The key ideas

The Molecule of More

Daniel Z. Lieberman, Michael E. Long, 2018

The rats kept eating with gusto, yet the “pleasure molecule” in their brains fell quiet. Why? A psychiatrist and a writer explain how dopamine is tied to anticipation, falling in love, addiction and creativity. A lively popular science model, with an honest caveat that the brain is more complex than a single molecule.

Who it is for

For anyone who has noticed that the things they wanted quickly stop bringing joy, and who wants to understand why the brain works this way.

Dopamine, after all, is not the pleasure molecule. It is the anticipation molecule.

What the book is about

Look down. There you see what you can reach with your hand: a desk, a cup, a phone. Now look up, out the window. Out there is everything you have to walk to, plan for and work to get.

The psychiatrist Daniel Lieberman and the writer Michael Long believe the brain treats these two worlds differently. In their model, what is distant and in the future is run by one substance, dopamine. That is why they call it “the molecule of more.”

Ahead: rats that kept eating with gusto while their dopamine stayed silent; a monkey and a light bulb; a couple whose passion faded; and a slot machine that grew out of an experiment with a pigeon.

An important frame. The authors warn you themselves: they simplify a great deal, and the later chapters are speculative in places. Real dopamine is more complex than “the molecule of more”: it is involved in movement and in learning too. This is a popular science model, not a medical guide.

Idea 1. The pleasure molecule that went quiet

Dopamine in the brain was discovered in 1957 by Kathleen Montagu, a researcher at a hospital laboratory near London. Very few cells produce it, about one in two million according to the authors. But, they say, these cells have an outsized effect on behavior.

At first, dopamine was nicknamed the pleasure molecule: in experiments with cocaine, the harder the dopamine pathway worked, the stronger the high. Then the cocaine was replaced with food. Rats with electrodes in their brains were given food pellets, and their dopamine cells lit up.

But the scientists kept the experiment going. Day after day, food dropped into the cage. The rats ate with the same appetite. And the dopamine went quiet. Why did the pleasure remain while the “pleasure molecule” fell silent?

The first sip of coffee at a new café feels like an event. A month later, the same coffee is just part of the morning.

If a substance goes quiet while the pleasure continues, it is probably responsible for something else. The answer came from an experiment with a monkey.

Read in Livria

About the author

Daniel Lieberman is an American psychiatrist at George Washington University. Michael Long is a writer who teaches at Georgetown University. Long later released a follow-up, a practical guide called Taming the Molecule of More.

All books by this author: Daniel Z. Lieberman, Michael E. Long

Terms from the book

  • Dopamine
  • Companionate love
  • Reward prediction error: The difference between what we got and what we expected. Wolfram Schultz's research showed that dopamine cells respond to this difference.
  • Here and now molecules: The authors' term, not a scientific category: serotonin, oxytocin, endorphins and endocannabinoids, which in their model are tied to experiencing the present.
  • Desire circuit: In the authors' model, the dopamine pathway tied to craving, enthusiasm and anticipation.
  • Control circuit: In the authors' model, the dopamine pathway to the frontal lobes, tied to planning, calculation and effort toward a distant goal.

All terms

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