" To sum up: it's time to rewrite the maxim that practice makes perfect. The truth is, practice makes myelin, and myelin makes perfect. And myelin operates by a few fundamental principles. The firing of the circuit is paramount. Myelin is not built to respond to fond wishes or vague ideas or information that washes over us like a warm bath. The mechanism is built to respond to actions: the literal electrical impulses traveling down nerve fibers. It responds to urgent repetition. In a few chapters we'll discuss the likely evolutionary reasons, but for now we'll simply note that deep practice is assisted by the attainment of a primal state, one where we are attentive, hungry, and focused, even desperate. Myelin is universal. One size fits all skills. Our myelin doesn't “know” whether it's being used for playing shortstop or playing Schubert: regardless of its use, it grows according to the same rules. Myelin is meritocratic: circuits that fire get insulated. If you moved to China, your myelin would wrap fibers that help you conjugate Mandarin verbs. To put it another way, myelin doesn't care who you are—it cares what you do. Myelin wraps—it doesn't unwrap. Like a highway-paving machine, myelination happens in one direction. Once a skill circuit is insulated, you can't un-insulate it (except through age or disease). That's why habits are hard to break. The only way to change them is to build new habits by repeating new behaviors—by myelinating new circuits. "
― Daniel Coyle , The Talent Code: Unlocking the Secret of Skill in Sports, Art, Music, Math, and Just About Everything Else