New Math Model Predicts Evolution of Large Complex Human Societies
Human society can be either simple or complex. Yet exactly how human societies evolve from small groups to the huge, anonymous complex societies of today has long remained a mystery. Now, scientists have tackled the question mathematically, accurately matching the historical record on the emergence of complex states in the ancient world.
In order to examine exactly how society evolves, the researchers created a mathematical model. This model was simulated within a realistic landscape of the Afro-Eurasian landmass during 1,500 BCE to 1,500 CE. This model was then tested against the historical record.
During this time period, horse-related military innovations, such as chariots and cavalry, dominated warfare within Afro-Eurasia. Geography also played a huge role; nomads living in the Eurasian Steppe influenced nearby agrarian societies, spreading intense forms of offensive warfare out from the steppe belt.
So why is warfare so important? Intense warfare is actually the evolutionary driver of large, complex societies. The interaction of ecology and geography as well as the spread of military innovations helps predict the selection for ultra-social institutions. In fact, scientists found that these ultra-social institutions that allow for cooperation in huge groups of genetically unrelated individuals and large-scale complex states are greater where warfare is more intense.
"What's so exciting about this area of research is that instead of just telling stories or describing what occurred, we can now explain general historical patterns with quantitative accuracy," said Sergey Gavrilets, co-author of the new study, in a news release. "Explaining historical events helps us better understand the present, and ultimately may help us predict the future."
In fact, the model led to sharply defined quantitative predictions that could be tested empirically. In addition, the model-predicted spread of large-scale societies was very similar to the observed one; the model was able to explain two-thirds of the variation in determining the rise of large-scale societies.
The findings are important not only for predicting how well societies will fare, but also show how past societies may have risen or fallen. The fact that warfare played such a large role in society formation also helps reveal a little bit more about human society evolution in general.
The findings are published in the journal Proceedings of the National Academy of Sciences.