Dopamine: the “wanting” molecule

Dopamine's role in reward prediction and motivation is one of the most solid findings in neuroscience, although it has many functions that are still being researched.

Sound familiar?

You swipe through one video after another. Most of them don't interest you, but you keep going. Why? Because your brain is waiting for the next video that will actually be worth it.

What it is

Dopamine is a neurotransmitter, a substance neurons use to communicate. On social media it's often called "the happiness hormone" or "the pleasure hormone", but neuroscience paints a more interesting picture: dopamine has more to do with learning what's worth pursuing and wanting to get it than with enjoying it.

The experiment

In the 1990s, neuroscientist Wolfram Schultz recorded the activity of dopamine neurons in monkeys as they received drops of juice.¹

When the juice arrived unexpectedly, the neurons fired strongly.
Once the monkeys learned that a signal (a light, a sound) announced the juice, the neurons started firing at the signal, not at the juice.
And if the signal appeared but no juice came, their activity dropped below normal.

The conclusion: dopamine works as a prediction error signal, "this is better (or worse) than I expected". It's a way of learning what to seek out.

What we know today

Kent Berridge and Terry Robinson showed that we need to distinguish between "wanting" and "liking".² Rats with severely depleted dopamine still showed signs of enjoyment when tasting something sweet, but wouldn't make an effort to get it. Dopamine was needed for "wanting", not for "liking".

Pleasure itself seems to depend on other brain systems, such as small areas called "hedonic hotspots" that use other substances, like the brain's natural opioids.³

Myth vs. reality

Myth "Dopamine is the pleasure hormone."

Reality Dopamine drives desire and motivation more than enjoyment. That's why we can badly "want" something that doesn't end up making us feel that good.

In everyday life

Unpredictable rewards tend to hook us more: notifications and scrolling exploit the fact that you don't know when something interesting will turn up.
Tell wanting from enjoying: do you really like what you're doing, or do you just feel the urge to keep going?

Sources

Schultz, W., Dayan, P., & Montague, P. R. (1997). A neural substrate of prediction and reward. Science, 275(5306), 1593–1599. doi.org/10.1126/science.275.5306.1593
Berridge, K. C., & Robinson, T. E. (1998). What is the role of dopamine in reward: Hedonic impact, reward learning, or incentive salience? Brain Research Reviews, 28(3), 309–369. doi.org/10.1016/S0165-0173(98)00019-8
Berridge, K. C., & Kringelbach, M. L. (2015). Pleasure systems in the brain. Neuron, 86(3), 646–664. doi.org/10.1016/j.neuron.2015.02.018