The Molecule of More: How a Single Chemical in Your Brain Drives Love, Sex, and Creativity―and Will Determine the Fate of the Human Race

by Daniel Z. Lieberman

Wanting, or desire, flows from an evolutionarily old part of the brain deep inside the skull called the ventral tegmental area. It is rich in dopamine; in fact, it is one of the two main dopamine-producing regions. Like most brain cells, the cells that grow there have long tails that wind through the brain until they reach a place called the nucleus accumbens. When these long-tailed cells are activated, they release dopamine into the nucleus accumbens, driving the feeling we know as motivation. The scientific term for this circuit is the mesolimbic pathway, although it’s easier to simply call it the dopamine desire circuit

This dopamine circuit evolved to promote behaviors that lead to survival and reproduction, or, to put it more plainly, to help us get food and sex, and to win competitions. It’s the desire circuit that’s activated when you see the plate of donuts on the table, and it’s activated not by need, but by the presence of something attractive from an evolutionary or life-sustaining standpoint. That is, at the moment such a thing is seen, the circuit is activated whether or not you’re hungry. That’s the nature of dopamine. It’s always focused on acquiring more of everything with an eye toward providing for the future. Hunger is something that happens here and now, in the present. But dopamine says, “Go ahead and eat the donut, even if you’re not hungry. It will increase your chance of staying alive in the future. Who knows when food will be available next?” That made sense for our evolutionary ancestors, who lived most of their lives on the brink of starvation.

the dopamine system is more or less obsessed with keeping us alive. It constantly scans the environment for new sources of food, shelter, mating opportunities, and other resources that will keep our DNA replicating. When it finds something that’s potentially valuable, dopamine switches on, sending the message Wake up. Pay attention. This is important. It sends this message by creating the feeling of desire, and often excitement. The sensation of wanting is not a choice you make. It is a reaction to the things you encounter.

The desire circuit, powered by dopamine, has sprung into action. She’s going to remember this place where the berry bushes grow. From now on, whenever she sees this bush, a little dopamine will be released to make her more alert and to give her a hint of excitement, the better to motivate her to acquire this thing that can help her stay alive. An important memory has been formed: important because it’s linked to survival, important because it was triggered by the release of dopamine.

saying something is “important” is another way of saying it’s linked to dopamine. Why? Because among the many things it does, dopamine is an early-warning system for the appearance of anything that can help us survive. When something useful to our continued existence appears, we don’t have to think about it. Dopamine makes us want it, right now. It doesn’t matter if we’re going to like it, or if we even need it at the moment. Dopamine doesn’t care. Dopamine is like the little old lady who always buys toilet paper. It doesn’t matter if she has a thousand rolls stacked in the pantry. Her attitude is you can never have too much toilet paper. So it is with dopamine, but instead of toilet paper, dopamine urges you to possess and accumulate anything that might help keep you alive.

it also explains more nuanced things; for instance, why we remember some names but not others. There are all sorts of tricks one can use to make remembering easier, such as using the person’s name in conversation a few times. But even if the name seems committed to memory, it almost always fades quickly. Important names—those of people who can affect our lives—are easier. The name of the person who flirted with you at the party will stay in your memory longer than the name of the person who ignored you. So will the name of the man who told you to set up an appointment to see him because he wants to give you a job—and his name will stick with you even more reliably if you’re unemployed. Similarly, male rats remember the correct route through a maze more easily if there is a sexually receptive female at the other end.

some people spend the majority of their lives pursuing this feeling—a feeling of anticipation, a feeling that life is about to get better. You’re about to eat a delicious dinner, see an old friend, make a big sale, or receive a prestigious award. Dopamine turns on the imagination, producing visions of a rosy future.

What happens when the future becomes the present—when the dinner is in your mouth or your lover is in your arms? The feelings of excitement, enthusiasm, and energy dissipate. Dopamine has shut down. Dopamine circuits don’t process experience in the real world, only imaginary future possibilities. For many people it’s a letdown. They’re so attached to dopaminergic stimulation that they flee the present and take refuge in the comfortable world of their own imagination. “What will we do tomorrow?” they ask themselves as they chew their food, oblivious to the fact that they’re not even noticing this meal they had so eagerly anticipated. To travel hopefully is better than to arrive is the motto of the dopamine enthusiast.

Dopamine circuits don’t process experience in the real world, only imaginary future possibilities. For many people it’s a letdown. They’re so attached to dopaminergic stimulation that they flee the present and take refuge in the comfortable world of their own imagination. “What will we do tomorrow?” they ask themselves as they chew their food, oblivious to the fact that they’re not even noticing this meal they had ...

The future isn’t real. It’s made up of a bundle of possibilities that exist only in our minds. Those possibilities tend to be idealized—we usually don’t imagine a mediocre outcome. We tend to think about the best of all possible worlds, and that makes the future more attractive. On the other hand, the present is real. It’s concrete. It’s experienced, not imagined, and that requires a different set of brain chemicals—the H&Ns, the here-and-now neurotransmitters. Dopamine makes us want things with a passion, but it’s the H&Ns that allow us to apprecia...

The transition from excitement to enjoyment can be challenging. Think of buyer’s remorse, the sense of regret that occurs after making a big purchase. Traditionally it has been attributed to the fear of having made the wrong choice, guilt over extravagance, or a suspicion of having been too influenced by the seller. In fact, it’s an example of the desire circuit breaking its promise. It told you that if you bought that expensive car you’d be overcome with joy, and your life would never be the same. Except, once you became its owner, those feelings were neither as intense nor as long lasting as you had hoped. The desire circuit often breaks its promises—which is bound to happen, because it plays no role in generating feelings of satisfaction. It is in no position to make dreams come true. The desire circuit is, so to speak, just a salesman.

Buyer’s remorse is the failure of the H&N experience to compensate for the loss of dopaminergic arousal.

Thus we see three possible solutions to buyer’s remorse: (1) chase the dopamine high by buying more, (2) avoid the dopamine crash by buying less, or (3) strengthen the ability to transition from dopamine desire to H&N liking.

In no case, though, is there any guarantee that the things we so desperately want will be things that we will enjoy having. Wanting and liking are produced by two different systems in the brain, so we often don’t like the things we want.

Like a guided missile, addictive drugs hit the desire circuit with an intense chemical blast. No natural behavior can match that. Not food, not sex, not anything.

The dopamine system evolved to motivate us to survive and reproduce. For most people there is nothing more important than staying alive and keeping their children safe. These are the activities that produce the largest dopamine surges. In a very literal way, large dopamine surges signal the need to react to life-and-death situations. Take shelter. Find food. Protect your children. These are tasks that hit the dopamine system hard. What could be more important?

An addict chooses drugs over work, family, everything. You think he’s making irrational choices but his brain is telling him that his choices are perfectly logical. If someone offered you a choice between a meal at a nice restaurant, even the nicest restaurant in town, and a check for million dollars, it’s ridiculous to think you’d choose dinner. That’s exactly how an addict feels when choosing between, say, paying the rent and buying crack. He chooses the one that will lead to the bigger dopamine hit. The euphoria of crack cocaine is bigger than just about any experience you can name. That’s rational from the point of view of desire dopamine, which is what drives the behavior of addicts.

Drugs are fundamentally different from natural dopamine triggers. When we’re starving, there’s nothing more motivating than getting food. But after we eat, the motivation for getting food declines because satiety circuits become active and shut down the desire circuit. There are checks and balances in place to keep everything stable. But there’s no satiety circuit for crack. Addicts take drugs until they pass out, get sick, or run out of money. If you ask an addict how much crack he wants, there is only one answer: more.

The goal of the dopamine system is to predict the future and, when an unexpected reward occurs, to send a signal that says, “Pay attention. It’s time to learn something new about the world.” In this way, circuits bathed in dopamine become malleable. They morph into new patterns. New memories are laid down, new connections are established. “Remember what happened,” says the dopamine circuit. “This may be useful in the future.”

no longer any reward prediction error. Dopamine is not meant to be an enduring reservoir of joy. By shaping the brain to make surprising events predictable, dopamine maximizes resources, as it is supposed to do, but in the process, by eliminating surprise and extinguishing reward-prediction error, it suppresses its own activity.

Drugs destroy the delicate balance that the brain needs to function normally. Drugs stimulate dopamine release no matter what kind of situation the user is in. That confuses the brain, and it begins to connect drug use to everything. After a while, the brain becomes convinced that drugs are the answer to all aspects of life. Feel like celebrating? Use drugs. Feeling sad? Use drugs. Hanging out with a friend? Use drugs. Feeling stressed, bored, relaxed, tense, angry, powerful, resentful, tired, energetic? Use drugs. People in twelve-step programs such as Alcoholics Anonymous say that addicts need to watch out for three things that might trigger craving and topple them into relapse: people, places, and things.

So nouns trigger cravings?

The ability to trigger dopamine in the desire circuit is what makes a drug addictive. Alcohol does it, heroin does it, cocaine does it, even marijuana does it. Not all drugs trigger dopamine to the same degree, though. The ones that hit dopamine the hardest are more addictive than ones that are more restrained. By triggering the release of more dopamine, the “hard hitters” also make the user feel more euphoric, and stimulate the most intense craving when the drug is gone. Intensity varies by drug. Pot smokers are generally less desperate to get more of the drug than cocaine addicts. But beneath all the differences is the commonality of the dopaminergic rush and subsequent craving.

the crack cocaine that users smoke is essentially the same molecule as powder cocaine that users snort, but crack is far more addictive—so much so that when crack became widely available in the 1980s, it took the world of recreational drug use by storm. What’s so “great” about crack that allowed it to take over the cocaine market, and chemically enslave thousands of people? From a scientific perspective, the answer is simple: the rate of onset of action.

That’s why smoking crack is more appealing than snorting powder cocaine: smoking produces a faster, larger dopamine rush. Regular cocaine can’t be smoked; the heat destroys it. Transforming it into crack makes it smokable, so the drug gets in the body through the lungs instead of the nose. That makes a big difference.

When powdered cocaine flies up into the nose, it lands on the nasal mucosa, the red lining inside your nose. It’s red because the blood vessels are at the surface. Cocaine enters the bloodstream through these vessels, but it’s not very efficient; there isn’t much room available in there. Sometimes when a user snorts a line of cocaine, some of the powder never makes it into their system because there’s not enough space for it on the surface of the mucosa.

Smoking cocaine as crack makes the process more efficient. Unlike the nasal mucosa, the surface area of the lungs is huge. Filled with hundreds of millions of tiny air sacs, the surface area is equal to one side of a tennis court. There’s plenty of room there, and when the vaporized cocaine hits the lungs, it goes right into the bloodstream and up to the brain. It’s a steep slope—a sudden burst—and a big hit to the dopamine system.

The link between a rapidly rising blood level and dopamine release is also why addicts progress to injecting drugs into their veins. Other routes of administration no longer give them the thrill they’re after. Injecting drugs is scary, though, and is a clear sign of an addict, so the stigma and fear of the needle may stop many of them from progressing further. Unfortunately, smoking gets the drug into the brain about as fast as intravenous injection. Smoking also lacks the stigma associated with needles. As a result, many would-be casual users of cocaine progress to life-destroying addiction. The same thing happened with methamphetamine when it became available in smokable form.

Patrick Kennedy,

There’s no partying there. There’s no enjoyment. This is about relieving the pain. People have this mistaken notion that you get high. What you’re really getting is relief from the low.

This is why, even if an addict uses so much cocaine (or heroin or alcohol or marijuana) that it no longer leads to feeling high, he will continue to use it.

When an expected reward fails to materialize, the dopamine system shuts down. In scientific terms, when the dopamine system is at rest, it fires at a leisurely three to five times per second. When it’s excited, it zooms up to twenty to thirty times per second. When an expected reward fails to materialize, the dopamine firing rate drops to zero, and that feels terrible. That’s why a dopamine shutdown makes you feel resentful and deprived. It’s how a recovering drug addict feels every day as he struggles to get clean and sober. It takes an enormous amount of strength, determination, and support to overcome addiction. Don’t mess with dopamine. It hits back hard.

Giving in to craving doesn’t necessarily lead to pleasure because wanting is different from liking. Dopamine makes promises that it is in no position to keep.

In an interview with The Economist, Dr. Berridge noted that the dopamine desire system is powerful and highly influential in the brain, whereas the liking circuit is tiny, fragile, and much harder to trigger. The difference between the two is the reason that “life’s intense pleasures are less frequent and less sustained than intense desire.”

liking relies on the same chemicals that promote the long-term satisfaction of companionate love: endorphins and endocannabinoids. Because opioid drugs such as heroin and OxyContin scramble both the desire circuit and the liking circuit (where dopamine acts and where endorphin acts), they are among the most addictive drugs there are. Marijuana is similar. It also interacts with both circuits, stimulating dopamine as well as the endocannabinoid system. This dual effect leads to unusual results.

Boosting dopamine can lead to enthusiastic engagement with things that would otherwise be perceived as unimportant. For example, marijuana users have been known to stand in front of a sink, watching water drip from the faucet, captivated by the otherwise mundane sight of the drops falling over and over again. The dopamine-boosting effect is also evident when marijuana smokers get lost in their own thoughts, floating aimlessly through imaginary worlds of their own creation. On the other hand, in some situations marijuana suppresses dopamine, mimicking what H&N molecules tend to do. In that case, activities that would typically be associated with wanting and motivation, such as going to work, studying, or taking a shower, seem less important.

Drugs that boost dopamine can also boost impulsive behavior. A cocaine addict once said, “When I do a line of cocaine, I feel like a new man. And the first thing that new man wants is another line of cocaine.” When the addict stimulates his dopamine system, his dopamine system responds by demanding more stimulation. That’s why most cocaine addicts smoke cigarettes when they use cocaine. Like cocaine, nicotine stimulates additional dopamine release, but it’s cheaper and easier to get.

Nicotine, in fact, is an unusual drug because it does very little except trigger compulsive use. According to researcher Roland R. Griffiths, PhD, professor of psychiatry and behavioral sciences at the Johns Hopkins University School of Medicine, “When you give people nicotine for the first time, most people don’t like it. It’s different from many other addictive drugs, for which most people say they enjoy the first experience and would try it again.” Nicotine doesn’t make you high like marijuana or intoxicated like alcohol or wired up like speed. Some people say it makes them feel more relaxed or more alert, but really, the main thing it does is relieve cravings for itself. It’s the perfect circle. The only point of smoking cigarettes is to get addicted so one can experience the pleasure of relieving the unpleasant feeling of craving, like a man who carries around a rock all day because it feels so good when he puts it down.

Addiction is not a sign of weak character or a lack of willpower. It occurs when the desire circuits get thrown into a pathological state by overstimulation. Prod dopamine too hard and too long, and its power comes roaring out. Once it has taken charge of a life, it is difficult to tame.

Recreational drugs aren’t the only ones that stimulate dopamine. There are prescription drugs that do it as well, and when they hit the desire circuit too hard, strange things can happen. Parkinson’s disease is an illness of dopamine deficiency in a pathway that’s responsible for controlling muscle movements. Or, to put it more simply, it’s how we translate our inner world of ideas into action, the way we impose our will upon the world. When there is not enough dopamine in this circuit, people become stiff and shaky, and they move slowly. The treatment is to prescribe drugs that boost dopamine.

Most people who take these drugs do just fine, but about one in six patients gets into trouble with high-risk, pleasure-seeking behavior. Pathological gambling, hypersexuality, and compulsive shopping are the most common ways the excessive dopamine stimulation is seen.

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After they took the pills, the volunteers were given the opportunity to gamble. The researchers found that the participants who took the dopamine-boosting pill placed larger and riskier bets than those who took the placebo. The effect was more pronounced in men than in women. The researchers periodically asked the participants to rate how happy they were. There was no difference between the two groups. The enhanced dopamine circuit boosted impulsive behavior, but not satisfaction—it boosted the wanting, but not the liking.

the more active the dopamine cells were, the more money the volunteers expected to win.

When it comes to addiction, easy access matters. More people get addicted to cigarettes and alcohol than to heroin, even though heroin hits the brain in a way that is more likely to trigger addiction. Cigarettes and alcohol are a larger public health problem because they are so easy to obtain. In fact, the most effective way to reduce the problems caused by these substances is to make it more difficult to get them. We’ve all seen “quit smoking” advertisements on buses and subways. They don’t work. We’ve heard about school programs that teach kids to say no to drugs and alcohol. In many cases drug and alcohol use go up after these programs because they pique the curiosity of the adolescent students. The only thing that has been shown to work consistently is raising taxes on these products and placing limits on where and when they can be sold. When these measures are taken, use goes down.

We don’t yet know if compulsive viewing of pornography is exactly the same as drug addiction, but they have things in common. As with drug addiction, people who become trapped in a cycle of excessive pornography use spend more and more time pursuing this activity—sometimes many hours every day. They abandon other activities so they can focus on adult internet sites. Sexual relations with their partners tend to become less frequent and less satisfying. One young man gave up dating completely. He said that he’d rather look at pornography than go out with a real woman because the women in the pictures never demanded anything of him, and never said no.

As with drugs, habituation can also occur with pornography, in which the starting “dose” no longer works as well. When sex addicts were repeatedly shown the same sexual images, their interest diminished. The activity measured in their dopamine circuits also decreased as the images were shown over and over. The same thing happened to healthy males who were repeatedly shown the same pornographic video. When they were shown a new video, their dopamine systems revved up again. This experience of a dopamine rush, followed by a dopamine drop (repeated images), followed by another dopamine rush (new images), pushes addicts to continually seek out fresh material, which may explain why browsing internet sex sites can become compulsive. It’s hard to resist the demands of dopamine circuits, especially with something as evolutionarily important as sex.

Douglas Gentile

nearly one in ten gamers ages eight to eighteen are addicted, causing family, social, school, or psychological damage because of their video game playing habits—a rate of addiction more than five times higher than that among gamblers,

Video games are more complex than slot machines, so there are more opportunities for programmers to bake in features that trigger dopamine release in order to make it hard to stop playing. Video games are all about imagination. They immerse us in a world where our fantasies can come true, where reality-shunning dopamine can bask in endless possibilities. We can explore environments that constantly change, ensuring that the surprises never end. We may start off in the desert, progress to a rain forest, then a dark alley in a gritty urban hell, then suddenly we’re on a rocket, hurtling toward an alien world. Players do more than just explore, though. Video games are about progress. They’re about making the future better than the present. Gamers progress through levels while increasing their strength and abilities. It’s a dopamine dream come true. To keep progress front and center in a gamer’s mind, the screen constantly displays the accumulating points or growing progress bars so players never forget. They have to keep pursuing more.

Tom Chatfield,