Given the results from Wand and Hoyer, I would expect it to just take time. It seems a pretty consistent pattern that many civilizations increase in complexity over time once they have adapted agriculture. Their scale-up takes around 2500 years and then plateaus. Also many of those complexity developments happened completely independently, e.g. China, the Incas and Egypt.
Given the results from Wand and Hoyer, I would expect it to just take time. It seems a pretty consistent pattern that many civilizations increase in complexity over time once they have adapted agriculture. Their scale-up takes around 2500 years and then plateaus. Also many of those complexity developments happened completely independently, e.g. China, the Incas and Egypt.