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

When scientists performed brain scans during wagering experiments, they naturally looked at dopamine first. They found that neural activity in the desire circuit increased after wins and decreased after losses—as would be expected. But the changes weren’t symmetrical. The magnitude of the decrease after losses was larger than the increase after gains. The dopamine circuit was mirroring the subjective experience. The effect of loss was greater than the effect of gain.

Experiments of nature are illnesses and injuries that reveal important pieces of scientific knowledge. They are fascinating because they usually represent “experiments” that would be grossly unethical for a scientist to carry out. No one’s going to ask a surgeon to open up a person’s head and cut out their amygdala. But once in a while it happens on its own. In this case, scientists studied two patients who had Urbach–Wiethe disease, a rare condition that destroys the amygdala on both sides of the brain. When these individuals were presented with wagers, they attached equal weight to gain and loss. Without the amygdala, loss aversion vanished. In

Gain is about a better future, so only dopamine is involved. The possibility of gain gets a +1 from dopamine. It gets zero from H&N, because H&N is only concerned with the present. Loss

is also about the future, so it concerns dopamine, and gets a –1. Loss concerns H&N, too, because it affects things in our possession right now. So H&N gives it a –1. Put them together, and gain = +1, loss = –2, exactly wh...

Fear, like desire, is primarily a future concept—dopamine’s realm. But the H&N system gives a boost to the pain of loss in the form of amygdala activation, tipping our judgment when we have ...

Arousal is sometimes used to describe sexual excitement, but more broadly it’s a measure of how engaged a person is with what’s going on around him. When a person is interested and engaged, his heart beats a little faster, his blood pressure goes up a bit, and small amounts of perspiration are released from his sweat glands. Doctors call this a sympathetic response. The

joked that during election season, bathroom signs that say “Employees must wash hands before returning to work” are billboards for the Republican Party.

the logical approach is to kill one person to save five, whereas the harm-aversion approach is to refuse to take someone’s life for the benefit of other people. Using drugs to influence these decisions has the unsettling name of neurochemical modulation of moral judgment.

They found that in most of the country, housing costs are very close to the cost of construction, but they’re significantly higher in California and some East Coast cities. They note that in these areas, zoning authorities make new construction extremely costly, as much as 50 percent higher in urban areas, which are otherwise favored by immigrants.

As President Harry Truman is credited with saying, “If you want a friend in Washington, buy a dog.”

Because politics is an adversarial game, this lack of understanding leads to demonization of the other side.

Liberals believe conservatives want to take the country back to a time when minorities were treated with gross injustice. Conservatives believe liberals want to pass repressive laws that control every aspect of their lives.

reality, the vast majority of people on both sides of the political divide w...

Psychiatry in London found that dopamine receptors were crowded together more tightly in the brains of people with high P scores compared to those with lower scores. Dense receptor packing led to stronger dopamine signals, which in turn led to the emergence of the distinctive personality features. The connection is also seen when we look at what P stands for: Psychoticism. High P scores are a risk factor for the development of schizophrenia. That doesn’t mean that all liberals are at risk for

One of the unusual characteristics of the human genome is that there is far less variation from person to person compared to other primate species such as chimpanzees or gorillas. This high level of genetic similarity suggests that we are all descendants of a relatively small number of ancestors. In fact, early in our evolutionary history, unknown events killed off a large portion of humans, and the population dwindled to less than 20,000, representing a serious risk of extinction.

They pursue new experiences because they have a low tolerance for boredom. They like to explore new places, ideas, foods, drugs, and sexual opportunities. They are adventurers. Worldwide

the researchers found that the group that made it all the way, indigenous South

Americans, had the highest proportion of long dopamine alleles, 69 percent. Among those who migrated a shorter distance and settled in North America, only 32 percent had the long allele. Indigenous populations in Central America were right in between at 42 percent. On

In fact, stress kills. Stress increases the likelihood of developing heart disease, poor sleep, digestive problems, and immune system impairment. It can also trigger depression, which leads to low

energy, poor motivation, hopelessness, thoughts of death, and simply giving up, all of which militate against survival.

Smarter brains had a greater risk of developing a dopaminergic mental illness compared to ordinary ones.

Instead, scientists believe that it’s caused by a problem with something called the dopamine transporter (Figure 5).

The dopamine transporter is like a vacuum cleaner. Its job is to limit the amount of time dopamine spends stimulating the cells around it. When a dopamine-producing cell fires, it releases its store of dopamine, which then binds to receptors on other brain cells. Then, to bring the interaction to an end, the dopamine transporter sucks the dopamine back into the cell where it came from so the process can start all over again. The transporter is sometimes called a reuptake pump because it pumps the dopamine back into the cell.

Is it possible that minor dysfunction in the dopamine transporter—just a few

risk genes or genes that have only a mild effect—could give people “itchy feet,” so to speak? Might that play a role in the decision to leave one’s home and seek new opportunities in a foreign country?

As of 2005, 52 percent of Silicon Valley start-ups had been founded by immigrant entrepreneurs, a remarkable figure in light of the fact that immigrants make up only 13 percent of the U.S. population.

dopaminergic personality. For example, they asked, “Is success in life determined by forces outside our control?” In Germany, 72 percent said yes. In France it was 57 percent, and in Britain, 41 percent. However, only a little more than a third of U.S. respondents said outside forces were in control, while the majority took a more dopaminergic outlook.

Ask a philosopher what is the essence of humanity, and it wouldn’t be surprising if he said it was free will. The essence of humanity is our ability to move beyond instinct, to go beyond automatic reactions to our environment. It’s the ability to weigh options, to consider higher concepts such as values and principles, and then to make a deliberate choice about how to maximize what we believe is good—whether it’s love, money, or the ennobling of the soul. That’s dopamine.

The academic might say that her essence is the ability to comprehend the world. It’s her ability to rise above the flow of information from the physical senses to understand the meaning of what she perceives. She evaluates, judges, and makes predictions. She understands. That’s dopamine.

The hedonist believes that his deepest self is the part of him that experiences pleasure. Whether it’s wine, women, or song, his purpose in life is to maximize the rewards...

The artist says that the essence of her humanity is her ability to create. It’s her godlike power to call into existence representations of tru...

Finally, the spiritual person might say that transcendence is the root of humanity. It’s the thing that rises above physical reality—the most essential part of who we are is our immortal souls that exist beyond space and time.

It generally means that aspects of her behavior that are outside her conscious control are different. And it’s those aspects that we refer to when we think of “herself”—the essence of who she is.

What else do we neglect when we identify our core being with our dopamine circuits? We neglect emotion, empathy, the joy of being with people we care about. If we ignore our emotions, lose touch with them, they become less sophisticated over time, and may devolve into anger, greed, and resentment.

If we neglect empathy, we lose the ability to make others feel happy. And if we neglect affiliative relationships, we will most likely lose the ability to be happy ourselves—and probably die early. A Harvard study that’s been going on for seventy-four years has found that social isolation (even in the absence of feelings of loneliness) is associated with a 50 to 90 percent higher risk of early death. That’s about the same as smoking, and higher than obesity or lack of exercise. Our brain needs affiliative relationships just to stay alive. We also lose the pleasure of the sensory world around us. Instead of enjoying the beauty of a flower, we imagine only how it would look in a vase on our kitchen table. Instead of smelling the morning air and looking at the sky, we consult the weather app on our smartphone,

In developed countries, people have pretty much lost interest in having children. Raising kids costs a lot of money. According to the U.S. Department of Agriculture it costs $245,000 to raise a child to the age of eighteen. Four years of college tuition plus room and board costs another $160,000, and after college there’s graduate school, or maybe the kids will move back home. Add it all together and you might be able to buy a vacation home or travel overseas every year, not to mention restaurants, the theater, and designer clothes. As one newlywed who planned to have no children succinctly put it, “More money for us.”

Denmark responded to the baby crisis by creating commercials showing a sultry model wearing a black negligee, encouraging viewers to “Do it for Denmark.” Singapore, which has a birthrate of only 0.78, made a deal with Mentos (“The Freshmaker”) to promote “National Night” in which couples were told to let their “patriotism explode.” In South Korea couples earn cash and prizes for having more than one child, and in Russia they get a chance to win a refrigerator.

The next step will be bodysuits that will allow us to experience virtual sex with all our senses, without the inconvenience of reproduction.

A middle-aged man went to see a specialist to have his depression treated. In addition to feeling sad and hopeless, he had an unhealthy obsession with the future. He ruminated over everything that might go wrong, constantly fearful of some unknown catastrophe. His psychic energy was drained by the worry,

and he became emotionally brittle. He blew up at the slightest provocation. He was unable to take the train to work because it was intolerable to be jostled or even touched by other riders. There were nights when his wife woke up at 3 AM to find him in tears. He said, “When you get a flat tire, an ordinary person calls the AAA. I call the suicide hotline.

They researchers concluded that “a human mind is a wandering mind, and a wandering mind is an unhappy mind.”

Cooking, gardening, and playing sports are among many activities that combine intellectual stimulation with physical activity in a way that will satisfy us and make us whole. These activities can be pursued for a lifetime without becoming stale.

Creativity is different because it stirs together H&N with dopamine. It’s like mixing little bit of carbon with iron to make steel. The result is stronger and more durable. That’s what happens to dopaminergic pleasure when you add physical H&N. But

But those of us who prefer a life of happy fulfillment have a different task to accomplish: the task of finding harmony. We have to overcome the seduction of endless dopaminergic stimulation and turn our backs on our never-ending hunger for more. If we are able to intermingle dopamine with H&N, we can achieve that harmony.