Ecological Constraints on Violence Avoidance Tactics in the Prehispanic Central Andes

Prehispanic agricultural populations in the central Andes exhibit some of the highest rates of lethal and sublethal trauma ever recorded. Explanations for high rates of violence focus on what factors drove proactive conflict. While it is true that incentives for proactive violence must exist for high rates of trauma to ensue, it is far less recognized how ecological conditions may promote economic activities that constrain violence avoidance tactics and thus influence rates of violence. Here, we draw on models from behavioral ecology to generate predictions about how violence co-varies with environmental gradients, related subsistence strategies, and attendant defensive tactics. We hypothesize that rates of violence will be highest in marginal and variable environments where high-mobility subsistence strategies serve to reduce subsistence risk while increasing the costs of violence avoidance. Our results show that high elevation locations with variable topography where high mobility subsistence strategies are common exhibit the highest rates of generalized interpersonal violence. These results suggest that as ecological conditions become marginal and variable, risk-reducing subsistence strategies are emphasized, which result in increased exposure to violence. This study shows that environmental influences on the efficacy of violence avoidance tactics are important for explaining variability in rates of violence.