For a half million years, evolutionary "survival of the fittest" has applied to both genes and memes.

As villages competed in battle for control of scarce game and water resources, outcomes likely depended as much on group cohesion as on individual physical stamina and prowess. Viewing a human individual's brain as a "wet computer", the genes of the individual determine the capabilities of his "hardware", and the memes, the ideas and world view that the individual acquires from his village, determine the capabilities of his "software". If so, then human evolution is simultaneously a joint evolution of not only genes, but also memes (roles, including gender roles, i.e. ways of life).