How Dopamine Actually Works (and How to Use It)
By: Brian Hoeflinger, MD
August 23, 2026 | #91
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Disclaimer: Opinions are my own. Not medical advice.
Medical Trivia of the Week
You stay in the bath too long and your fingertips wrinkle. What actually causes it? (the correct answer is at the end of this email)
- A) The skin soaks up water and swells
- B) The oils that protect the skin wash away
- C) Your nervous system narrows the blood vessels in your fingertips
- D) Warm water expands the outer layer of skin
In Today's Newsletter
- Almost everything you have heard about dopamine is wrong. It is not the pleasure chemical.
- It is a prediction chemical. Once you understand what it is actually measuring, a lot of ordinary life starts to make sense.
- I'll walk you through what the research shows, then give you five ways to use it starting today.
The Chemical Everyone Gets Wrong
If you have heard of dopamine at all, you have probably heard it called the pleasure chemical. Something good happens, dopamine floods your brain, you feel happy.
That is not actually what dopamine does.
Dopamine is about prediction, not pleasure. It fires hardest when something turns out better than you expected. Once you see that difference, a surprising amount of everyday life starts to make sense.
The Experiment That Changed Everything
In 1997, three researchers published a paper in Science that reshaped how we think about reward.
They recorded from single dopamine neurons in monkeys receiving a small drop of fruit juice. At first the juice arrived with no warning, and the neurons fired hard.
Then the researchers added a light before the juice. Same light, same juice, over and over, for days.
Here is where it gets interesting. Once the monkey learned that the light meant juice was coming, the dopamine neurons stopped firing at the juice. They fired at the light instead.
The reward had not changed. The taste had not changed. But the dopamine had moved backward in time, off the reward and onto the signal that predicted it.
Then they showed the light and withheld the juice. At the exact moment it should have arrived, the neurons went silent, dropping below their normal resting rate.
So the pattern is this. Dopamine goes up when things are better than predicted, does nothing when things go exactly as predicted, and goes down when things are worse than predicted.
That is not a pleasure signal. That is an error signal. Your brain is constantly making predictions, and dopamine reports the gap.
Why This Explains So Much
Once you understand that, several everyday mysteries dissolve.
Why anticipation so often beats arrival. The signal moves to the cue. Planning the trip, seeing it on the calendar, packing the car. That anticipation is not a lesser version of the experience. In your brain, it may be the peak of it.
Why the second cookie is worse than the first. Once your brain fully predicts the reward, the signal fades. Nothing about the cookie changed. Your prediction did. It is also why chasing a bigger version of yesterday's reward is a losing strategy. The target moves every time you reach it.
Why the raise stopped feeling like a raise. You adjusted. The new number became the expectation, and expectations generate no signal.
Wanting and Liking Are Not the Same Thing
Here is another interesting finding from a different lab.
Two researchers at the University of Michigan set out to prove that dopamine caused pleasure. They removed nearly all the dopamine from the brains of rats and expected the animals to stop enjoying sugar.
The rats stopped seeking food entirely. But when sugar was placed directly in their mouths, their pleasure reactions were completely normal.
They still liked it. They simply no longer wanted it.
That result has held up for decades. In people, blocking dopamine reduces the craving for a drug without reducing how pleasant the drug actually feels. The brain runs two separate systems: a large, powerful wanting system that depends on dopamine, and a much smaller, more fragile liking system that does not.
So you can want something intensely that you do not actually enjoy. Not as a figure of speech. As a matter of separate wiring.
Everyone has felt this. You reach for the phone. You scroll. Twenty minutes later you feel worse, not better. The wanting was real. The liking never showed up.
Why Uncertainty Is the Hook
One more piece, from a 2003 study by the team behind that juice experiment.
They trained monkeys with signals indicating different odds that juice would follow. Sometimes a sure thing. Sometimes a coin flip. Sometimes nothing.
The prediction signal behaved as expected. But they found something nobody had seen before. When the outcome was a coin flip, dopamine did not just spike and stop. It climbed steadily through the whole wait, peaking right at the moment of truth. That climb was largest at fifty-fifty odds and vanished entirely when the outcome was certain, either way.
Read that again. Your brain produces the most dopamine not when a reward is guaranteed, but when it might happen.
The researchers pointed out the implication themselves. This may be much of why gambling grips people who know full well the odds are against them.
It is also the architecture of a slot machine, a scratch ticket, and the pull-to-refresh on your phone. You do not check because you expect something good. You check because there might be something good. That maybe is the entire engine.
What This Research Can and Cannot Tell Us
One caveat in all this. These findings come from recordings in monkeys and rats. That is the only way to measure single neurons directly, which is why the work is so precise. Human studies using brain imaging and dopamine-blocking medications point the same direction, but measure the system far more crudely.
So the mechanism is well established. Applying it to your Tuesday afternoon is reasonable inference, not proven fact. I think the inference is sound.
Five Ways to Use This
1. Protect the anticipation.
If the dopamine lives in the cue, then waiting is part of the reward rather than an obstacle to it. Put things on the calendar further out and let yourself look forward to them. A trip booked in March and taken in June gives you three months of signal plus the trip. Booked last minute, you get the trip.
2. Lower the expectation, not the experience.
Dopamine tracks the gap between what you got and what you predicted, which makes your expectation a dial you actually control. Walking in expecting less genuinely produces more. That is not resignation and it is not positive thinking. It is arithmetic.
3. Space things out instead of stacking them.
A fully predicted reward produces no signal. So the coffee you have every morning at the same time in the same chair has quietly stopped registering. Change something. Skip a day. Move it. Variety is not indulgence, it is what keeps the signal alive.
4. Move the cue, not your willpower.
Wanting is triggered by cues, and cues are physical objects in physical places. The phone on the nightstand. The bowl on the counter. Fighting an urge means fighting your strongest system with your weakest. Putting the object out of sight is not weakness. It is using the mechanism the way it works.
5. Ask the liking question.
This is the most useful one. After you do the thing you felt pulled toward, ask yourself one question.
Did I actually enjoy that?
Sometimes the answer is yes. Good. Keep it. Sometimes it is no. And if it is consistently no, you have just located a place where wanting and liking have come apart in your own life. That is worth knowing, and it is worth doing something about.
The Part Worth Remembering
Dopamine is not a happiness chemical, and chasing it is the wrong goal. It is a teaching signal. It evolved to point you toward things worth learning about, in a world where food was scarce and information was hard to come by.
We now live in a world engineered to trigger that signal on purpose, constantly, at a scale it was never built for.
You cannot turn it off, and you would not want to. It is the same machinery that makes you curious, gets you out of bed, and makes you care about anything at all.
But you can stop mistaking wanting for liking. That one distinction, applied honestly, will tell you more about how to spend your days than almost anything else I know.
Impactful Quote of the Week
"There are two tragedies in life. One is to lose your heart's desire. The other is to gain it."
- George Bernard Shaw
All my best,
Brian Hoeflinger
P.S. - Please reply to this email and let me know what you thought of the newsletter or what future topics you would like me to cover. I strive to read and reply to as many as I can.
Medical Trivia Answer:
The correct answer is C) Your nervous system narrows the blood vessels in your fingertips
It is not swelling. It is an active response. A little water gets into the sweat ducts, your nerves signal the small blood vessels in the fingertip to tighten, the tissue underneath loses volume, and the skin on top buckles into folds.
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*Disclaimer: This newsletter and blog is for general informational purposes only and does not constitute the practice of medicine, nursing, or other professional health care services, including the giving of medical advice, and no doctor/patient relationship is formed. The use of information on this newsletter and blog or materials linked from this newsletter and blog is at the user’s own risk. The content of this newsletter and blog is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Users should not disregard or delay seeking medical advice for any medical condition they may have and should consult their healthcare professionals for any such conditions.
