How We Decide (25 page)

These new training techniques and tactics had dramatic results. Several years after he published his study, Marshall was sent to fight in the Korean War, and he discovered that 55 percent of infantrymen were now firing their weapons. In Vietnam, the ratio of fire was nearly 90 percent. The army had managed to turn the most personal of moral situations into an impersonal reflex. Soldiers no longer felt a surge of negative emotions when they fired their weapons. They had been turned, wrote Grossman, into "killing machines."

At its core, moral decision-making is about sympathy. We abhor violence because we know violence hurts. We treat others fairly because we know what it feels like to be treated unfairly. We reject suffering because we can imagine what it's like to suffer. Our minds naturally bind us together, so that we can't help but follow the advice of Luke: "And as ye would that men should do to you, do ye also to them likewise."

Feeling sympathetic is not as simple as it might seem. For starters, before you can sympathize with the feelings of other people, you have to figure out what they are feeling. This means you need to develop a theory about what's happening inside their minds so that your emotional brain can imitate the activity of their emotional brains. Sometimes, this act of mind reading is done by interpreting facial expressions. If someone is squinting his eyes and clenching his jaw, you automatically conclude that his amygdala is excited; he must be angry. If he flexes the zygomaticus majors—that's what happens during a smile—then you assume he's happy. Of course, you don't always have access to a communicative set of facial expressions. When you talk on the phone or write an e-mail or think about someone far away, you are forced to mind read by simulation, by imagining what you would feel in the same situation.

Regardless of how exactly one generates theories of other people's minds, it's clear that these theories profoundly affect moral decisions. Look, for example, at the ultimatum game, a staple of experimental economics. The rules of the game are simple, if a little bit unfair: an experimenter pairs two people together, and hands one of them ten dollars. This person (the proposer) gets to decide how the ten dollars is divided. The second person (the responder) can either accept the offer, which allows both players to pocket their respective shares, or reject the offer, in which case both players walk away empty-handed.

When economists first started playing this game in the early 1980s, they assumed that this elementary exchange would always generate the same outcome. The proposer would offer the responder about a dollar—a minimal amount—and the responder would accept it. After all, a rejection leaves both players worse off, and one dollar is better than nothing, so this arrangement would clearly demonstrate our innate selfishness and rationality.

However, the researchers soon realized that their predictions were all wrong. Instead of swallowing their pride and pocketing a small profit, responders typically rejected any offer they perceived as unfair. Furthermore, proposers anticipated this angry rejection and typically tendered an offer of around five dollars. This was such a stunning result that nobody really believed it.

But when other scientists repeated the experiment, the same thing happened. People play this game the same way all over the world, and studies have observed similar patterns of irrationality in Japan, Russia, Germany, France, and Indonesia. No matter where the game was played, people almost always made fair offers. As the economist Robert Frank notes, "Seen through the lens of modern self-interest theory, such behavior is the human equivalent of planets traveling in square orbits."

Why do proposers engage in such generosity? The answer returns us to the act of sympathy and the unique brain circuits that determine moral decisions. Adam Smith, the eighteenth-century philosopher, was there first. Although Smith is best known for his economic treatise
The Wealth of Nations,
he was most proud of
The Theory of Moral Sentiments,
his sprawling investigation into the psychology of morality. Like his friend David Hume, Smith was convinced that our moral decisions were shaped by our emotional instincts. People were good for essentially irrational reasons.

According to Smith, the source of these moral emotions was the imagination, which people used to mirror the minds of others. (The reflective mirror, which had recently become a popular household item in Smith's time, is an important metaphor in his writing on morality.) "As we have no immediate experience of what other men feel," Smith wrote, "we can form no idea of the manner in which they are affected, but by conceiving what we ourselves should feel in the like situation." This mirroring process leads to an instinctive sympathy for one's fellow man—Smith called it "fellow-feeling"—that forms the basis for moral decisions.

Smith was right. The reason a proposer makes a fair offer in the ultimatum game is that he is able to imagine how the responder will feel about an unfair offer. (When people play the game with computers, they are never generous.) The responder knows that a low-ball proposal will make the other person angry, which will lead him to reject the offer, which will leave everybody with nothing. So the proposer suppresses his greed and equitably splits the ten dollars. That ability to sympathize with the feelings of others leads to fairness.

The sympathetic instinct is also one of the central motivations behind altruism, which is demonstrated when people engage in selfless acts such as donating to charity and helping out perfect strangers. In a recent experiment published in
Nature Neuroscience
, scientists at Duke University imaged the brains of people as they watched a computer play a simple video game. Because the subjects were told that the computer was playing the game for a specific purpose—it wanted to earn money—their brains automatically treated the computer like an "intentional agent," complete with goals and feelings. (Human minds are so eager to detect other minds that they often imbue inanimate objects, like computers and stuffed animals, with internal mental states.) Once that happened, the scientists were able to detect activity in the superior temporal sulcus and other specialized areas that help each of us theorize and sympathize with the emotions of other people. Even though the subjects knew they were watching a computer, they couldn't help but imagine what the computer was feeling.

Now comes the interesting part: the scientists noticed that there was a lot of individual variation during the experiment. Some people had very active sympathetic brains, while others seemed rather uninterested in thinking about the feelings of someone else. The scientists then conducted a survey of altruistic behavior, asking people how likely they would be to "help a stranger carry a heavy object" or "let a friend borrow a car." That's when the correlation became clear: people who showed more brain activity in their sympathetic regions were also much more likely to exhibit altruistic behavior. Because they intensely imagined the feelings of other people, they wanted to make other people feel better, even if it came at personal expense.

But here's the lovely secret of altruism:
it feels good.
The brain is designed so that acts of charity are pleasurable; being nice to others makes us feel nice. In a recent brain-imaging experiment, a few dozen people were each given $128 of real money and allowed to choose between keeping the money and donating it to charity. When they chose to give away the money, the reward centers of their brains became active and they experienced the delightful glow of unselfishness. In fact, several subjects showed more reward-related brain activity during acts of altruism than they did when they actually received cash rewards. From the perspective of the brain, it literally was better to give than to receive.

ONE OF THE
ways neuroscientists learn about the brain is by studying what happens when something goes wrong with it. For example, scientists learned about the importance of our moral emotions by studying psychopaths; they learned about the crucial role of dopamine by studying people with Parkinson's; and brain tumors in the frontal lobes have helped to illuminate the substrate of rationality. This might seem callous—tragedy is turned into an investigative tool—but it's also extremely effective. The broken mind helps us understand how the normal mind works.

When it comes to the sympathetic circuits in the human brain, scientists have learned a tremendous amount by studying people with autism. When Dr. Leo Kanner first diagnosed a group of eleven children with autism, in 1943, he described the syndrome as one of "extreme aloneness." (Aut is Greek for "self," and
autism
translates to "the state of being unto one's self.") The syndrome afflicts one in every 160 individuals and leaves them emotionally isolated, incapable of engaging in many of the social interactions most people take for granted. As the Cambridge psychologist Simon Baron-Cohen puts it, people with autism are "mind-blind." They have tremendous difficulty interpreting the emotions and mental states of others.
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Scientists have long suspected that autism is a disease of brain development. For some still mysterious reason, the cortex doesn't wire itself correctly during the first year of life. It now appears that one of the brain areas compromised in people with autism is a small cluster of cells known as mirror neurons. The name of the cell type is literal: these neurons mirror the movements of other people. If you see someone else smile, then your mirror neurons will light up as if you were smiling. The same thing happens whenever you see someone scowl, grimace, or cry. These cells reflect, on the inside, the expressions of everybody else. As Giacomo Rizzolatti, one of the scientists who discovered mirror neurons, says, "They [mirror neurons] allow us to grasp the minds of others not through conceptual reasoning but through direct simulation; by feeling, not by thinking."

This is what people with autism have to struggle to do. When scientists at UCLA imaged the brains of autistic people as they looked at photographs of faces in different emotional states, the scientists discovered that the autistic brain, unlike the normal brain, showed no activity in its mirror-neuron area. As a result, the autistic subjects had difficulty interpreting the feelings on display. They saw the angry face as nothing but a set of flexed facial muscles. A happy face was simply a different set of muscles. But neither expression was correlated with a specific emotional state. In other words, they never developed a theory about what was happening inside other people's minds.

A brain-imaging study done by scientists at Yale sheds further light on the anatomical source of autism. The study examined the parts of the brain that were activated when a person looked at a face and when he or she looked at a static object, like a kitchen chair. Normally, the brain reacts very differently to these stimuli. Whenever you see a human face, you use a highly specialized brain region called the fusiform face area (FFA) that is solely devoted to helping you recognize other people. In contrast, when you look at a chair, the brain relies on the inferior temporal gyrus, an area activated by any sort of complex visual scene. However, in the study, people with autism never turned on the fusiform face area. They looked at human faces with the part of the brain that normally recognizes objects. A person was just another thing. A face generated no more emotion than a chair.

These two brain deficits—a silent mirror-neuron circuit and an inactive fusiform face area—help to explain the social difficulties of people with autism. Their "extreme aloneness" is a direct result of not being able to interpret and internalize the emotions of other people. Because of this, they often make decisions that, in the words of one autism researcher, "are so rational they can be hard to understand."

For instance, when people with autism play the ultimatum game, they act just like the hypothetical agents in an economics textbook. They try to apply a rational calculus to the irrational world of human interaction. On average, they make offers that are 80 percent lower than those of normal subjects, with many offering less than a nickel. This greedy strategy ends up being ineffective, since the angry responders tend to reject such unfair offers. But the proposers with autism are unable to anticipate these feelings. Consider this quote from an upset autistic adult whose offer of ten cents in a ten-dollar ultimatum game was spurned: "I did not earn any money because all the other players are
stupid!
How can you reject a positive amount of money and prefer to get zero? They just did not understand the game! You should have stopped the experiment and explained it to them..."

Autism is a chronic condition, a permanent form of mind blindness. But it's possible to induce a temporary state of mind blindness, in which the brain areas that normally help a person sympathize with others are turned off. A simple variation on the ultimatum game, known as the dictator game, makes this clear. Our sense of "fellow-feeling" is natural, but it's also very fragile. Unlike the ultimatum game, in which the responder can decide whether or not to accept the monetary offer, in the dictator game, the proposer simply dictates how much the responder receives. What's surprising is that these tyrants are still rather generous and give away about one-third of the total amount of money. Even when people have absolute power, they remain constrained by their sympathetic instincts.

However, it takes only one minor alteration for this benevolence to disappear. When the dictator cannot see the responder—the two players are located in separate rooms—the dictator lapses into unfettered greed. Instead of giving away a significant share of the profits, the despots start offering mere pennies and pocketing the rest. Once people become socially isolated, they stop simulating the feelings of other people. Their moral intuitions are never turned on. As a result, the inner Machiavelli takes over, and the sense of sympathy is squashed by selfishness. The UC Berkeley psychologist Dacher Keltner has found that in many social situations, people with power act just like patients with damage to the emotional brain. "The experience of power might be thought of as having someone open up your skull and take out that part of your brain so critical to empathy and socially appropriate behavior," he says. "You become very impulsive and insensitive, which is a bad combination."