The Leap_ The Science of Trust and Why It Matters.

Ulrich Boser.

To those who have trusted me.

Author's Note.

Please connect with me on Facebook or Twitter or email me at I will also keep a running log of errors, clarifications, and questions on my website, ulrichboser.com.

While this is an original work of nonfiction, I have relied on many outside sources for quotes, data, and other factual information, which I have cited in the endnotes. In some instances, I have used text that first appeared in other publications. That is also indicated in the endnotes. If a quote is in italics, it means that the words may not be exact. In some instances, I may have altered quotes for grammar and clarity.

To ensure accuracy, I shared some portions of the book with experts or sources. I also hired a fact-checker to help vet the accuracy of the material. All errors of logic, fact, or writing are, no doubt, mine.

Introduction.

Most of the members of the Old Christians rugby team slept in. It was the morning of October 13, 1972, and some bad weather had grounded the rugby team's charter flight to Santiago, Chile. Some of the young men had been out dancing the night before, and when they finally straggled into the airport later that day, the rugby players taunted the airplane pilots: Were the pilots too scared to cross the mountains?

The Fairchild finally rose into the sky in the early afternoon while some of the team members played card games.1 A few tossed a rugby football down the aisle, yelling "Think fast!"2 When a spot of turbulence shook the plane, they whooped like bullfighters.

As the small plane flew over a narrow, mountainous pa.s.s, it slipped into a dense bank of clouds. Strong winds started to rattle the aircraft. At one point, the turboprop dropped a few hundred feet, and when the clouds finally drew apart again, a rocky cliff appeared just beyond one of the wings.

"Is it normal to fly so close to the mountains?" one of the pa.s.sengers asked.3 "I don't think so," his friend answered.

Moments later, there was a long shudder. A rocky crag sc.r.a.ped the bottom of the fuselage, and the tail section crashed away. The wings broke off. The plane soared for a moment or two before skidding down the slope of a mountain, and among the lifeless bodies and splintered luggage, there were more than two dozen survivors who spent the night huddled in the broken plane.4 The cold was severe, something profound, and the group didn't have any warm coats. The team had packed for a trip to the ocean, not the mountains. Even worse, there was no food. The men had just a few candies and a bit of dried fruit, and within days the survivors began to feed on the frozen corpses scattered around the crash site. Sometimes the meat was cooked. Usually it was eaten raw. Then, roughly two weeks after the crash, a blanket of wet snow killed another half dozen men. "It is hard to describe the depths of the despair that fell upon us in the wake of the avalanche," writes Nando Parrado in his memoir, Miracle in the Andes. "Now we saw that we would never be safe in this place."

Among the men, the urge to be selfish, to take a little more food or clothing or water for themselves, was strong. Everyone was deeply hungry. Everyone was exquisitely cold. Yet the survivors figured out a way to come together, as doc.u.mentaries like Stranded have suggested. They created a strict system for sleeping positions, since spots farther away from the door were warmer and more comfortable.5 Everyone received the exact same ration of cigarettes.6 The men continued to care for the wounded, ma.s.saging the feet of the injured to save their toes from frostbite.7 "When one suffered, everyone did. If someone did something wrong, everyone reacted," Fito Strauch told the producers of Stranded.8 "There was no room for anyone to do anything that was against the general interest. It was like a nineteen-bodied organism."

Nearly two months after the crash, two of the survivors managed to trek out of the mountains, and the Chilean Air Force eventually saved the rest of the group. In the years since the dramatic rescue, the story of the crash has become the subject of movies, books, and doc.u.mentaries, and the attraction is clear: People want to know how the group made it out alive. There are some obvious reasons for their survival. Many of the men were athletes, strong and well trained. The survivors were also young and determined. They wanted to return home, to see their families, to see their friends. Religion also played a role, and many of the survivors saw the eating of the dead bodies as something almost holy.

Perhaps most remarkable, though, is that the men built up a sense of faith in each other. Or, as Nando Parrado writes in Miracle in the Andes, "None of us were saints. We survived not because we were perfect, but because the acc.u.mulated weight of our concern for each other far outweighed our natural self-interest."

Today, many of the survivors are in their sixties. They're doctors, lawyers, and architects. They own houses. They have grandchildren. For three decades now, the group has gotten together every December to celebrate their survival. In those moments, it seems, the men renew the community that they once created, a community built on the promise that they made to each other while they were starving in the Andes: If one of them died, the others could eat his body so that they could live.

According to popular wisdom, what happened in the Andes should not have happened. No one stuck in subzero temperatures is supposed to give up his blanket. No one stranded in a crashed airplane is supposed to share his sweater with someone else, and today, almost 60 percent of Americans argue that you "can't be too careful in dealing with people."9 Just about one in ten Americans thinks that their business leaders are honest.10 In my own research, I've found that in some states almost no one says that they fully trust other people.

The conventional wisdom isn't fully accurate, though, and our sense of faith can be restored. We can improve our social bonds, and the reason is simple, as researcher Pamela Paxton once pointed out.11 Our deeply negative view of others doesn't match up with the science, and it turns out that we evolved to work with others. We have a deep-seated urge to be fair and warmhearted.12 The headlines might suggest a nation filled with greedy jerks and selfish egoists, with scam artists and Ponzi schemes, but our raw impulsive response is often to place our faith in others and return that faith once it's given.13 What's more, trust turns out to be a type of "social glue," and our faith in others builds social capital.14 It creates social networks. It's what keeps every group together, whether it's a team of football players or a nation of hundreds of millions. Or think back to the men in the Andes. If they didn't have some sort of faith in each other, they could never have lived for seventy-two days in one of the world's most desolate places.

My goal with this book is to better understand our faith in others and provide some ways to improve social trust. Or, to paraphrase Nando Parrado, I want to show how we can make our concern for each other outweigh our natural self-interest. Before we go any further, though, we have to acknowledge that society has changed, and we will not return to the social cohesion of the 1950s anytime soon. Some form of individualism is here to stay. But, at the same time, we all need to be part of something bigger than ourselves. We're all motivated by more than our own self-interest, and greater levels of social cohesion can dramatically improve the nation's well-being. It can boost health outcomes-and jump-start the economy. As we'll see, social trust can even drive down the nation's murder rate.

I decided to write this book after working on an initiative to improve faith in government for the Center for American Progress, a nonpartisan think tank where I'm a fellow. I became fascinated with the new research on why we trust others. I soon began visiting psychology research labs. Obscure economic studies became my bedtime reading. Neuroscientist Brooks King-Casas once scanned my brain in an fMRI to help me better understand the neuroscience of cooperation.

In other words, this book builds upon the work of many others. I'm indebted in particular to the research and writings of Yochai Benkler, Bruce Schneier, and Robert Putnam.15 An essay by Jeremy Adam Smith and Pamela Paxton t.i.tled "America's Trust Fall" was an early and important inspiration.16 But I might be most grateful for the help of Paul Zak, a neuroeconomist at Claremont Graduate University. Zak and I went skydiving together to see if the experience would increase my levels of oxytocin, the so-called trust hormone, and I'm deeply appreciative of any source that is willing to roar through the heavens with me at 120 miles per hour.

In this book, I examine the degree to which we broadly trust others, or what researchers call social trust. I rely on a well-cited definition of our faith in others, which I've paraphrased here: Trust is when you a.s.sume vulnerability with an optimistic expectation of someone else.17 This sort of trust comes in different forms. There's what experts call calculation-based trust, where we place our faith in someone by estimating the chance that they might betray us.18 This sort of trust is logical, a type of risk. But it often turns into what's called relational trust, which is more emotional, less rational, and when it comes to relational trust, we often want some sort of connection. The other thing to keep in mind is that the study of trust remains young, and like many things that are young, there is uncertainty. And so while the ideas contained in this book are rooted in the latest thinking, not everything is conclusive.

With regard to the narrative, the first part of the book is devoted to understanding the basics of trust. I'll discuss oxytocin and describe how with a single dose of this chemical, people become more trusting. I'll also look at how and why we place our faith in strangers and discuss the role that our everyday experiences play in our faith in others. Throughout the book, I'll focus on some of the key drivers of trust, from social networks to a sense of empowerment. I'll also look at the crucial roles of culture and government and social capital. I also hope to underscore the role of trustworthiness, because without dependability, without honesty and transparency, trust can't exist.

In the second half of the book, we'll look at some ways that we can use our knowledge of trust to improve the world we live in. I'll look at how we can increase trust in teams and how technology is changing our sense of faith in others, and we'll find out, for instance, how a website helped a young military cadet and a middle-aged, gay nudist become friends. I'll also talk about some of the ways we might boost trust in government, which can go a long way to support our faith in others. Americans currently have a better opinion of c.o.c.kroaches than they do of Congress, and we will look at why that matters-and what we can do about it.19 As part of my research, I traveled to Rwanda to better understand how the African nation is rebuilding a sense of trust. In the back of the book, I've included a policy tool kit that outlines what our government can do to restore our faith in others. Ultimately, I hope to convince you that we can recover our feeling of connection, our sense of community, and through the power of our trusting ways, through the strength of our social nature, we can build a more meaningful society.

But for now, let's start with a different leap of faith. Let's start with a game known as Split or Steal.

PART I.

Why We Trust.

Chapter 1.

The Social Instinct.

Why We Trust.

THE British TV program Golden b.a.l.l.s was a standard afternoon game show. There was a sappy host, a glittery stage, and lots of flas.h.i.+ng lights.1 The show had a strong run with some two million viewers in the late 2000s, and the contestants came from a variety of backgrounds. One worked as an accounts manager. Another as a medical secretary. Some were young men. Others were middle-aged women. All of them dreamed of taking home the show's jackpot, which could be as much as $175,000.

The show itself was a mash-up of Deal or No Deal and Survivor. In the last round, the two most successful contestants would sit in the middle of the brightly lit stage and compete face-to-face in a game called Split or Steal. The basic premise of Split or Steal was this: If the players worked together, they would share the jackpot. If one player cooperated and the other player betrayed, the double-crosser would keep the jackpot for himself. The twist was that if both players double-crossed each other, then neither of them would get anything. Or, as the show's host would say to the players in a deep voice: You go home with nothing.

To get a flavor of the game, imagine for a moment that you're playing Split or Steal for a jackpot of $100,000.2 The overhead lights are hot and bright. Your hands shake with anxiety. Everything seems loud, almost neon, and so you take some time to mull your options.

If you work with your partner, if you cooperate with him or her, you might take home $50,000. That's a lot of money. More than enough for a new car.

And yet you have no idea if your partner will work with you. After all, your partner is also probably dreaming of a better car, and there's nothing holding your partner back from double-crossing you. There are no laws against being nasty to someone else on a television game show. Put simply, there doesn't seem to be any good reason to trust your partner.

What's more, if you betray your partner and manage to double-cross him or her, you will take home $100,000, and with that sort of money, you could make a down payment on an oceanside condo in Florida.

In a way, the research questions posed by Split or Steal are obvious: In a real-world test of trust and cooperation, do individuals show any faith in strangers? If hundreds of thousands of dollars are on the line, do most people do the right thing?

A few years ago, two economists, Donja Darai and Silvia Gratz, tried to answer these questions, and what they found was surprising. It turned out that most of the people who played Split or Steal trusted the other. Despite the fact that that the logical thing to do in the game was to betray the other person, more than 50 percent of the contestants showed a sense of faith in their partner.

What's more, one of the best predictors of whether or not the players worked together was the degree to which they had some sort of meaningful interaction. If the two people talked about cooperating, if they made a clear and concrete promise to help each other, they were far more likely to trust. In fact, a conversation between the two players remained a powerful predictor of cooperation even after considering factors like gender, where the individuals grew up, and even their previous history of betraying others. The only thing that made the bond between the players stronger? If they shook hands or hugged each other. In other words, the only factor that made a verbal connection stronger was underscoring it with a physical connection.

If you read a lot of blogs, if you watch a lot of YouTube, if you pay attention to game show hosts, you might believe that you're never supposed to put your faith in a stranger. After all, people are not supposed to be trustworthy. This notion is widespread, and social trust is the lowest it has been in decades. Survey after survey shows weak levels of social cohesion, and selfishness has become central to all sorts of ideas and beliefs, from psychology to business. Or take the Split or Steal study. When I reached out to Donja Darai in her offices at the University of Zurich, she told me that many experts believe "that people are only interested in maximizing their own profit." But, she added, "That's clearly not the whole story."

In fact, that's far from the whole story, and it turns out that we innately care about others. We're wired to live in groups, and for many of us, trust and trustworthiness are unconscious, automatic, a part of our habitual brains. And in most experiments that measure trust and trustworthiness, individuals will invest half of their cash in a stranger, and many people are reliable and give some money back.3 In another series of studies involving American college students, neuroeconomist Paul Zak has found that as many as 90 percent of subjects trusted people that they didn't know and around 95 percent of those subjects were trustworthy.4 The results of these sorts of trust experiments suggest that our faith in others is a part of "human nature," as economist Kay-Yut Chen argues. The research also indicates that our tendency to trust-and be trustworthy-will s.h.i.+ft depending on the situation, and if people play a Split or Stealtype game against a real person, they trust more than if they play against a computer. But perhaps the most striking conclusion is regarding the role of human bonds, and our social ties, our notions of togetherness, the network of relations.h.i.+ps that make up our daily lives: They all support our sense of trust. We see this in the Split or Steal study, where people who shared social connections were more likely to trust each other. We see this in other trust experiments, too. When psychologists recently played a version of the Split or Steal game with adults who had been brought up in single-child households in China, they found those people to be less trusting than the people who grew up with siblings. China's one-child policy "has given rise to a land of 'little emperors' whose parents dote on them exclusively," the authors concluded.5 Our deeply cooperative nature might offer the best way to restore our sense of social trust, as Smith and Paxton suggest. But before we examine that idea, we should gain a better sense of just how social we are as a species, and consider for a moment what happens to people who are placed in solitary confinement. For many of us, a few months by oneself in a room might not seem like a terrible punishment. Sure, you'll miss your friends and family. You'll be bored and irritated and maybe a bit lonely. But if you have something to read and can write some letters, how bad could it be?

The answer is: very bad. Solitary confinement can cause terrible psychological harm; it causes a type of disorder that attacks the mind from the inside. Take, for instance, the work of psychologist Craig Haney.6 For decades, he has been studying inmates who've been placed in isolation wards. Haney's accounts of what happens to such people are raw and gruesome. During a stint in solitary confinement, one man became so distraught that he st.i.tched up his lips with a bit of thread. Another man gnawed off one of his fingers, sliced open his foot, and managed to detach his t.e.s.t.i.c.l.es. Still another man began eating his television. The guards had to pump that inmate's stomach, and after the authorities returned the inmate to his cell, he went right back to devouring his electronics.

People who come out of solitary confinement often recover. Once they engage with others again, they feel better. Their sense of self returns. This all seems to have a straightforward cause: When we have no one to bond with, when we have no one to trust, our brains can self-destruct. It's not exactly clear why this happens. But what's certain is that we have a profound urge to connect to others. We have a constant need to socialize. Or as psychologist Michael Gazzaniga once argued, "We are a bunch of party animals."7 This instinct to form groups has a long evolutionary history. For our distant Paleolithic cousins, other people meant safety and protection, and research suggests that primates traveling in smaller clans have less security against predators.8 In fact, the pain of being alone seems to have evolved to s.h.i.+eld us from the hazards of actually being alone.9 What's more, our neural circuits evolved to be groupish. The process of navigating our social ties is baked into our brains.10 Or as social physiologist Matthew Lieberman argues, "This is what our brains were wired for: reaching out to and interacting with others." So, for example, most of us struggle to multiply 78 times 38 in our heads, even though, as math problems go, it's not very difficult.11 In contrast, if I were to show you a picture of your kindergarten cla.s.s, I'd bet that you'd be able to recognize the faces of everyone in the cla.s.s. I'd also wager that you'd be able to tell me who threw sand, who picked his nose, and who rubbed your back after you wet your pants.

To put it differently, we have a lot of the highly networked bee in our nature, and rather than viewing ourselves as the rational ape, we'd be better off thinking of ourselves, as psychologist Jonathan Haidt recommends, as "ninety percent chimp and ten percent bee."12 Because, like bees, we can become part of something bigger, something hive-ish. Or, as Haidt writes, "We are selfish primates who long to be a part of something larger and n.o.bler than ourselves."

To paraphrase Haidt, then, we are the gregarious ape, the super-smart lemming, and for many of us, trust is an emotive urge. Psychologist Roderick Kramer describes this as "presumptive trust," and when the investor sends money in a game like Split or Steal, the person is essentially saying: Be part of my group.13 Let's work together. Let's be friends. And even the smallest signal of affability can build up a sense of faith, and Kramer notes that just a minor social signal like a handshake will make people more trusting. Psychologist Robert Kurzban once had players give each other a bit of eye contact in a Split or Steallike experiment, and that alone was enough to boost the levels of cooperation.14 Think about that for a second. Just some eye contact can create a feeling of bonding. The idea that our social ways are behind our trusting ways dates back hundreds of years. But recent research has made it clear that we have a deep need to connect to others. For humans, trust is a type of social instinct.

During World War II, the U.S. Army hoped to answer the question: Why do men fight?15 The question should have been easy to answer-we've been fighting wars for thousands of years. But the question of bravery is harder than it seems, and at the start of World War II, the army didn't have a reliable approach for inspiring its new recruits. Generals seemed to think that bravery was a mix of self-interest and patriotism, and when studies suggested that morale was low, the army often tried to appeal to the soldiers' inner egos. They talked about pride and changed pay structures and created a point system so that soldiers could figure out when they would be discharged. General George C. Marshall also brought in film director Frank Capra to make a movie that would explain the causes of the war. Almost every incoming soldier saw the resulting film, Why We Fight, which argued that World War II was about liberty and American security. Put simply, the men were supposed to be fighting the n.a.z.is to save themselves and their way of life.

But the army also knew that might not be enough, so in the 1940s, it tapped sociologist Samuel Stouffer to study the issue of bravery. Stouffer launched a ma.s.sive research project, surveying some 500,000 enlisted men, and it turned out that the men didn't fight because of patriotism or money or fear of n.a.z.i domination. For them, the war wasn't about saving American liberty. Instead, the men fought because they believed in each other, and when Stouffer asked soldiers what kept them going, their most common response was finis.h.i.+ng the job so that they could return to the States. But the second most common response-and the "primary combat motivation"-was a sense of connection to others.16 Stouffer's finding might seem odd at first glance. The men were terrified for their lives. They faced mortar rounds and sniper fire, dive-bombings and artillery attacks, Panzers and bombers. Why would their buddies make a difference? Well, trust can provide a type of well-being, a feeling of emotional support, and when you are jumping out of a foxhole, when you expect a bullet in the chest, when a German tank might kill you at any moment, faith in others can seem like the only thing that matters. A few years ago, Leonard Wong, of the United States Army War College, re-created Stouffer's study, and the findings held up. As one infantryman told Wong, "You have got to trust [other soldiers] more than your mother, your father, or girlfriend, or your wife, or anybody. It becomes almost like your guardian angel."17 For the most part, we don't see others as the solution to our problems-or as central to our future well-being. But our social bonds sustain us, and people with deeper social ties live longer and are less likely to die of a heart attack or cancer.18 They're also less likely to be anxious or depressed. They're even less likely to catch a cold. Studies also suggest that people with deeper social connections are more effective at work, and individuals with warmer relations.h.i.+ps can earn almost twice as much money as their less connected counterparts.

Why does this happen? Why would working with others give us any sort of support at all? There isn't a simple explanation. Part of the reason, it seems, is that when we're connected with others, we gain more information, which helps us solve problems more easily. By bonding with others, we also feel better about our group. And then there are our brains, and it turns out that when we connect with others, our opiates can kick in and give us a bit of joy. In a way, we know this already, as neuroscientist Patricia Churchland points out, and we have feel-good interactions with other people all the time. At work, at home, in school, we chatter with someone for a few moments and feel a little surge of happiness. Churchland admits that this isn't a real "high," but it does seem that for our brains, bonding can sometimes be its own reward.

It's easy to get carried away here, and we're not built to place our faith in everyone, as we'll see later in this book. But the bottom line is that social trust is a type of binding tissue, the so-called lubricant of society, and in the end, our social ties are what support us. I wanted to learn more about this idea and its connection to trust, and so I went to Yerkes National Primate Research Center. The field station sits a few dozen miles north of Atlanta, down a long road, nestled within a glade of pine trees. When I visited on a summer afternoon, the high-pitched screams of the primates pierced the air, as if the sounds of a far-off African jungle had been piped into the Georgia landscape. Inside the gates, some chimpanzees tussled on a football fieldsized playground. Further inside, a few rhesus monkeys swung on a large climbing structure with ladders and tires and ropes.

I went to Yerkes to talk with primatologist Frans de Waal.19 On the day that I arrived, de Waal wore a T-s.h.i.+rt and shorts. His white hair was cut short. Together we climbed a tall tower, which overlooked the jungle gymlike chimpanzee enclosure, and de Waal pointed out a young female chimp who was teasing an adult with a long branch.

"She's testing out her boundaries," de Waal explained. For de Waal, this wasn't a big deal. Squabbles are inevitable. More important was that after a quarrel occurs, chimps will typically comfort the victims of the fight, hugging and touching them. "We call it consolation behavior," de Waal told me. "We see it every day."

Consolation runs on empathy, according to de Waal, and researchers like de Waal define empathy as the ability to feel someone else's feelings. As an idea, empathy covers more than that, and for de Waal, the notion of empathy also includes another talent called perspective taking, or the ability to think what others are thinking. Empathy runs deep within our mammalian DNA, and many animals-mice, rats, dogs-appear to feel the feelings of others.

In humans, though, empathy seems particularly strong. In his office, de Waal showed me a video of contagious yawning among chimpanzees, and I soon found myself yawning. What's more, our empathy is a type of deep-seated social compa.s.s, and de Waal pointed out that chimps are more likely to contagiously yawn in response to someone within their group than someone outside of it.

"So I would be more likely to contagiously yawn for my wife than for a stranger?" I asked.

De Waal nodded. "This is all related to very basic levels of empathy."

But there's another lesson, just as important-it turns out that we need empathy to work in a group, according to de Waal. Without some sense of the feelings of our partners, without some sort of connection to them, it's nearly impossible to cooperate with them, and when we walk for a moment in someone else's loafers or moccasins or clogs, we can better understand what he or she wants. Or to paraphrase de Waal: We need to know the thoughts of a colleague in order to figure out if he or she needs our help. Within a small group, people need to know what their allies are thinking so that they can collaborate with them more closely.

What's more, empathy makes us more trustworthy. Or look at it like this: Trust often relies on the principle of reciprocity. I do something for you, you do something for me, and we reciprocate all the time. But self-interested reciprocity is not enough. It's too shortsighted, and if you're logical and playing something like Split or Steal, you shouldn't trust the other person. It's too likely that he'll cheat you.

Our emotions help solve this problem, as economist Robert Frank suggests.20 We are motivated by more than the a.s.surance that we will receive something in return-we also don't want to feel the hurt of others. In other words, empathy and its prosocial cousins-sympathy, compa.s.sion, affection-make us act in a more trustworthy way. They serve as a type of "impulse-control device," as Frank argues.

In this sense, it's empathy-along with the rest of our social emotions-that ultimately makes society possible. Philosopher Peter Singer has argued that our earliest ancestors probably felt a sense of empathy only for the people in their clan.21 But over time, Singer argues, our circle of morality grew larger, and today we feel even for other species because once we start to empathize with others, it's hard to stop. "Were we incapable of empathy-of putting ourselves in the position of others and seeing that their suffering is like our own-then ethical reasoning would lead nowhere," Singer writes.22 "If emotion without reason is blind, then reason without emotion is impotent."

We don't want to have empathy for everyone. No one does, and computer simulations show that trust and cooperation move in cycles.23 Empathy might start a partners.h.i.+p-and everyone might become more reliable and honest-but sooner or later, someone will decide to look out for his own interests. A person will steal or cheat or just take advantage of the system. And if you're stuck in a group of untrustworthy people, it pays to distrust. When you're surrounded by selfish, unempathetic rogues, the best approach is to be a selfish, unempathetic rogue. But the cooperative instinct always seems to appear again, according to research by mathematical biologist Martin Nowak, and, in the end, our trusting ways run so deep that we even have brain circuits devoted to working with others.24 There's a lot that scientists don't know about these circuits. But remarkably, the story of these circuits starts in many ways with a hamster-like animal known as the prairie vole.25 Researchers sometimes refer to prairie voles as common pests, and what's ultimately interesting about the animals is that they're deeply committed to each other. Female voles spend more than a third of their time in contact with their partners. Males will give up more than half of their day caring for their offspring. Or, as science writer Steven Johnson argues in his wonderful book Mind Wide Open, voles are "one of the natural world's great romantics."26 Some years ago, a few biologists at the University of Illinois wanted to better understand why this happened, and so they began studying the voles, keeping the rodents in cages, giving them rabbit food, and running experiments on them with various hormones. The findings were notable, especially when it came to a peptide known as oxytocin. At the time, researchers didn't know all that much about the chemical, and most experts thought that oxytocin was a simple pregnancy hormone that promoted stronger contractions during the birthing process.

Neuroscientist Sue Carter was one of the pioneers of the vole research, and she told me that she had long known that oxytocin was an important chemical. In fact, doctors had given Carter oxytocin when she was giving birth to her son. But it took study after study to show just how central the hormone was to creating a sense of connection among the voles. "We spent ten years just proving that this was a true social bond and that oxytocin played a role in it," Carter told me.

Others soon began building on Carter's work, and by the late 1990s, researchers had gone a long way to understanding the bonding mechanisms of the small animals. They knew that the oxytocin circuit was a primordial one, dating back some 100 million years. They also knew that many other chemicals and biological systems played a key role. Male voles, for instance, stopped caring for their children only if both vasopressin and oxytocin receptors were shut down, as Carter told me.

But a bigger issue remained: Were humans any different? And what would it mean if they were?

Those questions buzzed across Paul Zak's mind the first time that he heard about oxytocin. He was sitting in a shuttle bus at the time, heading to a conference south of Reno, Nevada. As the woodland of pines and junipers roared past his window, Zak began talking with the woman sitting next to him.27 She turned out to be an anthropologist who studied the science of love, and when she heard that Zak studied trust and social capital, she asked, "Have you ever thought about studying oxytocin?"

Back then, Zak didn't know all that much about oxytocin. This was long before Zak tickled my chest to show me that the sternum has lots of oxytocin receptors. This was long before he flew to Papua New Guinea to see if oxytocin spiked before and after men performed a tribal dance. At the time, Zak's area of expertise was econometrics, not neuroscience, and he had recently shown that economic growth jumps by almost 1 percent for every 15 percent increase in trust.28 When Zak got back to his hotel later that day, he logged into a medical database and began reading the research on prairie voles. As he glanced through the studies, he couldn't get away from the nagging sense that the effect of oxytocin bore a significant resemblance to trust.29 They both involve a quieting feeling, a sense of safety and comfort. In his book The Moral Molecule, Zak recalls thinking, "What if bonding in voles and trust in humans were actually based on the same chemistry? What if oxytocin was, in fact, the chemical signature for that elusive bonding force [Adam] Smith had called mutual sympathy?"

It took time and research and practice, but eventually Zak started running his own oxytocin experiments. One of his very first studies was straightforward: He had undergraduates play a Split or Stealtype game and afterward took samples of their blood. The results showed an unambiguous relations.h.i.+p between the level of faith among the players and the amount of oxytocin in their blood.30 But that experiment alone didn't prove anything, as Zak notes. It didn't show that oxytocin actually caused the players to trust each other. It didn't mean that we were like prairie voles, who have a clear, hormonally based system for bonding with others.

Zak wanted to prove the connection conclusively. But at the time, the FDA didn't make it easy for researchers to use oxytocin inhalers. Zak didn't want to wait, though. A self-proclaimed recovering jock, Zak is a doer. He has a warm, brawny personality, the sort of guy who even in his fifties will take off his s.h.i.+rt during a lecture and rub testosterone on his bare shoulders just to make a point. (It helps that Zak has the muscular build of a college basketball player.) Or consider what happened when I first reached out to Zak. I came across the neuroeconomist's research in a wonderful profile of Zak that Adam Penenberg had written for Fast Company, and I wanted to find out more about oxytocin's connection to trust.31 So I emailed Zak and told him that I was working on a book on our faith in others. He wrote back and said simply: "I'm your guy."

So instead of slowly wading through the lengthy FDA-approval process, Zak began working with a group of European researchers. One of the psychologists, Markus Heinrichs, had also run some groundbreaking oxytocin experiments on humans, and together the researchers conducted the first oxytocin-infusion study on people, spritzing some fifty male investors with the chemical and giving another fifty or so a placebo before they played an economics game.32 The data were clear. Of the oxytocin sniffers, more than 40 percent showed the maximum amount of trust. In contrast, just 21 percent of the control group did. Plus, the average money transfer was more than 15 percent higher in the oxytocin-spritzed group. Think about it this way: If I had given you a dash of oxytocin before you played the Split or Steal game on the TV game show, you'd be more likely to trust the person that you had just met.

According to Zak, the group of researchers showed for the first time that the hormone actually caused people to place their faith in strangers, and soon overly eager science reporters wrote stories describing the "peptide of love." Television shows heralded the discovery of a trust hormone. But despite all the headlines and all the breathless articles, the real news seems to have been buried: Humans have a built-in system for trusting others.

The wet c.o.c.ktail of oxytocin seemed stuck in my throat. I shook my head and sputtered for a bit, blinking my eyes, waiting for the room to come back into focus. I was at a science lab at Claremont Graduate University, thirty-five miles east of Los Angeles. One of Zak's colleagues, psychologist Jorge Barraza, stood above me, slowly counting off the seconds until he would again fill my nasal cavity with doses of the chemical.

"Okay?" he said.

I nodded.

On that afternoon, Barraza pushed less than a teaspoon of the chemical into my sinuses, and as I sat there in the lab waiting for the hormone to take hold, I wondered what the trust hormone would feel like. Would I see everyone in a gauzy halo of saintly light? Would I suddenly trust my auto mechanic to perform eye surgery? But in the end, the oxytocin didn't inspire a buzz of uninhibited trust. There were no luminous blazes. Adam Penenberg described the experience as a "fuzzy feeling." Barraza told me the effects were "maybe like having half a beer," and for me, honestly, I'm not sure that I felt anything at all.33 A shot of wet chemicals isn't how we usually get a boost of oxytocin, though, and while the science of the hormone is still developing, researchers believe that the chemical is released when we feel a sense of empathy.34 When people experience an emotional connection or a sense of personal engagement, the hormone will kick into gear. Even something as simple as petting your dog can promote oxytocin release.35 And it's in this sense that the hormone appears to play a crucial role in our urge to care for others.36 Or as one neurobiologist, Carsten de Dreu, told me, oxytocin is "truly a social glue."37 By itself, though, the hormone generally produces a bit of a relaxing sensation. The amygdala is one of the most ancient parts of the brain, and it works as a type of fear-tracking device. It tells us what to worry about. Oxytocin appears to influence the area, dialing down our sense of panic and dread. At the same time, oxytocin highlights social cues, and the hormone makes people stare longer into another person's eyes.38 With a bit of oxytocin, people are also better at figuring out if a stranger's face is angry or weepy or just frankly bored.39 But in the end, much of oxytocin's hormonal strength lies within a larger system of social bonding, and what's ultimately powerful about oxytocin is that it works in concert with other pleasure chemicals, such as dopamine. Oxytocin, it seems, serves as a type of systems manager, helping to oversee the hormones that make trust an enjoyable experience, according to neuroscientist Larry Young. The prairie voles provide a chemical recipe for how this works, argues Young, and it seems that there's oxytocin to orchestrate an emotional memory-and a dose of dopamine to make it feel pleasurable.

One summer afternoon, I visited Young at Emory University to find out more. Young worked in a large corner office containing the typical researcher's paraphernalia: graphing calculator, weighty statistics books. But there were also items that would look more at home in a s.e.x therapist's office: a copy of the Kama Sutra, a bottle of Menage a Trois wine. Because for Larry Young, everything goes back to s.e.x, love, and mothering.

The important thing to remember is that evolution is a stingy process, and over time it seems to have recycled our brain circuits devoted to mother-child bonding for other purposes. Put differently, the urge that makes women care for their children became used to sweeten the social ties that keep cooperation going. Young calls this the "mommy circuit," and he believes it's the evolutionary engine behind much of our prosocial ways.

"With these other animals that have oxytocin being released in the brain, it's there to make the mother think that this baby is the most important thing in the world, and I'll do whatever I need to do to take care of that child," Young told me that afternoon, cradling his arms as if he held an imaginary child. "It all sort of originates from that need to direct the mother's attention to the baby." This helps explain why oxytocin works within the brain's broader reward system. Or, as Young told me, "You have the beginning, reward reinforcement, a feel-good kind of pleasure, and then it's maintained because 'I don't really feel good when I'm not around you.'"

A few years ago, Paul Zak flew to England to conduct an experiment. At the time, science writer Linda Geddes was getting married, and she asked Zak to find out if the ceremony would cause oxytocin to spike in herself, in her groom, and among her guests.40 Geddes's wedding was held in a thirty-bedroom baronial mansion in one of England's rural corners, and among the damask curtains, Oriental carpets, and flutes of champagne, Zak took some blood from some of the ceremony's more scientifically inclined guests. Then, right after the wedding ended, he did it all again. It was what Geddes called "a big fat nerd wedding."

After the ceremony, Geddes wondered if her oxytocin levels had gone up at all. After all, a marriage ceremony can be deeply stressful. Zak noted something different: Weddings are a celebration of social bonding, which suggested that oxytocin might increase for everyone who attended. And when the results finally came in a month or so later, there were some wrinkles: The results turned out to line up with how people viewed the event, as Zak suggests, and the bride and groom, along with their close family members, showed clear jumps in their levels of the hormone. But friends of the bride and groom had much less of a gain-and some showed no change at all.

It was a non-experiment experiment. Only thirteen people partic.i.p.ated in the exercise. There was no control group or peer review or testing of a hypothesis. But the anecdote underscores the conditional effects of the chemical. It's contingent on personality and context and situation.41 After a few of the first oxytocin experiments, some believed the hormone might help people with social disorders such as autism. But oxytocin's effects appear to be too dependent on other factors for it to be an off-the-shelf cure, according to researchers like Jennifer Bartz, and while some companies are experimenting with potential applications, it will likely be years before an oxytocin-inspired medical treatment hits the market.

Part of the issue is that one's point of view can alter oxytocin's social power. Consider, for instance, this experiment: Some European researchers gave a shot of the hormone to two groups of men.42 One group was made up of single men; the other group contained men in steady relations.h.i.+ps. The researchers then had the two groups engage with an attractive woman. The results? The committed men stood about six inches farther away from the good-looking woman than the uncommitted men.

In other words, oxytocin is not the hormone of unending trust, as Zak himself notes, and the hormone doesn't always have a trustworthy effect. Some, like science writer Ed Yong, have criticized Zak for calling oxytocin the "moral molecule," and Yong cites experiments in which oxytocin makes people behave in immoral ways.43 One study by Carsten de Dreu shows, for instance, that oxytocin actually made Dutch men more biased against people with Middle Easternsounding names.44 For his part, Zak argues that his critics have not read his work closely enough. Oxytocin is "our social interaction and reciprocation molecule that in many, but not all, circ.u.mstances increases moral behaviors," Zak told me.

In the end, what's clear is that the recent research on oxytocin makes it easy to believe that trust is like money: Either you have it or you don't. But a closer look at the science suggests that our faith in others is like knowing how to code or cook: It's something that we learn over time, something that we need to practice, an expression of our skills and background. When Jennifer Bartz describes the effects of oxytocin, she argues that "context and person matter," and in many ways, the same can be said of trust. It is about who we are as individuals-and the contexts in which we've learned to place our faith in others.

But there's another, just as important conclusion from the oxytocin research: Our faith in others is something deeply human.45 Or, as Zak argues, our faith in others is a part of us, something sparked by our engagement with others. It seems that this notion holds true when trust is an emotional urge. But it also turns out to be at the very center of trust's logical underpinnings. Up until now, we've been exploring the social side of our faith in others. We've looked at our groupish instincts and tried to better understand the role that our brains play in promoting our cooperative ways. But trust doesn't always start with empathy. Sometimes trust is a belief, an expectation of results, a bit of calculation-based faith, and that story begins, oddly enough, more than 150 years ago in a rocky limestone outcropping in the mountains of Tennessee.

Chapter 2.