War, Not Agriculture, Spawned Complex Societies

An interesting study/hypothesis that suggests that while agriculture was a part of why complex societies evolved, war was a much bigger reason (Wired):

To test the two competing theories, Turchin and company designed two mathematical models for predicting the spread of complex societies. One based only on agriculture, ecology and geography. The other included those three factors, plus warfare. Then, they used data from historical atlases to determine whether these models matched up with the way the different states and empires actually evolved.

The model that included warfare predicted about 65 percent of the historical variance, while the agricultural model explained only about 16 percent, suggesting that warfare was more important in the spread of social norms that lead to complex societies.

Turchin admits that the model is far from perfect — it includes no population data, for example — but for the most part, it was able to predict the spread of large-scale states between 1,500 BC to 1,500 AD. He also notes that whether or not simple societies were warlike is hugely controversial, but says that by the time their models start, warfare was widespread. “Proximate causes for warfare are numerous: competition for resources (mainly territory), revenge and strategic consideration (attack your enemy before they are ready to attack you),” he says.