Previous research into the origins of human violence and warfare has oftentimes been inconclusive and controversial. This paper examines two alternative theories as to the evolution of human violence using archaeological records on sharp force trauma (SFT) and blunt force trauma (BFT). The study is limited to 13 different California ethnolinguistic groups. Researchers find that violence is not predicted by sociopolitical complexity, but rather by environmental productivity. This supports the idea that in contexts of resource scarcity, the perceived benefits to engage in lethal aggression may outweigh perceived costs.