Group Selection Justified by Gene-culture coevolution

Gene-culture coevolution is a modern hypothesis applicable to mostly humans that combines evolutionary biology and modern sociobiology to justify group selection.^[29] It treats culture as a separate evolutionary system that acts in parallel to the usual genetic evolution to transform human traits. It is believed that this approach of combining genetic influence with cultural influence over several generations is not present in the other hypotheses such as reciprocal altruism and kin selection, making gene-culture evolution one of the strongest realistic hypotheses for group selection. Fehr provides evidence of group selection taking place in humans presently with experimentation through logic games such as prisoner’s dilemma, the type of thinking that humans have developed many generations ago.^[30]

Gene-culture coevolution, or cumulative cultural evolution, allows humans to culturally evolve highly distinct adaptations to the local pressures and environments much quicker than with genetic evolution alone. Robert Boyd and Peter J. Richerson, two strong proponents of cultural evolution, postulate that the act of social learning, or learning in a group as done in group selection, allows human populations to accrue information over many generations.^[31] This leads to the cultural evolution of highly adaptive behaviors and technology alongside genetic evolution. Specifically, they believe that the ability to collaborate with each other evolved during the Middle Pleistocene, a million years ago, in response to a rapidly-changing climate.^[32]

Herbert Gintis approaches cultural evolution of group selection in a much more statistical approach to prove that societies that promote pro-social norms, as in group selection, have higher survival rates than societies that do not.^[33] He does so by developing a multilevel gene-culture coevolutionary model that explains the process whereby altruistic social norms will hinder socially harmful and fitness reducing norms and consequently will be internalized. In his equations, he differentiates between a genetic group selection model that is sensitive to group size and migration rates versus his own model that is much less affected by these constraints and therefore more accurate.^[34]

Group Selection due to differing ESSs

The problem with group selection is that for a whole group to get a single trait, it must spread through the whole group first by regular evolution. But, as J. L. Mackie suggested, when there are many different groups, each with a different Evolutionarily Stable Strategy (ESS), there is selection between the different ESSs, since some are worse than others^[35]. For example, a group where altruism arose would outcompete a group where every creature acted in its own interest.