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

Review of Martin Nowak,

SuperCooperators:

Free Press (2011)

Herbert Gintis

Martin Nowak is a mathematician and scientist of great stature, expansive ambition, and all-embracing energy. He avoids being hog-tied to any particular discipline, but rather follows his fancy where it takes him in the behavioral sciences. Nowak is especially admirable because he is an iconoclast who comes out guns a-blazing to confront any Received Wisdom with which he fundamentally (or even marginally) disagrees. He apparently does not mind being wrong (he sometimes is) because when he is right, it more than makes up for his goof-ups. Nowak was a student of Peter Schuster, the great mathematical chemist, and a student and coauthor of the biological mathematician Karl Sigmund, at the University of Vienna in the late 1980's.

Nowak is currently the head of the Program for Evolutionary Dynamics at Harvard University. He was hired by Harvard after an admirer offer to contribute a Very Large Sum to the Harvard endowment as part of a deal to install him as Professor of Mathematics and Biology at the august institution. Nowak steps on lots of peoples toes, and there is little chance he would have been hired at the venerable school without the huge monetary emolument. This is no criticism of Nowak---Harvard does not cotton up to anti-Establishment, transdisciplinary, iconoclastic intellectuals. To round out Nowak's multidimensional cerebral life, he is an observant and pious Catholic, and his work at Harvard is co-sponsored by the Templeton Foundation, famous for its support of projects that link science and spirituality.

The main theme of SuperCooperators is both important and ubiquitous in modern behavioral science: we humans are who we are because we evolved that way biologically, and cooperation has been the key to our success as a species. "Out breathtaking ability to cooperate is one of the main reasons we have managed to survive in every ecosystem on Earth, from scorch, sun-baked deserts to the frozen wastes of Antarctica to the dark, crushing ocean depths" (the hyperbole is a typical of Nowak's literary tricks; in fact we have not survived in any of the three ecosystems he mentions, but we have in most of those he does not). If the last half of the Twentieth century was the Homage to Selfishness, the first half of the current century is the Homage to Cooperation. Perhaps the most important contribution to this new theme is John Maynard Smith and Eors Szathmary's The Origins of Life, which depicts each stage in the development of biological complexity as the synergistic synthesis of hitherto competing biological entities, from single-cell to multicellular organisms, from prokaryotic to eukaryotic cells, all the way up to social species, of which our species is among the most successful. As for humans, Samuel Bowles and I have argued this position for some fifteen years, our book "A Cooperative Species" (Princeton, 2011) coming out in a few months, and our colleagues Robert Boyd and Peter Richerson predated our effort by at least a decade.

SuperCooperators is extremely accessible to non-scientists. It dispenses with footnotes and highly accurate but complex phraseology, in favor of explaining concepts in a witty, conversational, and light-handed manner. One is struck throughout with Nowak's love of mathematics and science. He repeatedly conveys to the reader his the love of knowledge for its own sake (he regularly quotes from Albert Einstein, a man whose passion for truth approached theological levels). He also conveys his commitment to and fondness for his co-researchers, both teachers and mentors (the book is dedicated to Bob and Karl---presumably his mentor Robert May and his teacher and coauthor Karl Sigmund). In fact, SuperCooperators is much more a book about the work of Nowak and his Harvard Program for Evolutionary Dynamics than it is an even-handed overview of the field and its development. This was a good choice on Nowak's part, because it permits him to convey the degree of collegiality and personal commitment that is one of the great comforts of scientific research, and is often ignored in favor of maintaining the emotional flatness that is (falsely) reputed to be the hallmark of good science.

How do we account for human cooperation? Nowak offers five very broad mechanisms: direct reciprocity, indirect reciprocity, spatial selection, multilevel selection, and kin-selection. He devotes a chapter to each of these mechanisms, in each case highlighting his own contributions. This may sound self-aggrandizing, and it is. But I do not think this is a mistake. The benefit for readers is a sense of intimacy with the writer, who becomes the protagonist in a scientific melodrama, a knight in shining armor slaying falsity and promoting truth wherever his wanderings take him. However, this approach does not allow the reader to appreciate the substantive scientific issues involved. For instance, Nowak is strong supporter of kin-selection, but a bitter critic, along with Harvard colleague Edward O. Wilson and co-worker Corita Tarnita, of William Hamilton's explanation of kin-selection in terms of "inclusive fitness." Now you must understand, dear reader, that the inclusive fitness concept has become the standard explanation of cooperation in population biology and animal behavior theory, so Nowak's critique, presented in Nature in 2010, produced a major shake-up in the profession. Nowak presents his critique here, but does not attempt to relate the counterarguments, which are at least extremely interesting, and probably indicate serious problems with the Nowak-Tarnita-Wilson argument. For one think, the authors pose inclusive fitness theory as an "alternative to natural selection," which is pretty ludicrous. Right or wrong, inclusive fitness theory is a form of natural selection, not an alternative to natural selection.

To convey his light-handed treatment of scientific themes, consider Nowak's treatment of multilevel selection. After two short paragraphs going over the history of group selection (focus on Wynne-Edwards' latter years studying red grouse with binoculars from the window of a room in a rest home in the Dee Valley), Nowak confesses that earlier attempts to model multilevel selection were "too complicated for my taste" and that he and Karl Sigmund did not find them "particularly convincing." This manner of presenting objections to a scientific theory bypasses all substantive issues (what were the earlier models and what were their successes and deficiencies) and moves directly to the subjective emotions of Nowak and Sigmund. How does Nowak describe his and Sigmund's passage into the theory of multilevel selection. "In the heart of the Rauriser Urwald," he writes, "Karl [Sigmund] and I came across a little wooden board bearing a poem by Goethe (1749-1832)...Goethe's poem begins as follows: "Müsset beim Naturbetrachten immer eins wie alles acten." This translates as "When looking at nature, you must always consider the detail and the whole." I could not think of a better way to express the idea of multilevel selection and, though I realized the field had a long, troubled, and vexatious history, I began to think about whether it might work in the real world." Now, of course, the Goethe quote can be interpreted in many ways, but none of them has anything to do with multilevel or any other form of selection. Moreover, I frankly do not believe that this story is accurate. It sounds like an apocryphal yarn, like the one about Newton and the apple.

Nowak goes on to explain the model of multilevel selection with Arne Traulsen that is no different than a dozen previous models of the within-group cost and between-group benefit of altruistic behavior, and with no mention of Price's equation, which was the inspiration for all previous mathematical models of multilevel selection (Nowak belittles Price's equation later in the book as being "tautological", which is incorrect, as it depends on a empirically meaningful analytical representation of biological fitness). The paper Traulsen and Nowak wrote (PNAS 2006) was indeed simple and elegant, but hardly earthshaking. The elegance derives from its simplifying assumptions (recall Nowak's distaste of complexity), which include (a) no migration; (b) fixed maximum group size; (c) groups of maximum size consist of all cooperators or all defectors. None of these conditions is biologically relevant, so the Nowak Traulsen contribution is likely only of passing interest. To reiterate, I do not consider Nowak's self-aggrandizement a mistake, given his goal of presenting the non-scientist reader with a highly human treatment of behavioral and mathematical theory. The historians will sort out who actually did what, and the average reader does not really care at all. However, this approach does lead to the suppression of scientific content in favor of personal feelings and memorable anecdotes.

Given his strong personal commitments to his co-workers, it is not surprising that Nowak rarely has praise for the sustained and seminal contributions of contemporary researchers who work outside his research group. Luca Cavalli-Sforza, Robert Boyd, Peter Richerson, Robin Dunbar, Alan Grafen, Amos Zahavi, and Joseph Henrich are not mentioned at all, and others, including Samuel Bowles and Marcus Feldman, are mentioned in passing for a particular study or two, but nothing revealing the depth of their thought or nature of their contributions to modern behavioral science. Similarly, he has little room for contributions from other fields, such as economics, sociology, and psychology, or evidence from archeology, history, anthropology, or paleontology. This I also consider a shortcoming. Weaving the contributions of others with his own in a more substantive way would give the reader a better appreciation for the contemporary state of research on cooperation and conflict in the animal and human world. Perhaps this is just tit-for-tat, as I find that few authors from the behavioral sciences outside of Nowak's circle pay much attention to the work of Nowak and his students. My problem with Nowak's models is that they tend to remove important aspects of the subject being modeled in the interest of obtaining elegant formulas. What, for instance, is the value of a model of group selection without migration and variable group size? What, indeed, are we supposed to make of the Prisoner's Dilemma played on a grid, when in real life no species plays any games at all on a grid.

I like the fact that Nowak does not shy from headlong attack on ideas that he thinks are wrong. I am not so happy, however, when the ideas of people with whom I work are being attacked. Nowak's Chapter 12, "Punish and Perish," is just such an attack. In various works, my colleagues and I have proposed that humans exhibit a behavioral syndrome we call "strong reciprocity," according to which most humans have a predisposition to cooperate in collective endeavors that depend on voluntary participation, the success of which depends on a high rate of cooperation and a low rate of defection, and also have a predisposition to punish those who free-ride on the cooperation of others, without requiring that their efforts be repaid in the future. The latter predisposition has been called "altruistic punishment," and it is this concept to which Nowak objects. I think Nowak has correct objections to assertions we do not make but that he attributes to us, and incorrect objection concerning statements we do make.

Nowak begins Chapter 12 by saying that "Punishment is not, as some have claimed, a mechanism for the evolution of cooperation." Rather, he claims, "punishment fits neatly into the framework of the Prisoner's Dilemma." Here Nowak's claim is incorrect. The Prisoner's Dilemma, and direct reciprocity as well, are only relevant in dyadic interactions, and it is quite true that altruistic punishment is irrelevant in such interactions, or in fact in even broader interactions where reputation effects are powerful and ubiquitous. However, human cooperation occurs in large groups in which reputation effects have little or no power. It is these situations that altruistic becomes relevant for sustaining cooperation.

For instance, consider voting in a democratic society. It is costly to vote and because one vote cannot change the outcome of an election except in the smallest of communities, a purely self-regarding person would never vote. Voting is thus mostly an example of the positive side of strong reciprocity, that of altruistic cooperation. However, many people vote because their family, friends, and associates would disapprove of their lack of community spirit if they did not vote. If A does not vote and B expresses disapproval, then B incurs the cost of disrupting the normal relationship between A and B. Disapproving of A is thus an act of costly altruistic punishment, supporting democratic norms at personal expense without the likelihood of any personal gain therefrom. Without such altruistic punishment, voting might be considerably less common than it is, a situation that could delegitimize political democracy.

Consider also ostracism, which is a common group punishment to a member who violates the norms associated with group membership. An individual is ostracized when all (or at least most) group members rupture normal relations with the individual and/or actively prevent the individual from participating in group activities or sharing the benefits of these activities. We tend to ignore the altruistic punishment side of the ostracism phenomenon, but it is always present, unless there is an external third party who has an incentive to enforce the ostracism decision.

Nowak does recognize the existence of mufti-player games, as when he says "If I punish you for defecting in games with other players, that is indirect reciprocity." This statement, however is incorrect. Indirect reciprocity depends on the ability of the group to establish strong reputational information, but such information is generally not available in large groups. If I express to you my disapproval of your not voting who, other than yourself, will see this action and use it to increase my stock of "good reputation"? The answer is generally, no one; nor do I express my disapproval because I hope to gain reputation-wise.

Of course altruistic punishment is not a "mechanism of evolution" in the sense of direct reciprocity, indirect reciprocity, and the others among Nowak's "big five." The big five are social mechanisms, whereas, altruistic punishment is an evolved form of behavior exhibited by humans that contributes to human cooperation, and hence to the emergence of our species as a world-scale key player. It operates in direct interactions, large groups, and explains important aspects of multilevel selection in humans, but like big teeth, wings, or an advanced immune system, it is not a "mechanism" of evolution.

Nowak also stresses that in the many experiments that have shown the efficacy of altruistic punishment in fostering cooperation, in fact the cost of punishing often completely offsets the gains from cooperation. He does not, however, present the important study by GÃÃ,Ã,Â¤chter, Renner and Sefton (2008) in which subjects are allowed to interact over 50 periods rather than just 10. They found that after the initial rounds, the net benefits to the group with the punishment option significantly exceeded those of the no-punishment group with the difference in net payoffs growing over time, except for the final round in which the hapless end-game free-riders were heavily punished.

Given that most social dilemma interactions in neighborhoods, work teams, and the like, extend over far more than 10 periods, the concern that altruistic punishment lowers group benefits to be misplaced. The experiment to which Nowak refers (Dreber et al. 2008) does not constitute evidence for the counterproductive punishment hypothesis for the additional reason that their two-person game made punishment irrelevant, for one could always retaliate on a defector simply by withdrawing cooperation, thus obviating the need for any special kind of punishment. But while the 50-period design of the GÃÃ,Ã,Â¤chter et al. experiment corrects one of the design biases that suggested counterproductive punishment in the earlier experiment, their design still misses something essential to altruistic punishment in the real world: it is effective only if it is regarded as legitimate according to widely held social norms.

Ertan, Page, and Putterman (2009) designed an ingenious experiment to explore this possibility. They allowed experimental subjects prior to playing the public goods game to vote on whether punishment should be allowed and if so, should it be restricted in any manner. From their first opportunity to vote, no group ever allowed punishment of high contributors, most groups eventually voted to allow punishment of low contributors in the baseline treatments, and the result was both high contributions and high efficiency levels. In the laboratory, groups solved their free-rider problems by allowing low contributors alone to be punished. Apparently the determination of the punishment system by majority rule made the punishment not only an incentive but also a signal of group norms.

Nowak also argues that what we call altruistic punishment is often costly but not motivated at all by prosocial feelings of punishing norm violators. Rather it is motivated by spite and a taste for revenge. Punishing those who have hurt you is normally motivated by a taste for retribution rather than a selfless expression of support for public morality. Indeed, in our research we tend to term this costly punishment, and it is altruistic in the sense of being other-regarding. However, fully understand that retribution is generally not motivated by prosocial intentions. Much of the punishment that occurs under the rubric of strong reciprocity is motivated by the urge to retaliate simply because hurting those who hurt you is a selfish, however socially useful, pleasure.