Martin Nowak and Roger Highfield’s “SuperCooperators”

Martin Nowak has accomplished a lot for a mid-career scientist. His theoretical work exploring how cooperation evolves has illuminated the importance of a great number of evolutionary mechanisms. He has also been unafraid to tackle real-life problems of cooperation, including questions like “why do we get cancer?” and “how did language evolve?”. Nowak likes to propose radical ideas and seed controversy, as his recent publication (“The evolution of eusociality”) with Corina Tarnita and Edward O. Wilson suggests (Nowak et al. 2010). It was high time that Nowak synthesized his diverse work on the evolution of cooperation. This overdue synthesis comes in the form of SuperCooperators, a book co-written with Roger Highfield.

I appreciate Nowak’s attempts to create meaningful conceptual frameworks that help explain the inter-relationships between different evolutionary mechanisms. If you read the evolutionary theory literature — in particular that literature dedicated to explaining how cooperation evolves — it often comes off as a scattered, incoherent collection of little explorations. Nowak clearly seeks to understand how these small-scale explorations can be used to create theory that explains the larger phenomenon of cooperation; this is an admirable goal.

SuperCooperators starts off by making sure that the reader understands the great importance of cooperation. Its preface rightly takes to task the assumption that human innovation is founded on competition, conjuring a series of images and ideas that make it clear that we rely on our fellow human beings in order to survive on a daily basis. It then moves on to Nowak’s favorite game: the prisoner’s dilemma. Cleverly the book has a “Chapter 0”, which provides a conceptually-clear description of how the prisoner’s dilemma works. Chapters 1 through 5 then moves through Nowak’s “five mechanisms for the evolution of cooperation” (Nowak 2006), all of which revolve around explorations of the prisoner’s dilemma game under a variety of complicating assumptions.

In his section on kin selection, Nowak expands upon the more narrow argument made in the “evolution of eusociality” paper. This makes for interesting reading because Nowak simultaneously honors the historical significance of kin selection in his pantheon of evolutionary mechanisms and then suggests that the value of kin selection as a theory is waning. One should notice that Nowak prefers the term “kin selection” over “inclusive fitness” (although he employs both terms), and I would venture to say that this is a notable choice: much of the argument over kin versus group selection comes down to what you define as “inclusive” to the fitness of individuals in a population. The historical component of this chapter is really valuable, walking the reader through the important contributions of J.B.S. Haldane, John Maynard Smith, William D. Hamilton, and George Price. I also found the second half of the chapter to be valuable, if for no other reason because it clearly lays out his argument against inclusive fitness theory. Nowak explains the very different approach that kin selection requires theorists to take and briefly explains some of the problems with this approach. Readers interested in the issue will have to pursue further readings, but SuperCooperators lays out the basic argument.

My favorite portion of this book is the middle “Feats of Cooperation” section, which encompasses three chapters dedicated to the origins of life, multicellularity, and eusociality. These chapters provide easy-to-understand overviews of Nowak’s work on RNA hypercycles, cancer, and superorganisms. Readers struggling to figure out why all the theoretical work introduced in the first six chapters matter are most likely to be convinced by the “Feats of Cooperation” section, as it nicely highlights Nowak’s attempts to bridge esoteric theory over to real-life problems. The following section, “From Cooperators to SuperCooperators”, also gets off to a nice start by illuminating Nowak’s work on language evolution. There is also a great chapter on public goods, and three interesting if not a-little-too-focused-on-Nowak chapters on the role of punishment in cooperation and on social network theory. The final chapter, “Crescendo of Cooperation”, finally takes the train off the rails (as I will describe below).

This book is certainly worth reading. There are a lot of insightful points and valuable conceptual clarifications made here. For example, in discussing the iterated prisoner’s dilemma game, Nowak points out that different player strategies require very different cognitive capacities: playing “tit-for-tat” requires that a player recognize and respond to an opponent’s move, whereas the alternative strategy “pavlov” only requires an understanding of one’s own recent success or failure. A similar argument is made about inclusive fitness theory: true kin selection cannot occur unless an organism has the ability to resist being exploited by recognizing kinship. These related points share the common idea that models must consider what suite of capabilities are available to organisms: deciding that a given model represents the behaviors of a given organism has to include a consideration of what that organism is capable of doing.

As a theoretician I also learned a lot from Nowak’s approach to modeling, even if SuperCooperators omits all the technical details. One frequent technique that Nowak employs is to start off investigations with simulations of cooperative behavior. This allows him to establish patterns of possible outcomes and then reverse-engineer the mathematics that predict these patterns. While such an approach does not remove all obstacles — one can still make an over-simplified model from overly-simple simulation assumptions — it seems to me that this approach is more likely to be fruitful than the conventional approach, which is to assume that one knows the right equations and then retreat to simulations only when the math becomes intractable. Real organisms are more like individuals in a simulation than they are like the mathematical equations we hope to write describing their aggregated behavior, so starting with sims is an approach that more theoreticians should consider.

In a page out of one of David Sloan Wilson‘s books, Nowak also devotes large swaths of SuperCooperators to profiling prominent scientists. Nowak is a bit more selective than Wilson in who he profiles, but he is equally effective at bringing to life the character, genius, and complexity of the people he describes. An especially good profile is provided for Garrett Hardin, who brought the idea of “The Tragedy of the Commons” into the public spotlight, as Nowak describes Hardin’s struggle with the very touchy question of whether people should be free to have as many children as they please. It is interesting to me that the two scientists who advocate the oft-maligned idea of group selection most vehemently also share this approach to writing: are they more aware of the varied and valuable contributions of others because they think about evolution at levels above the individual?

I also really appreciate the many provocations this book provides. Nowak is unapologetic in his rejection of the Price Equation as a valuable tool for understanding the evolution of cooperation. He absolutely rips apart gene-centered theory on numerous occasions, my favorite of which involves RNA quasispecies. Nowak explains that in the evolution of prelife via spontaneous RNA replication, one cannot strictly view a particular RNA strand as competing against strands differentiated by slight variations: because back-mutation can occur, closely-related strands are actually cooperating in a semi-coherent “group”. Not every provocation provided in SuperCooperators was convincing: I still do not see the need to invoke group selection to explain the evolution of multicellularity, and Nowak completely loses me when he imagines that our origin might be the result of extraterrestrial seeding. But taken as a whole, many of Nowak’s provocative off-the-beaten-path views are refreshing and necessary to the continued development of valuable evolutionary theory.

Although this book tries to bring mathematically-complex ideas to the lay reader, it only occasionally does so with any real success. The book is all words, eschewing the use of images that might help the reader understand key model concepts. Comically, the book’s most frequently-used strategy for not scaring the math-phobic is to convert equations and inequalities into words: if the symbols are removed, does the math get easier? I do understand the challenge at hand — making fairly ornate mathematical maneuvers meaningful to the mathematically-uninitiated — but if the goal was to impart readers with a clear sense of what Nowak’s famous mathematical skills have yielded in terms of scientific insights, this book falls well short of that goal.

If you have a hard time reading the unselfconscious reflections of the privileged elite, you may have difficulty getting through this book. Nowak seems remarkably shameless about discussing his own enchanted life, one that takes him from one bastion of intellectual privilege to another. From what I know of his accomplishments, he has earned every single one of these choice appointments (although one cannot help but notice the snowballing effect of bouncing from one grand old university to the next), and Nowak is generous with his praise and acknowledgement of the people with whom he has cooperated. But for whatever reason the narrative is also unfailingly about Nowak and his rather self-focused perspective. I, for one, set out to read a book that would better help me understand how cooperation evolves; every aspect of this book which serves as self-celebratory memoir seems to be a distraction from this key objective and, frankly, a bit premature. The persona Nowak betrays in this book is ironic given what he studies.

Perhaps the persona presented in the book is not Nowak’s true persona. The book was written with Roger Highfield, a science journalist, writer, and broadcaster, so it is hard to tell which of the two actual authors of this book is most responsible for its haughty voice. I was excited to hear Nowak’s voice and I doubt that this is completely it: listening to any one of Nowak’s many online lectures is a very different experience than reading this book. The up side of Nowak’s choice to collaborate with Highfield is that this is a very well-written book. The downside is that it comes off as almost too polished and promotional, too reader-friendly, to the point of feeling like the author is condescending to the reader. Although the book is clearly aimed at a lay reader, it sometimes overdoes that appeal.

Nowak is fond of telling a joke about a mathematical biologist who can accurately quantify the number of sheep in a herd but who mistakes the shepherd’s dog for a sheep (he tells the joke here if you want to hear it in its entirety). Sometimes I wonder if he fully gets this joke. The punchline suggests that mathematical depictions of biology work well at solving only the narrow problem at which they are aimed. That Nowak tells this self-deprecating joke might lead one to believe that he was expressing humility, acknowledging the limits of his field, but it appears his reason for telling the joke has nothing to do with humility (a la Greengross and Miller 2008). Time and again we see mathematical biology lionized in ways it simply does not deserve, especially given that Nowak usually ends up relying on a lot of computer simulations to deal with complexity that the math cannot handle. Reading SuperCooperators, one would think that all that is needed to create a smooth-running cooperative society is a thorough mathematical analysis of the prisoner’s dilemma. While I agree that the prisoner’s dilemma is a valuable heuristic, especially when complicated with more realistic assumptions (as Nowak has done admirably), it is far from being ready to explain the complexities of human cooperation. At points in SuperCooperators, Nowak practically claims to have discovered the equations for criminality and the latest economic crisis. And it is not just humans who get the mathematical work-up: Nowak suggests, based on the fact that there has been limited success at creating synthetic life through genetic manipulations, that all organisms are best viewed as “information-processing systems”. In lauding Stephen Wolfram’s work, Nowak also suggests that the universe itself is simply “the outcome of cellular automata”. My reaction to all this mathematical bluster is to say “call me when this is stuff is ready to be used for something practical”. Under many circumstances, being able to tell a sheep from a dog is far more important than getting an exact count of that herd.

For all of its other shortcomings, perhaps the most annoying facet of this book is its tendency to make wild unfounded extrapolations from Nowak’s valuable modeling work into the real world. I have no problem with modelers who say something akin to “my model might help explain the real-world phenomenon of [blank], which shares some of the real-world assumptions of the model”, but Nowak is fond of suggesting that his models unequivocally do explain how cooperation functions in complex human societies. Anyone who has read the famous Nature paper “The evolution of eusociality” (Nowak et al. 2010) will already be familiar with Nowak’s unwarranted comfort with declaring that he has discovered the equation explaining large swaths of nature. But this tendency gets really wild at the end of SuperCooperators, where we are assured without explanation that Nowak’s “five mechanisms for the evolution of cooperation” are ready in present form to help us engineer a more cooperative future. To me Nowak’s view of human cooperation seems rather cartoonish, overly-optimistic, and naive: he fails to acknowledge that much of the cooperation we see in present-day human societies is coerced. There is no mention of the widespread top-down aggregated defection that is manifested in various forms of totalitarianism and economic exploitation. In fact, in several places Nowak suggests that punishment by individuals is problematic but punishment meted out by higher authorities may be necessary, which to me is further evidence that he has not yet thought all that rigorously about the real multilevel selection involved in contemporary human societies. We are told that “cooperation has to come from the bottom up”, but how and why this is true is never explained. When Nowak’s equations can explain how it is that the richest people on the planet work the least, his scientific conceit will be justified. Until that time it would be more honest if we in the business of studying the evolution of cooperation would be more humble about our accomplishments: it is a noble pursuit, but we have a lot of work to do before we can explain the many tensions in human society between cooperation and defection.