Inside your brain, there’s a construction crew that never sleeps.
Every time you repeat an action — a card technique, a coin manipulation, even the way you shuffle a deck — your brain wraps the associated nerve fibers in a substance called myelin. Each layer of myelin makes the signal travel faster and more efficiently along that specific pathway. The result is that repeated actions become smoother, faster, and more automatic over time.
This is myelination. And it’s both the best and worst thing that can happen to your practice.
The Highway Metaphor
“Art of Practice” described myelination using a metaphor that made the concept immediately vivid: “Myelination is a process where paths are paved inside our mind. Similarly, like a highway is paved. The very first time you choose and make a decision, the road has been chosen, but as we continue to take the same pathways, it becomes easier each time to go on the same road the next time, and we keep paving over it once we start using them.”
Think of your brain as a landscape. The first time you attempt a new technique, you’re walking through an open field. No path exists. Each step requires conscious effort, deliberate attention, careful navigation.
The second time, there’s a faint trail. The third time, the trail is slightly more defined. By the twentieth time, it’s a dirt path. By the hundredth time, it’s a paved road. By the thousandth, it’s a multilane highway.
The highway is fast, smooth, and efficient. You can travel it without thinking. And that’s the point — myelination is your brain’s way of converting conscious, effortful actions into unconscious, automatic ones. It’s the neurological basis of muscle memory.
The Problem with Automatic Highways
Here’s what the construction crew doesn’t tell you: it doesn’t care where the highway goes.
Myelination doesn’t distinguish between good technique and bad technique. It doesn’t evaluate whether the action you’re repeating is optimal or suboptimal. It simply paves whatever road you use most frequently.
If you spend hundreds of repetitions doing a technique with a slightly incorrect finger position, myelination paves a highway to that incorrect position. The technique becomes automatic — automatically wrong. And the more automatic it becomes, the harder it is to change, because changing it means abandoning a multilane highway in favor of a new dirt trail.
This is why bad habits in practice are so pernicious. They’re not just behavioral patterns you can choose to stop. They’re neurological infrastructure. Physically real pathways in your brain, reinforced by thousands of repetitions, optimized for efficiency. Fighting a bad habit means fighting your own brain’s highway system.
The 99% Connection
Myelination is the mechanism behind the 99% theory. When behavioral scientists say that ninety-nine percent of what you do today is the same as yesterday, they’re describing the behavioral output of a myelinated brain.
Your brain has built highways for your daily routines. Getting up, eating, working, practicing — all following well-paved paths that require minimal conscious navigation. These highways are why routines feel comfortable and changes feel difficult. The comfort isn’t psychological — it’s neurological. You’re traveling on smooth pavement instead of breaking trail through an open field.
In practice, this means that every session spent on routine material further strengthens the highways to your current skill level. The routine becomes faster, smoother, more automatic. And simultaneously, the unpaved roads to new skills become relatively harder to travel, because the contrast between the smooth highway and the rough field grows with every repetition.
This is why the routine expands and the new material shrinks. Your brain is making it neurologically easier to do what you’ve done before and neurologically harder to do what you haven’t. The path of least resistance is always the highway.
Paving Roads to Nowhere
The most dangerous application of myelination in practice isn’t bad technique — it’s stagnant technique.
When you practice a technique that’s at ninety percent proficiency, each repetition adds another layer of myelin to the “ninety percent” highway. The technique becomes more efficiently ninety percent. The neural pathway optimizes for the current level, not for improvement.
This is why grinding the same technique for weeks without progress isn’t just unproductive — it’s counterproductive. You’re building infrastructure that locks in the current level. The highway to “ninety percent of this technique” becomes so well-paved that the detour to “ninety-five percent of this technique” becomes increasingly unappealing to your brain.
Your brain, optimizing for efficiency, says: “The highway is right here. It’s smooth, it’s fast, it goes exactly where we’ve been going. Why would we take that dirt road?”
The answer — “because the dirt road leads to somewhere better” — doesn’t register neurologically. Your brain’s construction crew doesn’t evaluate destinations. It just paves the roads with the most traffic.
Deliberate Unpaving
Once I understood myelination, I realized that effective practice requires two simultaneous activities: paving new roads and deliberately avoiding over-paving old ones.
Paving new roads means spending practice time on challenging, unfamiliar material. Material that forces your brain to create new pathways rather than reinforcing existing ones. This is the deep end practice I’ve written about.
Avoiding over-paving means limiting the time spent on routine material. Not eliminating it — routine maintenance has its place. But limiting it, so that the highways to your current level don’t become so dominant that the detours to your next level become impossible.
The balance is delicate. Too much new material and the old techniques deteriorate because their highways don’t get enough traffic to maintain them. Too much routine material and the old techniques calcify at their current level because no new highways are being built.
The solution was elegant: naturals practice their hardest material first, when energy and focus are highest, and then drop down to routine material to maintain it during the low-energy tail of the session. The new highways get the premium construction resources. The old highways get basic maintenance. The overall network expands rather than just reinforcing the same routes.
The Implication for Mistakes
Myelination also explains why mistakes during practice are more serious than they seem.
Every repetition of an incorrect technique adds a layer of myelin to the incorrect pathway. The mistake isn’t just a momentary error — it’s a construction event. Each wrong repetition builds a tiny bit more highway in the wrong direction.
This is why practicing while fatigued is risky. When focus is depleted and concentration is low, the likelihood of imprecise repetitions increases. Each imprecise repetition adds myelin to the imprecise pathway. Over time, the imprecise version of the technique becomes the automatic one, because it has more highway infrastructure than the precise version.
This is another argument for stopping when focus fades. Not just because low-value energy is unproductive, but because low-value energy produces imprecise repetitions that build highways to the wrong destination.
Choosing Your Roads
The actionable insight from myelination is this: you are always building highways. Every practice session, every repetition, every moment of engaged practice is a construction event. The question is whether you’re building roads that lead to improvement or roads that lead to stagnation.
Building roads to improvement means spending the majority of your construction resources — your high-value energy and focused attention — on new, challenging material. These are the dirt trails that need to become highways. These are the destinations you haven’t reached yet.
Building roads to stagnation means spending those same resources on material you’ve already mastered. These highways are already built. Adding more pavement to them doesn’t take you anywhere new.
The metaphor isn’t perfect — in reality, existing highways do need some maintenance, and completely neglecting them will cause deterioration. But the balance should heavily favor new construction over maintenance. The ratio I’ve found effective is roughly seventy percent new road construction and thirty percent highway maintenance within each session.
The Uncomfortable Truth
Myelination reveals an uncomfortable truth about practice: you cannot be neutral. You are always either building toward improvement or building toward stagnation. There is no static state.
Every repetition either paves a road forward or further entrenches the roads you’ve already traveled. The brain’s construction crew is always working. The only question is what they’re building.
This means that every minute of every practice session carries weight. The warm-up minutes aren’t free. The routine minutes aren’t neutral. The fatigued minutes at the end of a long session aren’t harmless. Every minute is a construction event, and every construction event either expands your highway network or reinforces the existing one.
Once you understand this, the case for strategic, intentional, energy-aware practice becomes not just logical but neurologically necessary. You’re not just optimizing your time. You’re directing the construction of your own brain’s infrastructure.
Choose your roads carefully. Your brain will build whatever you tell it to.