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Darwinian Virtues

What evidence, then, does Ridley present to support his claim about cooperative instincts? Some of this evidence involves the kind of “just-so” stories that sometimes invite accusations of circular reasoning from critics of sociobiology and evolutionary psychology. There is a big difference, however, between adaptationist stories that are used as guides to testable evolutionary hypotheses and ad hoc stories invented solely in order to bolster untested claims. Without independent evidence, it is a just-so story that “the eye has evolved for seeing.” But based on convincing morphological evidence of the way eyes developed from cells vaguely sensitive to light to organs capable of seeing, this adaptationist story turns out to be true for more than forty different evolutionary lineages, from arthropods to vertebrates.

What is impressive about Ridley’s argument is the fact that his phylogenetic account of cooperation is strengthened by at least three independent lines of evidence. The first comes from neurobiology. Some people with brain injuries to the prefrontal lobe display a peculiar cognitive deficit: they are emotionally unresponsive. Yet these patients can generally reason like anyone else, and suffer no deficiencies in memory or intelligence. These people are unable, however, to make decisions about simple matters. Their broken brains trap them in endless rational debates about pros and cons.8 Emotions have an important role in decision making because our reasoning abilities evolved in tandem with the visceral reactions that reinforce our ability to distinguish fair from unfair.

A second line of relevant evidence involves recent research on cognitive functioning. As Darwin himself understood a century ago, some of the most persuasive evidence for evolution involves manifestations of imperfect design. For sociobiologists such as Ridley, it is always expedient to be able to show that, in engineering the architecture and functioning of our brains, a wise Creator could have done a much better job than the forces of evolution. Evolutionary solutions tend to reflect the unplanned nature of evolutionary change, as well as the inability of evolution to anticipate the future. Humans are no exception to this rule and display evidence of poor cognitive design: we are not very good at certain types of abstract reasoning. Given the task of figuring out a simple mathematical formula that determines a sequence of numbers, experimental subjects typically fail to employ the logic of falsification, which is the most efficient way to reach the correct answer. When the task is recast as an exercise in detecting whether someone has violated a social contract (such as agreeing to provide a service in return for a specific remuneration), people suddenly reason more proficiently, focusing on evidence that would clearly establish that the other person is cheating.9

Similar research has prompted economists such as Robert Frank to recognize that economic behavior cannot be explained solely by rational choice. Instead, trust, guilt, and an occasional desire for revenge all play an important role in economic decisions. (One may wonder why economists were so late in coming to a conclusion that many of us think is self-evident, but we should bear in mind that a tendency to prefer rational explanations for human behavior has been dear to Western thinking since the Scientific Revolution.) A third line of evidence, which Ridley oddly overlooks, is also pertinent to his argument about innate virtue. As I have previously mentioned, twin studies have shown that altruistic tendencies are heritable, which strongly suggests that they have evolved by natural selection.10

Ridley’s treatment of game theory, and its special relevance to cooperative behavior, sets the stage for the last half of his book. There he successively treats tribal tendencies, war, trade, environmental destruction, and finally the proper role of government. This latter part of the book revolves around questions that political philosophers have asked themselves for centuries. Are human beings noble savages who were subsequently corrupted by civilized life (Rousseau’s view), or are we innately selfish and in need of a Hobbesian Leviathan to curb our unruly desires? Ridley rejects this hackneyed dichotomy. Our genes may be the mechanisms by which our reproductive interests are selfishly achieved, but they go about achieving these interests through genuinely cooperative behavior. For Ridley, the deed is what ultimately counts. Because of our innate propensity to cooperate, Ridley argues, we are a “groupish” species with basically good intentions. But groupishness entails a Faustian bargain, namely, our tendency to engage in “tribal thinking.” Because we are both capable of cooperating and, in his view, are hard-wired to be wary of defectors, we tend to trust those people whom we know well. Such trust was originally limited to the band or tribe, which is no longer the case today. Still, strong group loyalties often distinguish the people we trust from those we do not, and thus underlie our regrettable tendency toward xenophobia.

Group loyalties are maintained, Ridley argues, by the human inclination toward conformity, which is more pronounced than in any other primate. We tend to conform because we place high value on the opinions of others and especially covet our reputations for trustworthiness and allegiance to the group. Religions, in particular, tend to stress “in-group” versus “out-group” thinking, intensifying our groupish tendencies. Although religions emphasize the importance of cooperation among true believers, they also tend to stir up animosity between true believers and nonbelievers. Even Christianity, with its noble ethos of “love thy neighbor,” has been the cause of many deadly crusades against non-Christian groups. Similarly, during the Reformation, Catholics thought it was their solemn duty to burn reform-minded Protestants as heretics.11

One weakness in Ridley’s argument involves his failure to discuss in sufficient detail just how genetic explanations of cooperation and xenophobia can be reconciled with evidence of dramatically changing social attitudes over time. During wars, for example, ethnic and national groups have regularly pushed xenophobia to genocidal extremes, as occurred in Nazi Germany, and as goes on today in Bosnia, Rwanda, and other parts of the world. But Germany and some of its former enemies are now loyal allies, and the same can be said of Japan and the United States. Although such evidence is not a fatal blow to Ridley’s argument, these kinds of historical transformations call for analysis of how historical and cultural experiences within different social groups lead to cooperation rather than xenophobia. Human beings seem equally capable of both strategies, so genetic dispositions are never the full story (as Ridley would agree).

One contingent mechanism that Ridley does discuss in this connection is social exchange. Because humans appreciate the advantages deriving from the division of labor, we often exchange goods with our closest neighbors. Archaeological evidence suggests that trade is an ancient proclivity, dating back at least two hundred thousand years (based on the considerable distances that stone tools traveled from their quarries). Even the fierce Yanomamo of Venezuela, Ridley notes, maintain strong village alliances that owe much of their durability to trade.

In one of the most interesting chapters of his book, Ridley addresses the issue of environmental devastation, which he recasts as a version of the prisoner’s dilemma. We would all be better off if we agreed not to overexploit our environment. Yet we generally do so anyway, given that the other guy is likely to beat us to it; and so arises the “tragedy of the commons.” When a Pleistocene hunter finally killed the last woolly mammoth to feed his hungry family, he would have been foolish to spare this mammoth’s life only to see his loss become someone else’s gain. The record of mass extinctions during the late Pleistocene points strongly to overhunting by man, with 73 percent of the large mammals disappearing within a few thousand years of Homo sapiens‘s colonization of the New World. Similar waves of mass extinction among flightless birds and mammals followed the arrival of humans in Madagascar, Australia, New Zealand, and the Polynesian islands.

Still, according to Ridley, responsible ecological stewardship is possible owing to our predilection for cooperative behavior. The key, he claims, is private ownership of property. Ridley reviews a wide variety of examples—from Maine lobstermen to Nepalese rice farmers—to show that people tend to protect their environments whenever they can control its resources and also appreciate the consequences of their own excesses. His most convincing example involves the conservation of big game in Africa. Most government efforts to eliminate poaching for ivory and bush meat have been “an unmitigated disaster,” Ridley asserts. In Zimbabwe, however, the title to wildlife has been given back to local communities, which allow sport hunters to bid for the right to shoot wild game. Villagers now work hard to protect their wildlife from poachers, and the Zimbabwe program has been a big success. Unfortunately, many cases of environmental management do not have such happy outcomes, and Ridley’s provocative treatment of this subject is too incomplete to be convincing.

Ridley concludes his book with a chapter “in which the author suddenly and rashly draws political lessons.” Building on his argument about ecological stewardship, Ridley argues that the best government is one that devolves responsibilities back to the private sector, in the style of Margaret Thatcher’s Britain. Ridley has an occasional tendency to offer glib generalizations about complex issues, and this tendency is particularly apparent in his final chapter. For example, many of the world’s most pressing environmental problems, such as global warming and ozone-shield depletion, call for international solutions, not local ones. Ridley does not distinguish between these rather disparate ecological problems or show clearly just when private solutions are preferable to those involving government action.


Contrasting Sociobiological Faces

Sociobiology has two faces,” the philosopher of science Philip Kitcher asserted a decade ago in his critical review of the field. “One looks toward the social behavior of nonhuman animals. The eyes are carefully focused, the lips pursed judiciously. Utterances are made only with caution. The other face is almost hidden behind a megaphone. With great excitement, pronouncements about human nature blare forth.”12 Which face does Matt Ridley show us in The Origins of Virtue? The answer to this question depends, in part, on which chapter of his book we are considering. One of Ridley’s distinct merits as a scholar is that he understands the difference between speculation and science; he almost always identifies which is which, and also asks whether scientific claims have been adequately tested. Still, my overall impression is that Ridley did somewhat better in The Red Queen in acknowledging points of uncertainty and in stressing rival interpretations of data, probably because more is known about the biology of sex than about human social behavior, which inevitably requires us to unravel the complex interplay of genetic predispositions and historically contingent experiences.

From reading Ridley’s new book, it is nevertheless clear that evolutionary approaches to human behavior have made impressive empirical headway during the last twenty years. As Ridley’s sweeping survey demonstrates, this research program now represents a highly interdisciplinary effort that unites evolutionary biology, behavioral genetics, neurobiology, anthropology, medicine, economics, game theory, psychology, and history—to mention only the most important of the contributing disciplines. It is perhaps no accident that science journalists such as Ridley have become almost indispensable in keeping scientists themselves abreast of this sprawling enterprise. 13 In addition, this rich interdisciplinary approach has created far greater opportunities for establishing truth by empirical convergence.

One last point is worth making in connection with Ridley’s thoughtful and provoking book, and especially with regard to ongoing controversies over the Darwinian perspectives it advocates. In this often heated debate, it does not really help for adversaries to argue about whether human behavior is genetically or culturally determined (it is both); about whether human consciousness invalidates the effects of natural selection (consciousness is natural selection’s most remarkable product, not its antithesis); about whether Darwinian theory robs us of our free will (it clearly does not); or about whether Darwinians can be usefully divided into narrow-minded “ultras,” who attribute everything to natural selection, and open-minded “pluralists” (they cannot be so divided). Critical empiricism, not debating skills on either side, will ultimately resolve these controversies. As Charles Darwin taught us more than a century ago, openness to diverse lines of evidence and a dogged dedication to hypothesis testing are the enduring Darwinian virtues.

  1. 8

    Antonio R. Damasio, Descartes’s Error: Emotion, Reason, and the Human Brain (Putnam, 1994).

  2. 9

    Leda Cosmides and John Tooby, “Cognitive Adaptations for Social Exchange,” in Jerome Barkow, Leda Cosmides, and John Tooby, editors, The Adapted Mind: Evolutionary Psychology and the Generation of Culture (Oxford University Press, 1992), pp. 163-228.

  3. 10

    On genetic propensities toward altruism, see note 5. A fourth line of evidence—studies of child development—is likely to prove important in future research on altruistic behavior (and other Darwinian strategies). If nature and nurture work together in determining our propensity to cooperate, then accurate knowledge of the interactions between developmental mechanisms and contingent experiences, such as those responsible for attachment behavior toward parents and siblings, is essential to understanding the course of individual lives.

  4. 11

    The role of group loyalties in human behavior raises the question of whether selection at the level of the group is capable of promoting altruism, as Darwin believed. Like most modern evolutionary biologists, Ridley rejects this idea because it conflicts with the current Darwinian emphasis on genetic self-interest. In an important book to be published in May, Elliott Sober and David Sloan Wilson have breathed new life into the theory of group selection. They argue that altruism can arise in groups even when there are high costs to the individual, as long as selection at the level of the group is stronger than that taking place at the level of the individual. Throughout human history, warring human factions would have experienced these kinds of multilevel selection pressures. Unto Others: The Evolution and Psychology of Unselfish Behavior (Harvard University Press, 1998).

  5. 12

    Philip Kitcher, Vaulting Ambition: Sociobiology and the Quest for Human Nature (MIT Press, 1985), p. 435. In addition, see Stephen Jay Gould’s critical remarks about evolutionary psychology in “Evolution: The Pleasures of Pluralism,” The New York Review, June 26, 1977, pp. 47-52. Although Gould finds fault with what he sees as evolutionary psychologists’ “ultra” dependence on the mechanism of natural selection, he welcomes a number of conceptual innovations by these investigators.

  6. 13

    Another science journalist, Robert Wright, has recently provided a highly readable introduction to evolutionary psychology with his book The Moral Animal: Evolutionary Psychology and Everyday Life (Vintage, 1994).

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