Neurotransmitters are a confidence game

by Dorian Minors

January 17, 2022

Analects  |  Newsletter

Excerpt: You might have heard people often talk about the 'reward neurotransmitter' or the 'love hormone' or the 'happiness molecule' and so on. Fact is, although we know about some actions of these neurotransmitters, we actually have very little idea about how those actions play out in actual behaviour.


Neurotransmitters are psychological snake oil. A confidence game pop-psychologists play with their audience. There is frankly no convincing story of human behaviour made more comprehensible by talking about dopamine.

You might have heard people often talk about the ‘reward neurotransmitter’ or the ‘love hormone’ or the ‘happiness molecule’ and so on.

Remarkable stuff—that one molecule in our brain is responsible for making us happy, and another for our social bonding. Almost makes you wonder why we need all this extra stuff in our heads. Molecules are tiny, and our brain takes up so much space. Seems unreasonable. Or perhaps, what’s unreasonable is the idea that these molecules are doing what these people are saying they’re doing.

Fact is, although we know about some actions of these neurotransmitters, we actually have very little idea about how those actions play out in actual behaviour.

For example, serotonin is known as the ‘happiness molecule’. We know it has a relationship to mood. Interesting evidence suggests this is so. For example, we think that the despondent ‘come down’ after taking drugs like MDMA is related to a depletion of serotonin in the brain.

But if you just flood the brain of a depressed person with serotonin, they don’t get happier. The anti-depressant that does this only improves symptoms for something like a third of people. A similar number to simply providing a placebo pill instead. More interestingly, people taking these drugs are more likely to try and kill themselves.

I wouldn’t draw too many conclusions from this, because many other factors are at play there. For example, the placebo effect is far more powerful than most people are willing to grant. And the role of serotonin in humans is confusing enough that it’s produced wild speculations for the longest time. But it certainly means that calling serotonin the ‘happiness molecule’ is overstating the case.

Looking at neurotransmitters to explain human behaviour is something like looking at the dust in the nose of the sneezing person on the 45th floor to determine something about that company’s supply chain. It might be asbestos, making everyone ill and driving down productivity. Or it might just be dust.

Indeed, I’m frankly never quite sure exactly what value neurotransmitters have in actually understanding brain and behaviour better. Only that it makes people feel smarter to say things like ‘doing x thing releases y neurotransmitter which has z psychological benefit’.

I have never once heard a construction like that where the reference to the neurotransmitter was anything more than cosmetic. To say ‘going for a run will trigger a release of dopamine, which will make you feel good’, has precisely the same informational content as ‘going for a run will make you feel good’. Indeed, that’s not even how dopamine works, and I’d be surprised if anyone noticed because including the word dopamine made absolutely zero difference to the sentence’s meaning.

More to the point, I’ve never heard one of these where the link between the neurotransmitter and the benefit was as legitimate as implied. They are psychological snake-oil and should be referred to sparingly, knowing that all one is doing is playing a confidence game with one’s audience.

All anyone really needs to know about neuromodulators, outside of very select circles, is that changes in the concentrations of these molecules across populations of neurons have difficult to understand effects on the way we learn and respond to the world. They mediate how we respond, but talking about them doesn’t particularly help us understand our responses better.

For example, the best known effects are related to simple learning mechanisms. Changes in neuromodulators signal to our neurons that they should change their connections to other neurons. That the neural pathways that exist might need to be updated. You can read about the effects of those changes in these articles on classical and operant conditioning. But notice that nowhere in those articles do I mention neurotransmitters, because it serves no practical purpose to do so.

The only value in stretching those two kinds of learning—operant and classical conditioning—into the brain comes from discovering that we are developing neural pathways that map the statistical structure of the environment we live in and our habitual responses to that environment. Put a different way, that certain perceptions usually have certain consequences, and that often certain responses are best when dealing with those consequences.

This is a level of brain science that we can actually understand when it comes to parsing our behaviour. That our brain helps us to link these causes and consequences together.

Less comprehensible is the idea that somehow, an enormous ecosystem of tiny little molecules are engaging in some uncountable number of transactions every second, all day, changing your brain in miniscule increments to eventually produce a reliable preference for, say, eating when you’re hungry, or hugging your sad companion. These just aren’t sensible levels of comparison.

So, do me a favour. Next time you’re inclined to talk about neurotransmitters, just don’t. And if you hear someone else dropping neuromodulators into the conversation, you might as well just ask upfront how much their e-book is. It’ll save everyone a bunch of time.

This is an adapted extract from Neurotypica: a guide to brain and behaviour

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