In 2012, at the age of 82, Pulitzer Prize-winning Harvard biologist Edward O. Wilson, the pioneering architect of “sociobiology,” published The Social Conquest of Earth
, an extended strike against established thinking on social evolution. Having devoted much of his career to reconciling social behavior with evolutionary theory, in 2010 Wilson abandoned the widely accepted “kin selection theory” in favor of an alternative, “group selection.” This amounted to something like heresy within the evolutionary biology community. Nevertheless, this 2012 book boldly claims to finally disclose the truth about human nature. Invoking the title of a masterpiece by Paul Gaugin, Wilson aspires to resolve the questions: Where do we come from? What are we? We are we going?
Wilson is considered a leading expert on ants, and his vast knowledge of insect behaviors, especially social behaviors, informs his explanations of human cooperative and altruistic impulses. Both ants and humans are, in Wilson’s words, “eusocial animals,” meaning they work cooperatively to build complex societies which depend on divisions of labor and acts of altruism by individuals. Among the many examples Wilson cites of eusocial ant behavior is that of the leafcutter ant. These insects cut pieces of plant matter, carry them back to their nest and chew them into mulch, which they then fertilize with their waste. This compost supports the growth of a unique fungus that serves as the ants’ principal diet. Moreover, “their gardening is organized as an assembly line, with the material passed from one specialized caste to the next.”
Eusociality is rare, practiced by only about two dozen species, but, Wilson says, these are “the most successful species in the history of life.” The success of humankind speaks for itself, but ants’ domination is impressive as well: “the mass of ants [on Earth] exceeds that of all other insects combined.” Wilson tackles the question of why a few species evolved to become eusocial, while most did not. To do so, he debunks the accepted explanation for social behavior in animal communities known as “kin selection theory.”
Popularized by William Hamilton in the 1960s, kin selection theory extends Darwin’s theory of the natural selection of competitive traits to include altruistic behaviors between close family members. Specifically, the process of natural selection may favor genes that produce behaviors costly to an individual if the cost is outweighed by resulting benefits to family members. For example, a worker bee surrenders her reproductive capability, which is individually costly, but this benefits her mother, the queen bee. Thus, altruism promotes the survival of family genes, and one would expect altruism to increase with relatedness. Wilson once supported this theory, but now scorns it as unable to account for eusocial behavior. He argues that clonal species, whose members are highly related, are not predominantly eusocial, and species such as termites and shrimp, who are eusocial, do not share an unusually high degree of genetic similarity between kin.
Having scuttled the establishment model, Wilson makes his case for multilevel natural selection, or a model of evolution that allows for the selection of genes that are beneficial at either the individual or group level. Individual selection works to give individuals a competitive edge over others in passing along their own genes, and is always in tension with group selection, which favors genes that give a group advantages over competing groups. Moreover, group members are not necessarily related, or “kin.” They cooperate with one another not to propagate familial genes, but because natural circumstances trigger latent altruistic tendencies that will help the group survive. This can lead to full-blown eusociality, but only rarely because, as Wilson explains, “groups selection must be exceptionally powerful to relax the grip of individual selection.”
Only a small number of species are genetically predisposed to eusocial behavior, which, according to Wilson, then only develops following a critical pre-adaptive step: nest-building. Populations that once roamed settle after building nests. Conditions are favorable for eusociality when young remain in the nest, as this encourages divisions of labor: some members of the group will gather food, while others defend the nest. The human equivalent of nest-building is the campsite. With the advent of stable groups of humans living together at persisting sites, the genetic evolution of traits beneficial to the group, like altruism, occurs. Thus, humans crossed the threshold into eusociality.
Having dispatched the question, “where do we come from,” Wilson addresses the next one, “what are we?” Conflicted, is the answer in a nutshell. Human nature, the book posits, arises from an evolutionary process that genetically hardwires people to be both selfish (a trait favored by individual selection) and altruistic (a group selection trait). In human society, the virtues of honor, duty and self-sacrifice are always battling counter impulses toward selfishness and cowardice, and from this crucible of opposing forces comes culture itself. Language, art, religion and more result from the conflict that structures multilevel natural selection, which Wilson calls “the fountainhead of the humanities.” This claim underpins the books short chapters on the origins of language, morality, religion and the creative arts.
“Gene-culture coevolution” is Wilson’s term for how cultural practices emerge and continue due to the “genetic predisposition of individuals to select and transmit through culture one out of multiple options possible.” Understanding that organized religion, which foster tribalism, is just a cultural artifact of gene-culture coevolution may discourage moral judgements based “blindly on religious and ideological dogmas.” Moreover, if genes determine tribalist and racist behaviors, they also drive altruism and coalition-building. Considering the question “where are we going?” in his final chapter, Wilson is optimistic that, through science, people will discover how to enhance their “virtuous” genetic inheritance. This will benefit not just people, but the whole planet.
Many well-respected evolutionary biologists have rebuked Wilson’s theories with counter-arguments supporting the “kin selection theory” of social evolution. One eminent researcher, Jerry A. Coyne, dismissed Wilson’s group selection ideas as “dreck.” But in an interview published in The Atlantic
, Wilson shrugged off criticism with confidence: “I don’t care […] because I feel so secure about the theory and interpretation.”