From the opening of chapter 5:
I suggested that modern human values initially emerged somewhere around 100,000 years ago (±50,000 years) as a consequence of the biological evolution of our big, fast brains, and that once we had our big, fast brains, cultural evolution became a possibility too. Because of cultural evolution, human values have mutated rapidly in the last twenty thousand years, and the pace of change has accelerated in the last two hundred years.
I identified three major stages in human values, which I linked to foraging, farming, and fossil-fuel societies. My main point was that in each case, modes of energy capture determined population size and density, which in turn largely determined which forms of social organization worked best, which went on to make certain sets of values more successful and attractive than others.
Foragers, I observed, overwhelmingly lived in small, low-density groups, and generally saw political and wealth hierarchies as bad things. They were more tolerant of gender hierarchy, and (by modern lights) surprisingly tolerant of violence. Farmers lived in bigger, denser communities, and generally saw steep political, wealth, and gender hierarchies as fine. They had much less patience than foragers, though, for interpersonal violence, and restricted its range of legitimate uses more narrowly. Fossil-fuel folk live in bigger, denser communities still. They tend to see political and gender hierarchy as bad things, and violence as particularly evil, but they are generally more tolerant of wealth hierarchies than foragers, although not so tolerant as farmers.