SuperCooperators

Altruism, Evolution, and Why We Need Each Other to Succeed

Martin Nowak, Roger Highfield

• Editorial: Free Press
• Año: 2011
• ISBN:
  9781439110171
• Categoría: Philosophy
• Categoría: Philosophy & Ethics in Science

EVOLUTION IS OFTEN PRESENTED AS A STRICTLY COMPETITIVE ENDEAVOR. This point of view has had serious implications for the way we see the mechanics of both science and culture. But scientists have long wondered how societies could have evolved without some measure of cooperation. And if there was cooperation involved, how could it have arisen from nature "red in tooth and claw"? Martin Nowak, one of the world's experts on evolution and game theory, working here with bestselling science writer Roger Highfield, turns an important aspect of evolutionary theory on its head to explain why cooperation, not competition, has always been the key to the evolution of complexity. He offers a new explanation for the origin of life and a new theory for the origins of language, biology's second greatest information revolution after the emergence of genes. SuperCooperators also brings to light his game-changing work on disease. Cancer is fundamentally a failure of the body's cells to cooperate, Nowak has discovered, but organs are cleverly designed to foster cooperation, and he explains how this new understanding can be used in novel cancer treatments. Nowak and Highfield examine the phenomena of reciprocity, reputation, and reward, explaining how selfless behavior arises naturally from competition; how forgiveness, generosity, and kindness have a mathematical rationale; how companies can be better designed to promote cooperation; and how there is remarkable overlap between the recipe for cooperation that arises from quantitative analysis and the codes of conduct seen in major religions, such as the Golden Rule. In his first book written for a wide audience, this hugely influential scientist explains his cutting-edge research into the mysteries of cooperation, from the rise of multicellular life to Good Samaritans. With wit and clarity, Nowak and Highfield make the case that cooperation, not competition, is the defining human trait. SuperCooperators will expand our understanding of evolution and provoke debate for years to come.

Five Ways to Solve the Dilemma

CHAPTER 1
Direct Reciprocity—Tit for Tat

It will have blood; they say, blood will have blood.

—Shakespeare, Macbeth

In the pitch darkness, the creatures take flight. They shun the moonlight, making the most of their sense of smell to track their victims, then land nearby to stalk them. After a quick loping run on all fours they latch on to their prey. Using a heat sensor on the nose, each one can tell where the blood courses closest to the surface of the victim’s skin. Often a meal begins with a quick bite to the neck. There they can hang for up to half an hour, using their long grooved tongues like straws to lap fresh warm blood. Over several nights they return to sup on the same wounds, and it is thought that they are able to recognize the breathing sounds of their victims in the same way as we use the sound of a voice to recognize each other.

What I find most extraordinary of all about vampire bats is what happens when they return to their roost, where hundreds, even thousands of them congregate, suspended upside down. If one member in the roost is unable to find prey during the night’s hunt, its peers will regurgitate some of their bloody fare and share it. The exchange of blood among the bats was first revealed in studies conducted in the early 1980s by Gerald Wilkinson of the University of Maryland. During fieldwork in Costa Rica, Wilkinson found that, on any given night, a few percent of adult bats and one-third of juveniles fail to dine. They rarely starve, however, since well-fed vampire bats disgorge a little precious blood to nourish their hungry peers. What was neat was that his experiments suggested that bats are more likely to share blood with a bat that has previously fed them (the bats spend time grooming each other, paying particular attention to fur around the stomach, enabling them to keep tally).

This is an example of what I call direct reciprocity. By this, I mean simply the principle of give-and-take. When I scratch your back, I expect you to scratch mine in return. The same goes for blood meals among bats. This form of reciprocity is recognized in popular sayings, such as “tit for tat” and the idiom “one good turn deserves another.” The Romans used the phrase quid pro quo—“something for something.” As the vampires suggest, this kind of cooperation dates back long before Romulus and Remus, long before the rise of modern humans.

For direct reciprocity to work, both sides have to be repeatedly in contact so that there is an opportunity to repay one act of kindness with another. They might live in the same road, or village. Perhaps they work together. Or they may encounter each other every Sunday in church. In the case of the bats, they hang about the same cave or hollow. In that way, they can form a “contract” based on helping each other.

The bats are one often cited example of direct reciprocity in nature. Another can be found on coral reefs, where fish of all kinds visit “cleaning stations” where they are scrubbed of parasites by smaller varieties of fish and by shrimps: the former get cleaned of pesky parasites and the latter get a free meal. When a wrasse tends a great grouper, the little cleaner sometimes swims into the gill chambers and mouth, demonstrating remarkable faith that it is not going to be eaten. When the grouper wants to depart, it tells its cleaner that it wants to go by closing its mouth a little and shaking its body. It does this even when it is in danger of being attacked. A safer way to proceed would be to gulp down the cleaner and leave immediately. The first strategy would be a form of cooperation, the second a form of defection.

The nuisance of parasites—ticks—has led to the emergence of another instance of this mechanism at work, in the form of reciprocal grooming, this time among impala, a kind of antelope found in Africa. And when it comes to our closest relatives, textbooks are crammed with examples. One was reported in 1977 by Craig Packer in the Gombe Stream Research Centre, Tanzania, where there has been a long-term study of olive baboons, so named because of their distinctive fur. Packer, now at the University of Minnesota, reported how one male will help another who had previously come to his aid in ganging up on more senior baboons, so that one of them can have sex with the senior’s female. Even though the helper will not have sex immediately after forming a coalition, he still cooperates because he expects the favor will be returned.

Sri Lankan macaques Macaca sinica will tend the wounds of a fellow male in order to secure the latter macaque’s support in future conflicts. Unsurprisingly, juvenile males are especially attentive to the injuries of hefty adults, who can provide more muscle in a future fracas. One study of macaques in Kalimantan Tengah, Indonesia, went so far as to suggest that males were more likely to mate with females that they have previously groomed, the grooming being a kind of payment for sex, a finding given the colorful interpretation that the “oldest profession”—prostitution—seems to date back long before humans.

Male chimpanzees share meat to bind social alliances, and there is some evidence that they increase the degree to which they cooperate in line with how much a partner has been helpful toward them. Reciprocity can be exchanged in all kinds of currencies, such as grooming, support in fights, babysitting, warning, teaching, sex, and of course food. Frans de Waal of Emory University, Atlanta, observed how a top male chimpanzee, Socko, had more chance of obtaining a treat from his fellow chimp May if he had groomed her earlier that day.

There are caveats, however. One is that different scientists use terms such as reciprocity in various ways. Another is that, when it comes to observing behaviors in the wild, it can take many lengthy and detailed studies to understand what is really going on. Tim Clutton-Brock, a professor of ecology and evolutionary biology at Cambridge University, says that it can be hard to sift concrete examples of reciprocity from the illusory ones that can be explained another way.

Let’s take Craig Packer’s inspirational olive baboon research, for example. Packer had originally thought that the males were trading favors in their pursuit of sex. His original argument went that the allies switch roles, so that each one benefits from the association. But follow-up studies suggested that the cooperating males actually compete with each other when it comes to snatching the prize. The only way they can have an opportunity to mate is to join forces and to cooperate, true enough. But once the existing consort is driven off, then it is every man for himself when it comes to getting the girl. Packer puts it like this: “In this scenario, cooperation is like a lottery, and you can’t win if you don’t buy a ticket. Because two against one gives very good odds of success, the price of the ticket is very low compared to the value of the prize. Participate in enough lotteries of this sort, and you will always come out ahead—and so will your partners.”

RECIPROCITY RULES

Oliver: I remember you!

Grocer: And I remember you too. Now get out of my store and stay out!

Oliver: Oh, don’t be like that. Let bygones be bygones. Let’s help each other. You have a business, and we have a business. We’ll send people to your store, and you send people to our store. What do you say?

Grocer: You mind your business and I’ll mind my business. Now get out before I throw you out!

—Laurel and Hardy in Tit for Tat

One way to determine which examples of direct reciprocity are real is to think about the qualities that are necessary for this mechanism to work. The evolution of cooperation by direct reciprocity requires that players recognize their present partner and remember the outcome of previous encounters with him or her. They need some memory to remember what another creature has done to them, and a little bit of brainpower to figure out whether to reciprocate. In other words, direct reciprocity requires reasonably advanced cognitive abilities.

I am sure that enough cognitive capacity is available in certain species of birds and among our closer relatives, most certainly the great apes. I am certain there is enough grey matter when it comes to human beings. If Harry does Fred a favor, Fred can remember what Harry looks like. He can also remember his good deed and how Harry has behaved in the past. Fred certainly has sufficient cognitive capacity to figure out from what he can remember if Harry is trustworthy and then tailor his behavior accordingly.

When it comes to the soap opera of everyday life, examples of direct reciprocity are everywhere. The running of a household depends on a ceaseless, mostly unconscious bartering of goods and services. In the kitchen, the one who cooks is often spared the drudgery of the washing up and vice versa. The concord among the members of a student house depends on everyone contributing equitably to cleaning duties, a food kitty, or whatever. If a friend helps us to move house, there is an obligation on us to help to pack his furniture when it is time for him to move, or unpack his crates. Families often harbor expectations that children will reciprocate for the care they receive as babies and as children by looking after their elderly parents.

When we receive invitations to dinner, a night at the theater, and so on, there comes an unwritten obligation to reciprocate in some way, in kind or with a treat in return. If a colleague at work hands you a gift-wrapped present, you make a mental note to reciprocate when her birthday comes around. When someone holds open a door, or gestures toward the mountain of food in a buffet, and says, “After you,” many instantly reply, “No, you go first.” The same sense of duty to reciprocate helps to make the ritual gift giving at Christmas expensive. And it can be found in bigger tribes and groups of people: businesses may have long-term contractual obligations with each other; governments make treaties with one another; and so on and so forth.

We repay meanness in the same coin. This is best reflected in the phrase “an eye for an eye, a tooth for a tooth,” from Exodus 21:24–27, in which a person who has taken the eye of another in a fight is instructed to give equitable recompense—his own. In the code of Hammurabi, created by an ancient Babylonian king, the principle of reciprocity is expressed in exactly the same way (“If a man put out the eye of another man, his eye shall be put out” and “If a man knocks the teeth out of another man, his own teeth will be knocked out”). One can see the same tit-for-tat logic in the idea of a “just war,” where the methods used to prosecute a conflict are proportionate to a given threat.

Unsurprisingly, given its central role in human life, reciprocity has inspired comedy. The vintage duo Laurel and Hardy used acts of slapstick revenge to give their movies a satisfying climax. One of their short films released in 1935 revolves entirely around reciprocal retaliations. Appropriately enough, the film is titled Tit for Tat.

So there’s plenty of evidence that we live in a reciprocating world. But, of course, it does not always follow that another player in the game of life will reciprocate. Because there is a cost involved in helping another, cooperation always comes with the threat of exploitation. Why should anyone share in hard work or return a favor? Why not cheat? Why not let the other guy toil and sweat, so you can reap the rewards of his hard work and not bother to do a similar favor? In fact, why do we bother with helping others at all?

After all, natural selection puts a premium on passing genes to future generations, and how can it shape a behavior that is “altruistic” in the long term when defection offers such tempting short-term rewards? In modern society, a hefty apparatus of law and order ensures that this temptation to cheat will remain, in general, resistible. But how can direct reciprocity work in the absence of authoritarian institutions? Why, in the case of cleaning stations on the reef, do clients refrain from eating their helpful cleaners after the little fish have discharged their duties?

This issue has been discussed for decades but, from the perspective of my field, was first framed the right way in a paper by Robert Trivers, an American evolutionary biologist. A fascinating character, Trivers, who suffers from bipolar disorder, became steeped in controversy because of his friendship with the leader of the Black Panther Party, Huey Newton. Today, at Rutgers, the State University of New Jersey, he specializes in the study of symmetry in human beings, “especially Jamaican.” Steven Pinker hails Trivers as one of the greats in western intellectual history.

One of the reasons Pinker rates him so highly is a milestone paper that Trivers published in The Quarterly Review of Biology in 1971, inspired by a visit to Africa, where he had studied baboons. In “The Evolution of Reciprocal Altruism” Trivers highlighted the conundrum of cheats by borrowing a well-known metaphor from game theory. He showed how the conflict between what is beneficial from an individual’s point of view and what is beneficial from the collective’s point of view can be encapsulated in the Prisoner’s Dilemma. As I explained in the last chapter, it is a powerful mathematical metaphor to sum up how defection can undermine cooperation.

At that time, Trivers did not refer to direct reciprocity but used the term “reciprocal altruism,” where altruism is an unselfish concern for the welfare of others. Although altruism is the opposite of the “selfish” behavior that underpins the more traditional view of evolution, it comes loaded with baggage when it comes to underlying motive. Over the course of this book I hope it will become clear that, although it seems paradoxical, “altruistic” behavior can emerge as a direct consequence of the “selfish” motives of a rational player.

Among the mechanisms to escape from the clutches of the Prisoner’s Dilemma, the most obvious one, as I have already hinted, is simply to repeat the game. That is why cooperation by direct reciprocity works best within a long-lived community. In many sorts of society, the same two individuals have an opportunity to interact not once but frequently in the village pub, workplace, or indeed the coral reef. A person will think twice about defecting if it makes his co-player decide to defect on the next occasion, and vice versa. The same goes for a fish.

Trivers was the first to establish the importance of the repeated—also known as the iterated—Prisoner’s Dilemma for biology, so that in a series of encounters between animals, cooperation is able to emerge. He cited examples such as the cleaner fish and the warning cries of birds. What is remarkable is that Trivers went further than this. He discussed how “each individual human is seen as possessing altruistic and cheating tendencies,” from sympathy and trust to dishonesty and hypocrisy.

Trivers went on to suggest that a large proportion of human emotion and experience—such as gratitude, sympathy, guilt, trust, friendship, and moral outrage—grew out of the same sort of simple reciprocal tit-for-tat logic that governed the daily interactions between big fish and the smaller marine life that scrubbed their gills. These efforts built on earlier attempts to explain how reciprocity drives social behavior. In the Nicomachean Ethics, Aristotle discusses how the best form of friendship involves a relationship between equals—one in which a genuinely reciprocal relationship is possible. In Plato’s Crito, Socrates considers whether citizens might have a duty of gratitude to obey the laws of the state, in much the way they have duties of gratitude to their parents for their existence, sustenance, and education. Overall, one fact shines through: reciprocity rules.

THE ITERATED DILEMMA

Since the Prisoner’s Dilemma was first formulated in 1950, it has been expressed in many shapes, forms, and guises. The game had been played in a repeated form before, but Trivers made a new advance when he introduced the repeated game to an analysis of animal behavior. This iterative Prisoner’s Dilemma is possible in a colony of vampire bats and at the cleaning stations used by fish on a reef, which were the subject of Trivers’s paper.

However, the implications of what happens when the Prisoner’s Dilemma is played over and over again were first described before Trivers’s analysis in 1965 by a smart double act: Albert Chammah, who had emigrated from Syria to the United States to study industrial engineering, and Anatol Rapoport, a remarkable Russian-born mathematician-psychologist who used game theory to explore the limits of purely rational thinking and would come to dedicate himself to the cause of global peace. In...