires, when the students become their own teachers. “If it's a choice between me telling them to do it, or them figuring it out, I'll take the second option every time,” Lansdorp

“You gotta give them a lot of information,” said Robert Lansdorp, the tennis coach. “You gotta shock 'em, then shock 'em some more.” Shock is an appropriate word. Most master coaches delivered their information to their students in a series of short, vivid, high-definition bursts. They never began sentences with “Please, would you” or “Do you