“just as evolutionary biologists use phylogenetic trees constructed using genetic data to test evolutionary hypotheses, anthropologists have recently begun to use cultural phylogenetics to test hypotheses about human social and cultural evolution,”
Political complexity indeed grew slowly, bit by bit, with no sudden jumps from bands to chiefdoms or tribes to states.
“Political evolution, like biological evolution, tends to proceed through small steps rather than through major jumps in ‘design space,’” wrote Mace and Currie.
However, purely forward-marching models didn’t fit the data. There was evidence of societies marching backwards as well, and this didn’t follow the same step-by-step path. Societies could collapse.