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

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.” What’s the end result? You don’t get surprised the next time the reward occurs. When you discovered the website that streamed your favorite music, it was exciting. But the next time you visited the site it wasn’t. There’s 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.

But addictive drugs are so powerful that they bypass the complicated circuitry of surprise and prediction and ...

sy...

In this way, they scramble everything up. All that’s left is a gnaw...

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...

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 mak...

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 happ...

An evening of drinking feels best at the start. The level of alcohol is rising rapidly, and that feels good—it’s dopaminergic euphoria, directly related to how fast the alcohol gets into the brain. As the night goes on, though, the rate of increase slows down, and dopamine turns off. Euphoria gives way to drunkenness. The early stage of rising levels of alcohol might be characterized by increased energy, excitement, and pleasure. Intoxication, on the other hand, is characterized by sedation, poor coordination, slurred

speech, and bad judgment.

The speed with which alcohol gets into the brain determines how high a drinker feels. It’s the total amount of alcohol consumed, regardless of whether it’s fast or sl...

Inexperienced drinkers get the two confused. They start drinking, push their blood alcohol level up, and experience the pleasures of dopamine release, then mistakenly believe that the pleasure is the pleasure of intoxication. So they keep drinking more and more, trying in vain to get the rush back. It ends badly, often bent over a toilet.

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.

You were walking along expecting nothing, something good appeared, and your dopamine system leaped into action—hence your “prediction” was wrong, and you experienced the burst of dopamine from reward prediction error.

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.

Dopamine makes promises that it is in no position to keep. “If you buy these shoes, your life will change,”

Dr. Kent Berridge, a professor of psychology and neuroscience at the University of Michigan, is a pioneering figure in the process of disentangling dopamine desire circuits from here-and-now liking circuits. He found that when a rat tastes a sugar solution, it signals liking by licking its lips. In contrast, it expresses wanting by consuming more of the sweet liquid. When he injected a chemical into a rat’s brain that boosted dopamine, it consumed more sugar water, but

didn’t show any increased signs of liking. On the other hand, when he injected an H&N booster, he was able to triple the lip-smacking liking response. All of a sudden the sugar water became far more delicious.

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 inte...

Liking involves different circuits in the brain, and uses the H&N chemicals, not dopamine, to send messages. In particular, 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 Ox...

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 endocannabinoi...

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 c...

In 2015 the Daily Mail claimed that as many as one in twenty-five young adults in the United Kingdom were believed to be sex addicts.

In researching this problem, psychologist Douglas Gentile of Iowa State University found that 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, according to the National Research Council on Pathological Gambling.

So, what do the data tell us about the ideal portion of treasure chests that should contain gems? It turns out that 25 percent is the magic number. That’s what keeps people playing the longest. And there’s no reason why the other 75 percent should be empty. Game developers put low-value rewards in the non-gem chests so every single one will contain a surprise.

Americans spend more than $20 billion per year on video games; they spent only half that much on movie tickets in 2016, the biggest U.S. box office year in history.

DOPAMINE VERSUS DOPAMINE It’s natural to confuse wanting and liking. It seems obvious that we would want the things that we will like having. That’s how it would work if we were rational creatures, and despite all

evidence to the contrary, we persist in thinking that we are rational creatures. But we’re not. Frequently we want things that we don’t like. Our desires can lead us toward things that may destroy our lives, such as drugs, gambling, and other out-of-control behaviors. The dopamine desire circuit is powerful. It focuses attention, motivates, and thrills. It has a profound influence over the choices we make. Yet it isn’t all-powerful. Addicts get clean. Dieters lose weight. Sometimes we switch off the TV, get off the couch, and go for a run. What kind of circuit in the brain is powerful enou...

You may recall that in many situations, future-focused dopamine opposes the activity of the H&N circuits and vice versa. If you’re thinking about where to go for dinner, you’re probably no...

sandwich you’re eating for lunch. But there’s also opposition within the future-oriented dopamine system itself. Why would the brain develop circuits that work against each other? Wouldn’t it make more sense to have everyone pulling together, so to speak? In fact, no. Systems that contain opposing forces are easier to control. That’s why cars hav...

Not surprisingly, the dopamine control circuit involves the frontal lobes, the part of the brain that is sometimes called the neocortex because it evolved most recently. It’s what makes human beings unique. It gives us the imagination to project ourselves further into the future than the desire circuit can take us, so we can make long-term plans. It’s also the part that allows us to maximize resources in that future by creating...

language, mathematics, and science. It’s intensely rational. It doesn’t feel, because emotion is an H&N phenomenon. As we will see in the next chapter, it’s cold, calculating, and ru...

How far will you go? In which dopamine drives us to overcome complexity, adversity, emotion, and pain so we can control our environment.

Desire dopamine makes us want things. It is the source of raw desire: give me more. But we’re not at the ungoverned mercy of our desire. We also have a complementary dopamine circuit that calculates what sort of more is worth having. It gives us the ability to construct plans—to strategize and dominate the world around us to get the things we want. How does a single chemical do both things? Think of rocket fuel that powers the main engines of a spaceship. The same fuel that pushes the rocket forward can be redirected to drive directional thrusters to steer the ship, as well as retrorockets to slow it down. It all depends on the path the fuel takes before it’s ignited—different functions, but all working together to get the spaceship to its destination. In a similar way, dopamine moving through different brain circuits yields different functions, too, and toward a common end: a relentless focus on enhancing the future.

Urges come from dopamine passing through the mesolimbic circuit, which we call the dopamine desire circuit. Calculation and planning—the means of dominating situations—come from the mesocortical circuit, which we will call the dopamine control circuit (Figure 3). Why call it the control circuit? Because its purpose is to manage the uncontrolled urges of desire dopamine, to take that raw energy and guide it toward profitable ends. Also, by using abstract concepts and forward-looking strategies, it allows us to gain control over the world around us, and dominate our environment.

In addition, the dopamine control circuit is the source of imagination. It lets us peer into the future to see the consequences of decisions we might make right now, and thus allows us to choose which future we prefer. Finally, it gives us the ability to plan how to make that imaginary future a reality.

Like the desire circuit, which only

cares about things we do not have, control dopamine works in the unreal world of the possible. The two circuits begin in the same place, but the desire circuit ends in a part of the brain that triggers excitement and enthusiasm, while the control circuit goes to the f...

In this way, both circuits give us the capacity to consider “phantoms”—things that don’t physically exist. For desire dopamine, those phantoms are things we wish to have but don’t have right now—things we want in the future. For control dopamine, the phantoms are the building blocks of imagination and creative thought: ideas, p...

Control dopamine carries us beyond the primitive I want of desire dopamine. It gives us tools to comprehend, analyze, and model the world around us, so we can extrapolate possibilit...

achieve our goals. It is an extended and complex execution of the evolutionary imperative: to secure ...

In contrast, desire dopamine is the kid in the back seat shouting for his parents to “Look! Look!” every time he sees a McDonald’s, a toy store, or a puppy on the sidewalk. Control dopamine is the parent at the wheel, hearing each request and considering whether it’s worth stopping for—and deciding what to do if he pulls over. Control dopamine takes the excitement and motivation prov...

Dopamine encourages us to maximize our resources by rewarding us when we do so—the act of doing something well, of making our future a better, safer place, gives us a little dopamine “buzz.”

The entrepreneur who develops the next killer technology in his garage is often surprised to find that the world isn’t beating a path to his door. Success takes years of hard work and so many revisions to the original idea that it’s barely recognizable by the time it gets to market. It’s not enough to just imagine the future. To bring an idea to fruition we must struggle with the uncompromising realities of the physical world. We need not only knowledge but also tenacity. Dopamine, the chemical of future success, is there to deliver.