Don't Offload the One Thing That's Ours: Notes from John Medina's Brain Rules

Twelve principles. One page. That's all Brain Rules is.

I keep coming back to that one page. John Medina is a professor of bioengineering — not a self-help guy, not a productivity influencer. A scientist. And he distilled what we actually know about how the brain learns into twelve rules you can read in five minutes.

Two have already changed my week.

Repeat to remember. Remember to repeat.

It's a mnemonic about a mnemonic. The first half tells me what to do when I want to learn something. The second half reminds me to actually do the first half. It is so well-built it folds in on itself.

Exercise boosts brainpower.

I used to treat this as a trade-off. Body or brain. Pick one. I almost always picked the brain — read instead of run, code instead of walk. Brain Rules says no. There is no trade-off. The brain runs better when the body moves. So now when the choice comes — and it comes most days — I go for the run.

There are more.

• Sleep is when the brain literally cleans itself. The glymphatic system flushes out beta-amyloid — the same protein implicated in Alzheimer's. Skipping sleep is not toughness. It is letting the trash pile up.

• Stress kills learning. A stressed brain doesn't encode well. So if you want to learn, you have to destress. I cannot make music. I love listening to it. Brain Rules gave me the excuse — music is good for the brain, especially for attention. Now when I notice the stress, I notice the playlist.

• Attention. In an age of distraction, Medina's plea is simple: pay attention to what matters. My version: scan for anomaly. The new word. The unfamiliar concept. The image that doesn't fit. If I don't understand it, I lean in. If I do understand it, I repeat it so it sticks.

Here is why all of this matters more now than it did five years ago.

We are in the age of AI. Every search bar, every chat window, every model is offering to remember for us, think for us, summarize for us. The phrase researchers use is cognitive offloading. The early evidence is not great. The more we offload, the less we keep. Use it or lose it is not a slogan. It is neuroscience.

Medina's antidote is older than any of this. We are explorers by nature. Babies prove it. We were born curious — born to wonder, to test, to be wrong, to ask again. AI is not the threat. The threat is letting our explorer brains atrophy because we stopped using them.

I have one reservation. Medina argues that male and female brains are different. He is careful with it. I am still on the fence — not because the science isn't real, but because I have watched this kind of finding get weaponized into women aren't good at math. That is not what the data says. Different strengths, maybe. Stereotypes, no. I'd rather under-claim here than help a lie travel further.

So: read this book. Get the cheat sheet. Tape it somewhere you'll see it.

In the next decade, the people who learn deliberately — sleep enough, exercise enough, repeat what matters, attend to what matters, stay curious — will have a quiet, compounding advantage. Not because AI is dangerous. Because our brains, untended, will let it do all the lifting. And then we'll have offloaded the one thing that was ours.

— Arun

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Pick up Brain Rules at The Thinking Spot in Minnetonka, or order it from bookshop.org — a portion supports independent booksellers like ours.