The Evolutionary Roots of Altruism

Ciju Cherian / Solent News / Rex Features

With a little teamwork, these ants turn themselves into a bridge for their friends to walk over in Kerala, India. 

Does Altruism Exist? Culture, Genes, and the Welfare of Others
By David Sloan Wilson
192 pp. Yale University/Templeton Press $27.50

David Sloan Wilson opens his new book, Does Altruism Exist?, with an old conundrum that has animated many late-night dormitory debates: If helping someone gives you pleasure, gains you points for an afterlife, and enhances your reputation, is it really altruism? Wilson wisely decides to put acts before motives: “When Ted benefits Martha at a cost to himself, that’s altruistic, regardless of how he thinks or feels about it.” Great. But what does “cost” mean in that sentence? Does it mean “cost” after considering all those benefits, or not?

Wilson believes that to answer this question, we must turn to evolutionary theory, and especially to a theory known as group selection, which holds that better adapted groups produce more offspring, with the result that their traits are passed on. The implications are far-reaching. If group selection is correct, it follows that humans and other group-living creatures are fundamentally not selfish but cooperative and even altruistic—that we human beings owe our existence to distant ancestors who were members of groups that succeeded because they were better able to cooperate than other groups.

Group selection departs from the more familiar model of individual selection that sees the evolutionary prize going to the individual, male or female, who has more surviving offspring, regardless of health and life-span, much less altruism. Yet another variant of Darwinian theory reduces evolution to what the biologist Richard Dawkins famously called “the selfish gene.” In this view, the true competition to reproduce is at the level of the gene, and an organism is only a gene’s way of making a copy of itself.

Selfish-gene theory allowed, however, for an explanation of altruism that arose in the 1960s and became known as “kin selection.” If a gene affects altruism in such a way that the altruism is more likely to be directed at close relatives, the gene can spread in the population despite the cost imposed on the altruist. For example, if an individual is 99 percent likely to die while saving two full siblings with 100 percent certainty, that’s enough for the sibling-saving gene to spread slowly but surely over evolutionary time.

In humans we call this nepotism. And no, it doesn’t matter that there is no one gene for kin-directed altruism. There can be hundreds of genes, each with a small effect, just as there are for height or depression. Environments during childhood can have a whopping effect on each of these three traits as well, but none of this changes the mathematics or the long-term predictive value of kin selection theory. Other approaches to the evolutionary puzzle of altruism also appeared in the next half-century: the ability to expect and receive reciprocal altruism, the benefits to an individual’s reputation, cooperation in games where the cumulative payoff beats defection, and other models.

So recent decades produced a lot of ways of explaining the evolution of limits on selfishness, and with one exception they all involve some benefit to the individual, or at least to the genes, from restraining raw selfishness. But Wilson considers these explanations inadequate, and his way out is to turn to his decades-long commitment to that alternative process: group selection. To be exact, he defends multilevel selection: He doesn’t reject selection at the level of the gene or the individual, but he believes that group selection plays a very large role, especially in social behavior.

In other words, far from holding that natural selection operates mainly on genes blindly replicating themselves or on individuals struggling for life and, more important, reproduction, Wilson is one of a growing number of distinguished scientists who believe that competition among superorganisms—functionally organized groups—is key to understanding evolution. The idea of group selection favoring cooperation isn’t new; it goes back at least to Peter Kropotkin, a Russian evolutionist of the early 20th century, and to some remarks of Darwin’s. Before kin selection was formally proposed in the 1960s, a British ornithologist, V. C. Wynne-Edwards, tried to explain much about avian social life by reference to adaptive group functioning. For example, he asked how the evolution of submissive behaviors could otherwise be explained if dominance leads to reproductive success. Another British ornithologist, David Lack, replied that the beta animal passes on submissive displays, since the alpha can’t monopolize reproductive success forever—he may age or get hurt—while the bowing and scraping beta can live to reproduce another day. In other words, Lack and others stood by individual selection as sufficient. Due to opposition by leading evolutionists at the time, and despite lifelong proponents like David Sloan Wilson, group selection languished.

But it is being revived. In the journal Nature in 2010, Martin Nowak, Corina Tarnita, and E.O. Wilson tried to show that kin selection is irrelevant to explaining the phenomenon that it seemed for half a century most suited for: extreme cooperation and self-sacrifice in insect colonies. Explanations of kin selection often start with ants and bees, because colonies consist largely of hyper-siblings so closely related to each other that genes underlying sacrifice can be passed down by near kin who live to reproduce. Nowak et al.’s mathematical models aimed to prove that relatedness doesn’t matter—colonies just compete as groups—and they extended their reasoning to dismiss kin selection generally.

Two letters appeared a few months later, one with 137 authors, the other with nine, vigorously defending kin selection and summarizing evidence for it. Among these signers were many of the most recognizable names in evolutionary biology. That doesn’t make them right, of course. Nor do the papers published since decide the question. They include more work in favor of group selection (in spider colonies, for instance) as well as new empirical work and reviews supporting kin selection in vertebrates as well as insects. There have also been theoretical claims that group selection and kin selection are mathematically equivalent, and that there is a narrow theory of kin selection that is wrong but a general one that is right.

This is a lively debate. If you search on “The False Allure of Group Selection,” you will find not only Steven Pinker’s critique of the theory but also many lengthy comments from leaders in evolutionary studies, pro and con. The controversy is raging, and I am not proposing to tell you who is right. But in his new book, David Sloan Wilson claims the debate is all over:

The controversy over group selection is receding into the past and eventually will be forgotten except from a historical perspective, like the controversies over the Copernican view of the solar system, Darwin’s theory of natural selection during the late nineteenth and early twentieth centuries, and the theory of continental drift during the early twentieth century. For this reason I am able to offer a postresolution explanation for the evolution of altruism in a short space …

It’s fine for Wilson to present his own view, but to declare victory is a little disingenuous. And implying that the numerous scientists who have little use for group selection are like anti-Copernicans is just a rhetorical trick—and a rather ungenerous one for a book on altruism.

Everyone in evolutionary science believes in multilevel selection, especially at the levels of the gene and the individual, and few rule out group selection completely; it’s a question of how important group selection is. Wilson defines his main evolutionary principles this way: “Natural selection operating within groups tends to undermine group-level functional organization,” and “Group-level functional organization evolves primarily by natural selection between groups.” A shorter version comes from a paper he wrote with another famous Wilson, Edward O.: “Selfishness beats altruism within groups. Altruistic groups beat selfish groups. Everything else is commentary.”

But consider for a moment some real human instances. After stealing vast tracts of land from Native Americans, largely slaughtering them in the process, competitive Euro-Americans held land rushes in which the conquerors raced as fast as they could to plant flags and claim hundreds of acres each. This land was stolen from people who lived in far more cooperative groups, believed much less in individual property rights, and often viewed land as a resource held in common. They vied with each other before white culture came, and perhaps more cooperative groups prevailed. But faced with a less cooperative group than any of theirs, the Native Americans lost.

On the other hand, the Nazis who murdered most of the Jews of Europe were very organized indeed, much more so than the communities they destroyed. Some scientists project group replacement back through human evolution. Samuel Bowles and Herbert Gintis, in A Cooperative Species, explain the evolution of cooperation as a result of what they believe was extreme group conflict, with the elimination of less cooperative groups throughout the formation of our species.

According to Wilson, we cannot have gotten to our present level of human cooperation and altruism without competition among groups in which more cooperative ones prevailed. He is not naïve about conflict: “Everyday life and the annals of history are replete with examples of individuals and factions that succeed at the expense of their groups, despite the arsenal of social control mechanisms designed to thwart them.” But altruism is safe in the end, according to Wilson, because only groups that control these disruptive forces can succeed against other groups, which will disintegrate, dwindle, or be destroyed.

Leaving aside how plausible his scenario is, we have known at least since sociologist Lewis Coser published his 1950s classic, The Functions of Social Conflict—backed by long historical experience—that group conflict tends to bring out the best and the worst in people. Sure, groups at war cohere quite beautifully. The difficulty is that the group has to be really nasty to outsiders. If you need group conflict to evolve cooperation, why don’t you need group conflict to sustain it? And if you do, the logic of group selection seems no help in getting to the kind of cooperation that includes all humanity—the group that is not at war because there is no outsider left to fight.

Wilson’s view is that because group selection preceded human evolution, it provides the evolutionary key. All of us who study human origins would love to be able to say what the key was. Ever since Darwin, scientists have come up with plausible explanations: bipedal walking, rapid brain expansion, tool-making, language, religion, hunting, art, monogamy, helpless infants, group child care, menstruation, concealed ovulation (instead of estrus or “heat”), menopause, grandmotherhood, aid in childbirth, and many others. Of these, bipedal walking and (probably) hunting preceded brain expansion by several million years. The rest is speculation. Group cooperation is just one of a long list of  suspects.

Wilson follows the great evolutionists Ernst Mayr and Niko Tinbergen in urging us to carefully separate ultimate (evolutionary) causes from proximate causes, such as those involving individual motives. As Wilson well knows, the extant evolutionary explanations of altruism (or cooperation) are manifold. Since altruism has evolved and persisted, it must be adaptive, which means it has increased the frequency of genes that underlie it. This, Wilson concedes, applies as much to group selection as to individual or kin selection. But he also knows that the proposed (and to some extent proven) ultimate adaptive value of altruism has included survival of kin, expected reciprocity, and reputation. All are ultimate causes, none depend on motives, and none require group selection.

Suppose I’m a young man on a date and I drop an overly generous bill in a street musician’s guitar case. Is this irrelevant to my personal reproductive success? If I help a colleague manage a difficult student, is it just for the good of the college, or might I one day get help in return? If I die in a suicide attack and my family is praised, is group selection the only way to account for my behavior?

Remember, none of this is about motives; it is all about ultimate causes. There is also a kind of non-causal explanation known as mismatch: We evolved for so long in groups of kin that we can no longer function any other way, even among unrelated friends and colleagues. Since, unlike many species, we know kin by association—not by odor or other indelible signals—mismatch is possible. It’s not a very elegant explanation, but it may be right.

Expanding on the implications of his argument, Wilson makes a spirited defense of religion against aggressive atheism, claiming among other things that religions promote in-group altruism. (Full disclosure: I agree and am working on a book that makes that among other points.) He also gives us a reasoned critique, based on behavioral economics, of the Ayn Randian (really, Leon Walrasian) notion of Homo economicus, the everyday hero who makes the world run handsomely through unrepentant selfishness. In developing his argument for group selection, Wilson draws on Elinor Ostrom’s work on the “tragedy of the commons.” A leader in game theory and winner of the Nobel Prize for economics, Ostrom showed that by instituting certain rules, people can avert what some have seen as an inevitable outcome—selfishness depleting and destroying a shared resource. So, even under rational economic theory, it does not have to be everyone for her- or himself.

In one of the book’s best chapters, we learn about what Wilson and his colleagues have done in Binghamton, New York, studying and promoting prosocial behavior (altruism without regard to motives) among disadvantaged students and improving lives and neighborhoods as a result. But we are told that a particular theory of evolution supported this work, even after a chapter showing that religions have done similar good work while in some cases denying evolution, and another showing that governments and philanthropists have done great good while ignoring evolution.

In the book’s final chapter, “Planetary Altruism,” Wilson takes his argument to what he sees as its logical conclusion. “The need to manage self-organizing processes might seem like a contradiction in terms,” Wilson writes, “but it follows directly from evolutionary theory.” The management in question seems to be motivated by a belief in the importance of group selection. Yet Wilson has also acknowledged, “All sorts of selfish motivations can result in a desire to help others.” So, in efforts to manage the planet, why not rely on selfishly motivated altruistic actions tempered by game theory’s evolutionarily stable strategies? That approach might have the same effect and be consistent with other views of evolution. We can agree that planetary altruism (or at a minimum, cooperation) is vital for human survival, but we don’t need a particular, still highly contentious, evolutionary theory to promote it.  

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