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The Rise of the Humans

December 15, 2012

A review of The Social Conquest of Earth by Edward O. Wilson.

Edward O. Wilson is one of the grand distinguished scientists of our time, the winner of two Pulitzer Prizes (for On Human Nature in 1979 and The Ants in 1991) who writes intricate and detailed technical papers and books on the most narrow of topics (e.g., ant ecology) in between penning grand theoretical works about human nature, history, and the environment. He has been mistrusted by conservatives for his promotion of the teaching of evolutionary theory and his conservation efforts to preserve the environment, and he has been vilified by liberals for suggesting that humans have a biological nature that is not infinitely malleable by social engineering. His 1998 book Consilience: The Unity of Knowledge was nothing short of a clarion call to resurrect the Enlightenment and reengineer it for the new millennium, suggesting that theologians and philosophers have had their day in the court of morality and ethics and that it is high time scientists had a say in what constitutes right and wrong and the good life. Anything that E. O. Wilson writes about is well worth reading, and The Social Conquest of Earth is no exception.

Readers who are already familiar with “big science” works by such authors as Jared Diamond, Matt Ridley, Robert Wright, Richard Dawkins, and Steven Pinker, covering everything from evolutionary theory through the evolutionary psychology of economics, politics, and morality, will find much of this same well-worn ground reviewed in The Social Conquest of Earth, but with Wilson’s unique perspective as a biologist who studies sociality and the evolution of social species. As such, The Social Conquest of Earth flips back and forth between human evolution and social history and insect evolution and sociality. What is new—or at least different from the other grand works produced by the authors noted above—is Wilson’s endorsement of a controversial idea in evolutionary theory called group selection, in which social groups are the target of natural selection, not just individuals. He describes the process by which groups become cooperative as “eusociality,” or good social groupness, which Wilson contends enables them to compete more successfully against other less-cooperative groups.

Group selection is part of a larger schema called multi-level selection, most prominently promoted by the late Harvard paleontologist Stephen Jay Gould in his magnum opus The Structure of Evolutionary Theory. Gould was one of those liberals who took Wilson to task for his suggestion in the final chapter of his 1976 book Sociobiology that human culture may be in part a product of evolution. Gould and his Harvard colleague Richard Lewontin even formed a group with the Marxist name “Science for the People,” and they launched a series of public campaigns to discredit Wilson. It is with double irony, then, that Wilson won that debate but now fully embraces Gould’s multiselection theory and posits group selection as the driving force behind what makes humans so unique among the primates.

Wilson is not alone. Evolutionary theorist David Sloane Wilson has been pushing this line of thinking for two decades now (see, for example, his 2002 book Darwin’s Cathedral), and even some scientists outside the field are getting in on the action—for example, Jonathan Haidt’s new book, The Righteous Mind: Why Good People Are Divided by Politics and Religion (Pantheon), argues that religion and politics “bind and blind” people in social groups: binding them together so cohesively that natural selection targeted them as groups (instead of individuals) competing against other groups, and therefore blinds individuals to understanding the perspective of people in other groups. Although both authors plead their case well before the judges at the high table of evolutionary theory, having the backing of E. O. Wilson for group selection is something of a milestone in this long-running and contentious debate.

The problem with group selection has always been what is known as the “free rider problem.” If a group consists mostly of cooperative altruistic pro-social individuals who are willing to sacrifice themselves for the group, free riders have the opportunity to exploit their fellow group members by, say, taking a little more food for themselves, or stealing a copulation with someone else’s mate when he’s off on the hunt, and as such the free rider leaves behind more offspring and the genes for free riding are propagated into the future thereby causing the once social group to dissolve into a loose confederation of solitary, poor, nasty, brutish, and selfish individuals. Wilson’s solution is to make the case that the group is not just a collection of individuals but more like a superorganism. Admitting that it is still “subject to experimental verification, Wilson suggests that these eusocial groups evolved as a result there being certain preadaptive genetic traits that lead them to be tightly formed, initially for such practical problems as guarding nests and feeding grounds from other invading groups, and that families and extended families form the basis for these early groups. As these eusocial groups grow in size and strength, other non-relations find it to their individual benefit to support the group as a whole, and as such pro-social behaviors are selected for within the group by individual selection, making these eusocial groups more competitive against other groups, and it is here where group selection may work it’s magic.

In his multi-level selection model Wilson writes (p. 289): “At the higher level of the two relevant levels of biological organization,” by which he means individuals and groups, that “groups compete with groups, favoring cooperative social traits among members of the same group. At the lower level, members of the same group compete with one another in a manner that leads to self-serving behavior. The opposition between the two levels of natural selection has resulted in a chimeric genotype in each person. It renders each of us part saint and part sinner.”

Further, Wilson claims (p. 143) that the selfish-gene model of the development of altruism and pro-sociality was the accepted dogma until he, Martin Nowak, and Corina Tarnita “demonstrated that inclusive-fitness theory, often called kin selection theory, is both mathematically and biologically incorrect.” Kin selection theory holds that we personally benefit from helping our kin and kind because we are genetically related to one another, and thus even though I may sacrifice resources for my genetic relations, from my gene’s point of view this is still an act of selfishness because my genes are propagated through my relations, even if I personally lose resources. Unfortunately, Wilson does not include the mathematical demonstration of this fact in his book, leaving it to readers to judge for themselves by reading the original paper and the critics of it. Most notably, Richard Dawkins has for decades railed against group selection, making an equally sound case (in my opinion) that natural selection operating on individual organisms alone suffices to explain eusociality, cooperation, and morality.

There’s no doubt that having the backing of E. O. Wilson for group selection is something of a milestone in this long-running and contentious debate. My take on this great debate is that it depends on how one defines a group and its cohesiveness. I argued in The Science of Good and Evil that morality (and eusociality, cooperation, and altruism) can evolve as a result of individuals becoming ever more social and their groups ever more cohesive without having to posit the group itself as a “superorganism.” Yes, humans are tribal, but we are very different still than social insects, and certainly drastically different from, say, our own bodies that are superorganisms of independent but coordinated cells and tissues and organs. And it seems to me that good old natural selection operating on individual humans alone (and not the group as a whole) still suffices to account for human social life.

Still, don’t take my word for it. Read the words of the master biologist himself in this marvelous book that, in my opinion, would be just as strong an argument for explaining the rise of the humans without jumping into the controversial topic of group selection.

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