BIOLOGY OF TRUST
This question might sound complex, but there is a simple hypothesis about what steers the human brain to trust another human: a hormone called oxytocin.
Oxytocin is produced in the brain’s hypothalamus and stored in the posterior pituitary gland. We know that it helps smooth muscle contractions in childbirth and in breast-feeding mothers. But recently we’ve discovered that its applications go beyond the maternal. It turns out that oxytocin also reduces social anxiety and helps people meet and bond with each other. A man and woman involved in the mating dance are releasing oxytocin; so are friends having a good time at dinner.
Forming relationships like these involves trust, but is there a direct connection between trust and oxytocin?
To find out, my colleagues and I conducted an experiment in which participants took either oxytocin or a placebo. Fifty minutes later, participants played the trust game against four different anonymous partners. They played with real money, with each point worth almost half a Swiss franc.
The results revealed that oxytocin does indeed seem to grease the wheels of trust. Of the 29 investors who had taken oxytocin, 45 percent transferred the maximum amount of 12 points in each interaction. By contrast, only 21 percent of the placebo-group investors did so. The average transfer made by the oxytocin-group investors was 9.6 points, compared with 8.1 points by the placebo-group investors.
Interestingly, the investors’ expectations about the back-transfer from the trustee did not differ between the oxytocin and placebo recipients. Oxytocin increased the participants’ willingness to trust others, but it did not make them more optimistic about another person’s trustworthiness.
The results indicate that oxytocin does indeed somehow help humans overcome distrust. But does oxytocin really increase trust, or does it merely make us feel so good that we lose our aversion to risk and betrayal?
To figure that one out, we conducted a second experiment, in which investors faced the same choices as in the trust game. The investors in this experiment were again in a risky situation, but this time there was no human being on the other side of the table; instead, investors faced a computer that generated random numbers of points. Everything else in the “risk experiment” was identical to the trust experiment.
The result? Investors who’d received oxytocin behaved no differently than those in the placebo groups. We therefore concluded that the effect of oxytocin is, indeed, specific to trusting other people and the willingness to take risks in social situations. Oxytocin does not affect human attitudes toward risk and uncertainty in situations where there are no other human beings involved.
In short, trust is very much a biologically based part of the human condition. It is, in fact, one of the distinguishing features of the human species. An element of trust characterizes almost all human social interactions. When trust is absent, we are, in a sense, dehumanized.
APPLIED TRUST
The discovery that oxytocin increases trust in humans is likely to have important clinical applications for patients suffering from mental disorders like social phobia or autism. Social phobia ranks as the third most common mental health disorder after depression and alcoholism; sufferers are severely impaired during social interactions and are often unable to show even basic forms of trust toward others.
Given the results of our trust studies, the administration of oxytocin, in combination with behavioral therapy, might yield positive effects for the treatment of these patients, particularly in light, too, of its relaxing effects in social situations.
At the same time, however, the results from these experiments raise fears of abuse. Some might suppose that unscrupulous employers or insurance companies could use oxytocin to induce trusting behavior in their employees or clients. Dishonest car salesmen might spray customers with the hormone before steering them toward a lemon.
Fortunately, most of these fears are baseless: the surreptitious administration of a substantial dose of oxytocin—for example, through air conditioning, food, or drinks—is technically impossible. Of course, one could always force the spray up another’s nose. But it’s safe to say that this would alarm recipients enough to override any glow they might get from the oxytocin.
It is more likely that advertisers might find ways to cleverly design stimuli to trigger the release of oxytocin in consumers through, for example, strategically placed smiling faces or warm handshakes or perhaps even by measuring people’s oxytocin levels in focus groups. All this might make these consumers more inclined to trust the claims made by the advertisers. Of course, advertisers (and most socially intelligent humans) have always intuitively understood ways to manipulate perception and build trust; this just gives them one more tool for their kit. However, knowledge can cut both ways: by better understanding the underlying biological mechanisms of these stimuli, research into oxytocin could be even more useful for protecting consumers from the manipulative strategies of marketing departments.
To some people, these findings about oxytocin might raise another concern: that trust is not subject to rational control—that it’s “all hormones.” This seems to stand in stark contrast to the traditional idea of trust being the outcome of a cognitive, rational process.
In my view, trust is both, just like other human social behaviors. We cannot deny that many of our decisions are governed by cognitive processes, which in the case of trust take into account the available information about the trustee’s motivation, the likelihood of a repeated interaction, and so on.
Nevertheless, research like this shows that our behavior is also influenced by a large number of very complex, yet identifiable, biological processes. Future research should help us understand how cognitive and biological processes interact in shaping our decisions about whom to trust.
But there’s no denying the important role trust plays in cooperative behaviors or that humans have a deeply rooted ability to trust. It’s up to us to earn that trust from one another.
PAY IT FORWARD
Robert A. Emmons
ELIZABETH BARTLETT is a professor of political science at a midwestern university. At the age of 42, her irregular heartbeat had become life-threatening. A heart transplant was her last hope, and she was fortunate to receive one. In a book chronicling her journey, she writes that she felt thankful for her new lease on life—but simply feeling thankful wasn’t enough.
I have a desire to do something in return. To do thanks. To give thanks. Give things. Give thoughts. Give love. So gratitude becomes the gift, creating a cycle of giving and receiving, the endless waterfall. Filling up and spilling over and perhaps not even to the giver but to someone else, to whoever crosses one’s path. It is the simple passing on of the gift.
What Bartlett describes is true gratitude. As this brief passage illustrates, gratitude is more than a pleasant feeling; it is also motivating. Gratitude serves as a key link between receiving and giving: it moves recipients to share and increase the very good they have received. Because so much of human life is about giving, receiving, and repaying, gratitude is a pivotal concept for our social interactions. The famed sociologist Georg Simmel declared that gratitude is “the moral memory of mankind.” If every grateful action, he went on to say, were suddenly eliminated, society would crumble.