Stratification & Violence
How a society is structured affects both stratification and the level of violence it generates. Foraging societies exhibit less hierarchy than agricultural ones, which have far less stratification than industrial societies.
When societies generate wealth and incorporate it into their value systems, male-male competition increases. War, conquest, and colonization have been the repeated results.
The structural basis for wealth also influences male aggressiveness. Even centuries after lifestyles change, the values precipitating violence remain in place, culturally transmitted through generations.