David Sloan Wilson’s essay Human Cultures are Primarily Adaptive at the Group Level is helpful in calling attention to the fundamental role that the human social group has played throughout our evolutionary history. But Sloan Wilson is mistaken, in my view, in seeming to use the phrase “primarily adaptive at the group level” to mean that humans have acquired a suite of social and psychological dispositions for promoting the fitness of their groups even if it means suffering a cost to their own fitness.

There is agreement that there is something important to explain. Human beings are distinguished among all animals for having forms of cooperation that, on the face of it, pose a challenge to conventional Darwinian accounts of evolution. We routinely help others, we share our knowledge and skills, we give up seats on trains, pay taxes, hold doors for people, give money to charities, and even sometimes risk our health and well-being to fight wars.

The challenge to Darwinism is to explain how such apparent altruism can evolve when there are people who are only too happy to benefit from your aid but have no intention of returning it. This question is often answered by drawing on an analogy to the social insects – the ants, bees, wasps and termites – or even to the skin cells in your body.

Individual ants quite willingly, indeed sometimes enthusiastically, go to their deaths in support of their queen, and skin cells in your body do not have to be coaxed into giving their lives to protect you from the harmful rays of the sun. These actors’ high genetic relatedness to each other makes selfless altruism a good strategy for promoting copies of their genes that reside in others.

But humans are different – the multiple actors in the great ‘bodies’ we call our societies are not like cells in a body, nor even like a colony of ants. Indeed, the wonder of human cooperation is that we somehow manage to make our style of altruism work even among non-relatives. We have moved beyond the mere eusociality of the social insects to a ultrasociality, this term acknowledging that we cannot explain our actions as strategies for promoting copies of our genes in relatives.

Sloan Wilson is one of the leading proponents of ‘group selection’ as a way to explain this fascinating dilemma of human behaviour. The idea is that our groups have been as important to our survival and well-being throughout our evolutionary history as an ant’s colony has been to it. As a consequence we have been moulded by natural selection to do things that advance our ‘colonies’ even if it means suffering a cost to our individual fitness.

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