In general, I don’t share Richard Dawkins’s lament that Wilson’s championing of multi-level selection is the result of the sad decline of a once-great scientist.
For one thing, I don’t have Dawkins’s personal stake in kin selection theory. For another, I think that Wilson may be on to something with his proposition that individual selection in humans works through competition between the members of a group, while group selection works through competition between groups. This two-part process is multi-level selection.
Each individual is linked to a network of other group members. Its own survival and reproductive capacity are dependent in part on its interaction with others in the network. Kinship influences the structure of the network, but it is not the key to its evolutionary dynamics, as is wrongly posited by inclusive-fitness theory. Instead, what counts is the hereditary propensity to form the myriad alliances, favors, exchanges of information, and betrayals that make up daily life in the network.
Wilson has long been recognized as the expert on ants and other “eusocial” insects, which live together in altruistic groups of specialized workers. Some of his critics think that he has applied his insights into ants rather too directly to human social groups, but I didn’t get that impression from the book. Indeed, Wilson is careful to distinguish between humans and other social species, including our closest primate relatives. He makes this distinction early, and he keeps returning to it.
There are major differences between humans and the insects even aside from our unique possession of culture, language, and high intelligence.
Prehuman ancestors had to achieve eusociality in a radically different way from the instinct-driven insects. The pathway to eusociality was charted by a contest between selection based on the relative success of individuals within groups versus relative success among groups.
The insects could evolve to eusociality by individual selection in the queen line, generation to generation; the prehumans evolved to eusociality by the interplay of selection at the level of individual selection and at the level of the group.
One of the most engaging ideas in The Social Conquest of Earth is Wilson’s claim that multi-level selection is the engine that drives the duality of human nature. In its simplest form, Wilson’s idea is that the tension we all feel between selfish and generous, aggressive and accepting, “me” and “us,” is the eternal clash between the contrary impulses of the biological products of individual and group selection.
The human condition is an endemic turmoil rooted in the evolution processes that created us. The worst in our nature coexists with the best, and so it will ever be. To scrub it out, if such were possible, would make us less than human.
In taking this view, Wilson explicitly reduces kin selection to a specialized, minor role in human evolution.
The foundations of the general theory of inclusive fitness based on the assumptions of kin selection have crumbled, while evidence for it has grown equivocal at best. The beautiful theory never worked well anyway, and now it has collapsed.
Wilson argues, as he has before, that recent mathematical analyses have undermined the accepted view of the power of kin selection. Wilson is not downplaying natural selection at the individual level, which he writes “has prevailed throughout the history of life.” His claim is that, first, kin selection is not powerful enough to account for human social behaviour and, second, under the right conditions, group selection can “modify the conservative effect of individual selection and introduce highly cooperative behavior into the physiology and behavior of the group members.”
The key question remaining in the dynamics of human genetic evolution is whether natural selection at the group level has been strong enough to overcome the powerful force of natural selection at the level of the individual.
Group selection can prevail if the relative rate of group extinction or diminishment in groups without altruistic genes is very high.
Bands and communities of bands with better combinations of cultural innovations became more productive and better equipped for competition and war. Their rivals either copied them or else were displaced and their territories taken. Thus group selection drove the evolution of culture.
Wilson proposes a simple mechanism for the transformation of individual to group action. All of the actions of the group are versions of those that would be performed by solitary individual in the same environment — “cooperation in expanding, defending and enlarging the nest, obtaining food, and rearing the immature young.” When the instinct for the young to leave the nest and head out to fend for themselves is absent or suppressed, these key survival tasks become group tasks.
Does this process reduce us to the level of the eusocial insects? Wilson doesn’t think so, for the straightforward reason that genes are not human nature. Rather, the behaviours that genes promote are human nature.
Human nature is not the genes underlying it. They prescribe the developmental rules of the brain, sensory system, and behavior that produce human nature. Nor can the universals of culture discovered by anthropologists be defined collectively as human nature.
Human nature is the inherited regularities of mental development common to our species. They are the “epigenetic rules,” which evolved by the interaction of genetic and cultural evolution that occurred over a long period in deep prehistory. These rules are the genetic biases in the way our senses perceive the world, the symbolic coding by which we represent the world, the options we automatically open to ourselves, and the responses we find easiest and most rewarding to make.
Wilson is convinced that understanding biology leads to understanding human nature. His approach is not “reductionist” in any negative sense. Indeed, as he claims, it’s hard to see how any other approach than the biological can lead to any true understanding of the human nature that arises from biology.