myelination
Moontower Munchies #135
Friends,
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I was doing some zone 2 stationary bike earlier this week, my excuse to binge Rick Beato videos, when YouTube’s auto-play served me gold from a musician named Nathan. The title of the video is:
3 hacks for getting so good at guitar, it feels like cheating (neuroscience based)
I link to it below, but why am I sharing a guitar video?
The guitar is besides the point. This video is one of the best things I’ve ever seen on the general topic of skill development, a topic that your “like” and “sharing” activity indicates a strong interest in.
[The recent post slow is smooth and smooth is fast seemed to have a settling message that resonated. Its thrust is something that grounds me as well, so I’m with you.]
We will get to the skill development material below, but this video got me thinking about skills in general. The word “skill” has a narrow connotation. Remember this guy:
A less pointy idea is simply competence. Great skill is extremely high signal. The job is going to get done. While general competence can be more nebulous or even be faked. I watched the pilot episode of Stick and saw both narrow skill and broader aptitude in Owen Wilson’s protagonist. He’s a world-class (although washed-up) golfer, but in the opening scene, you are introduced to his world-class ability to bullshit when he upsells a set of fancy clubs as a clerk in a sporting goods store.
There are skills vs “attributes to succeed”. Some aptitudes lie on the other side of 10,000 free throws or 10 years of piano scales. Others are more of an, I don’t know, disposition. For example, a great salesperson or broker needs to be excellent at peopling, but perhaps even more so, they need to be relentless. Persistent, even irrational, optimism in the face of constant rejection. I suspect it’s trainable through reinforcement. You can use external incentives to motivate someone until they eventually discover that the fruits of their persistence are intrinsically rewarding. (Parents don’t despair…my eldest is 12 and only now I’m starting to see glimpses of this.)
Self-efficacy and its byproducts, a sense of control and (maybe?) happiness, depend on matching your activities, goals, and career to the intersection of your skills and values. That might sound disheartening to someone who never put in the reps to develop high-signal “skills”. But if you are extreme on a dispositional characteristic such as being naturally upbeat, this can be a highly adaptive stand-in for otherwise legible skills (like nunchucking).
Self-knowledge requires knowing what dispositions you have at a scarce dose (positive or negative) and taking advantage or avoiding paths that have hefty loadings on those qualities.
Anyway, let’s get back to skill development.
The branch of cognitive psychology that focuses on learning is the scientific foundation for skill development. My earliest foray into this topic was reading all of Scott H Young’s blog posts. A more more direct way to ingest it would be to simply read his book (which came out after I read his blog):
Ultralearning: The Essential Guide To Mastering Hard Skills And Future-Proofing Your Career
If you prefer interviews, Dwarkesh had him on his show in its early days back in 2020 while Scott was promoting the book. Scott’s obsession with mastery is intertwined with his insane MIT Challenge.
In his book Range, David Epstein has a chapter devoted to learning science as well. I’m not the only one who noticed. Fellow moontower reader and friend Adam Butler was recently on the Intentional Investor podcast. He told Matt Zeigler that Range had a large influence on how he raised his children, with a special shout-out to the learning section. (My 12-year-old is currently reading an edition of Range targeting middle-schoolers).
More world collision…David recently published this short post with callbacks to key concepts from learning science in the context of recently fashionable concerns (emphasis mine):
How to Use ChatGPT Without Brain-Rot
The authors of the study argue that early, heavy reliance on the AI seemed to have encouraged “shallow encoding”: The work got done, but it didn’t get deeply integrated into memory. They also use the term “cognitive debt”: If you repeatedly lean on ChatGPT upfront, you defer effort now but pay later, with weaker critical thinking, poorer recall, and more superficial engagement with ideas.
In cognitive psychology, there is something known as “desirable difficulties.” These are obstacles that make learning more challenging, slower, and sometimes more frustrating in the short-term, but deeper in the long-term. One example of a desirable difficulty involves what is known as the “generation effect.” Simply: forcing yourself to come up with an answer to something before having one given to you primes your brain for subsequent learning. (Chapter four of Range—”Learning, Fast and Slow”—is all about desirable difficulties.) It would seem that, for these essay-writers, ChatGPT was the precise opposite of a desirable difficulty. It allowed the essay writers to give answers before doing their own thinking. Let’s call it an “undesirable ease.”
I was literally lecturing my kids on the cog sci sweet spot of 85%. I doubt that the actual percentage matters, but the concept is that if someone is consistently scoring 100% it’s too easy. It’s review not learning. If you score too low, it’s disheartening and your foundations aren’t properly backfilled.
A few more insights about learning from Range that I’ve shared before:
Testing: Test people before they have a chance to study. It primes your brain and exploits the “hypercorrection” effect — our tendency to remember the correct answer to a question you were initially wrong about.
Interleaving: Mixing types of problems will extend the time it takes to learn one type, but improves the broader ability to match the approach to the type.
“Difficulty isn’t a sign that you’re not learning but ease is”. Your steepest learning occurs when the task is difficult.
Spacing: To maximize stickiness, you actually want to re-learn something just after you have forgotten it!
We will close with that outstanding guitar video that really could have used any domain to drive home the point, but the specific examples of how he drilled the positioning of his pick when switching strings exemplify the depth that skill development is concerned with. It’s also a humbling reminder of what expertise and high standards require. It did not make me feel good about myself. Just the way I like it.
I distilled these key concepts from the video for you to remember and refer to. They are simple to understand but devilishly easy to forget or shy away from when you practice anything.
Myelin
This is the link between behavior and physical adaptation in your body.
Expertise is built through perfect, focused repetitions that thicken myelin, making neural signals faster, cleaner, and more reliable. Myelin strengthens whatever you repeat—good or bad—so attention to detail matters more than raw hours.
Practice doesn’t make perfect; practice makes permanent.
Quotes of note:
“There are three habits that make you so good at guitar that it feels unfair… almost no one does them.”
“An expert guitarist actually has stronger, faster, and better-myelinated neural pathways than most other guitarists.”
“When those pathways get used a lot, your body starts coating them with myelin — a fatty layer that acts like insulation on a wire. The thicker the myelin, the faster and cleaner the signal travels.”
“A strong myelinated neural pathway is built by performing perfect and focused repetitions over a long period of time.”
Deliberate Practice is Micro-Level Problem Solving
Experts zoom into a single mechanical failure, diagnose the cause, correct the movement, and only then add repetition. They don’t run full passages—they break skills into micro-tasks and solve them one by one.
The protocol:
Chunk the skill → detect the error → correct the error → then add volume.
Quotes of note:
“I zoomed into a very specific mistake… and I realized I needed to tilt my pick so that it escaped away from the string on the way back.”
“You have to be careful not to get sucked into mindless repetition… Your brain turns off and you’re just chronically repeating it. You want to stay very mindful as you’re working on the specific details. Then you can repeat mindlessly once the motions are correct.”
Isolation Reduces Cognitive Load
You can’t improve multiple skills simultaneously. Isolating one technique at a time (alternate picking, legato, hybrid picking) lowers cognitive load and accelerates mastery. Experts master fundamentals separately, then recombine.
Mastery grows from fundamentals upward, never from the full skill downward.
Train at the Edge of Ability
The correct practice speed is just fast enough that form nearly breaks.
Too slow doesn’t build adaptation.
Too fast causes you to myelinate errors.
Optimal learning happens just before things start to break down.
Stay groovy
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Lots of good ideas here that apply across so many areas. Thanks.