BRAINPOWER AND INDIRECT RECIPROCITY
Indirect reciprocity is not only a mechanism for the evolution of cooperation but also provides the impetus for the evolution of a big brain. To explain why, I should once again emphasize that cooperation means paying a cost for someone to receive a benefit. Thus, in effect, we buy a reputation. For example, it costs you precious time when you come to the aid of a stranger so that you may end up being late for that pressing appointment with your boss. Or if you give a lift to someone whose automobile has broken down, you could end up with a smear of motor oil on your new silk tie. But the point is that this little generous act secures you a reputation, which might be worth a great deal—more than the initial cost—in the long run.
Thanks to the power of reputation, we help others without expecting an immediate return. If, thanks to endless chat and intrigue, the world knows that you are a good, charitable guy, then you boost your chance of being helped by someone else at some future date. The converse is also the case. I am less likely to get my back scratched, in the form of a favor, if it becomes known that I never scratch anybody else’s. Indirect reciprocity now means something like “If I scratch your back, my good example will encourage others to do the same and, with luck, someone will scratch mine.”
By the same token, our behavior is endlessly molded by the possibility that somebody else might be watching us or might find out what we have done. We are often troubled by the thought of what others may think of our deeds. In this way, our actions have consequences that go far beyond any individual act of charity, or indeed any act of mean-spirited malice. Our behavior is affected by the possibility that somebody else might be watching us. We all behave differently when we know we live in the shadow of the future.
That shadow is cast by our actions because there is always the possibility that others will find out what we have done, whatever the society: it could be the man from the local village gazing down on you from a hill when you helped an old lady; or the woman who was walking by when you carried all those groceries for your wife; or the boy who came to deliver a gift to a neighbor; or the guy who sits at the adjoining desk; or the security guard looking at you through a closed-circuit camera. Each of us also wants our friends, family, parents, and loved ones to know that we are good, helpful people. In coming to the aid of another, or letting another person down, you not only help develop your reputation; you also help perpetuate and bolster the complex and tangled web of indirect reciprocity essential for a large, complex society to run smoothly.
For many people to appreciate your selfless act, and for your reputation to flourish, we need more than language. We need smart and receptive brains. Indirect reciprocity relies on what others think of us. Making a reputation has been shown to engage much of the same reward circuitry in the brain as making money. By being helpful, I obtain the reputation of being a nice, obliging, and considerate person. My behavior toward you, of course, now depends on your reputation and thus what you have done to others: if you have been a cad and a rotter, I am less likely to trust you to deliver. Then again, if we know nothing about someone, we are often willing to give them the benefit of the doubt for the sake of our own reputation.
There is a clear link between this mechanism of cooperation and the evolution of empathy. We need to have a good idea of what is going through the mind of another person in order to understand and appreciate the motivation of a Good Samaritan. “Even though he was rushing home to see his ill mother, he stopped to help that injured man,” “If I had been lying there, bleeding at the curbside, I would have been so grateful for the help of a stranger,” “I could see she was in pain and felt I had to help,” and so on. We require, in the parlance of the psychologists, a “theory of mind,” that remarkable capacity that enables us to understand the desires, motivations, and intentions of others. This mind-reading ability allows us to infer another’s perspective—whether emotional or intellectual.
One can easily envisage how the mechanism of indirect reciprocity can stimulate the evolution of moral systems. The quotation from Luke at the start of this chapter has a direct corollary, known as the Golden Rule, that transcends all cultures and religions: “Do unto others as you would have them do unto you.” The rule pops up in Greek philosophy (“What you wish your neighbors to be to you, you will also be to them,” Sextus the Pythagorean), Buddhism (“Putting oneself in the place of another, one should not kill nor cause another to kill”), Christianity and Judaism (“Love your neighbor as yourself ”), in the Mahabharata of Hinduism (“One should never do that to another which one regards as injurious to one’s own self ”) in the Farewell Sermon of Muhammad (“Hurt no one so that no one may hurt you ”) and in Taoism too (“He is kind to the kind; he is also kind to the unkind”).
The Golden Rule interlinks several ideas: it binds empathy with the idea of reciprocity along with an ironclad faith in the power of indirect reciprocity—if I am good to another person today, somebody will be good to me in the future. In this way, indirect reciprocity has played a central role in the development of our brains, of our ability to lay down memories, and of our language and moral codes. This remarkably potent ingredient of cooperation is at the heart of what it means to be human.
KAHLENBERG
I first came to appreciate the power of indirect reciprocity on a walk with Karl Sigmund in the summer of 1996. We were hiking around the Kahlenberg, a forested hill north of Vienna. The ridge is blessed with breathtaking views of the great city, being part of the Wienerwald, the Vienna woods. We were negotiating a chain of tree-covered hills northeast of the city, bounded by rivers, including the Danube. There are villages here and there, such as one where Beethoven lived (Nussdorf), and taverns (Heurige) are dotted all about, where we could sit down to sip the local wines.
Although this does not sound a likely birthplace for a scientific breakthrough, there is plenty of evidence that the networks of paths that crisscross the forested hills of the Wienerwald are steeped in creative magic. Mahler would walk from the Kahlenberg into the city to conduct opera. Johann Strauss the Younger composed his “Tales from the Vienna Woods” in waltz time. Franz Schubert and Beethoven were also moved by its rolling Arcadian landscapes. A green meadow on a plateau high above the city where the skies open wide is called Himmel (Heaven). There, the young Sigmund Freud managed to convince himself that he had understood the nature of dreams.
During our long meander though heaven, Karl mentioned something that made me stop in my tracks. He suggested that we should extend our work on cooperation to take a close look at indirect reciprocity. I had never heard that expression before but so many thoughts gushed into my mind that I found it intoxicating. I told him that I did not want him to explain too many details. I did not want to know what work might have been done before on this subject, so I could follow through my own line of thinking. I knew exactly what he meant and how the perfect clarity of mathematics could bring this idea into sharp focus. I stopped everything else that I was doing. In my mind a rolling landscape of new possibilities for cooperation beckoned.
I fell in love with this work, which I felt would take our research in a new direction. I was almost consumed by the feeling. Amour did seem to be in the air. For one thing, I was reading The English Patient (“In love, there are no boundaries”). For another, Karl and I had made a poignant discovery during our walk in the lush greenery of the Wienerwald. We stumbled across a little cemetery, where there was an overgrown grave. The headstone was carved with poems and stories to celebrate the memory of Caroline Traunwieser, apparently the greatest beauty of the Vienna Congress of 1815.
Among the many dedications to Caroline was a tribute from the founder of the Austrian Academy of Sciences, Freiherr von Hammer-Purgstall, an Orientalist scholar who supplied Goethe with Persian poetry. He recounted his first heart-skipping encounter with her in a salon: “Never before and never afterwards in my life was I so overwhelmed by the appearance of beauty.” She was adored by all, from poets to officers to the director of the Viennese China Factory (Wiener Porzellanmanufaktur).