Uma abordagem ecológico-evolutiva da violência: análise bioarqueológica das sociedades andinas pré-coloniais

Abstract

Violence is a polysemic, multifaceted, and controversial topic, but it is estimated that its physical and material manifestation has been present in the Homo genus since its emergence approximately 2 million years B.P. Among Homo-spiens, their collective practice became prominent in the last 5,000 B.P, and functioned as an important factor in the formation and decline of complex societies. This study analyzed, from ecological-evolutionary perspectives, the role of collective violence in the formation, maintenance and decline of complex societies in South America. Specifically, in Andean societies during the Middle Horizon (MH: 1350-950 B.P) and the Late Intermediate Period (LIP: 950-550 B.P). The objective was to analyze the differences in violence between the periods considered, and together, to observe the variation of the diet as a function of climatic and demographic variables, with the interest of understanding possible relationships between these economic factors and the practice of violence. Bioarchaeological data from head trauma in adults, and dietary pattern data by 13C (Carbon) and 15N (Nitrogen) isotopes of bone collagen from pre-colonial human remains from central Peru were analyzed. Additionally, data from climatic and demographic variables, such as mean annual temperature, mean annual precipitation, and Kernel population density, were considered. To observe differences in trauma between periods and diet variation, generalized linear regression models were applied. In addition, descriptive statistical analyzes and Fisher's exact independence tests were applied, both as analytical complements to the regression analyses. The results indicate that violence was less intense during MH compared to LIP, including lower levels of lethality. Regarding the diet variation, the values of 13C and 15N were more homogeneous in MH and varied in LIP. Regression analyses, as well as statistical description results, indicate that changes in temperature and precipitation had significant effects on dietary patterns in the MH and LIP. The differences observed between the two periods coincide with the increase in violence in the LIP. The results corroborate what the specialized literature says about the two periods. It is argued that violence was more controlled in MH due to the greater influence and social cohesion of the Wari imperial power. On the other hand, the fragmentation of autonomous political groups during the LIP increased the occurrence of collective violence. Changes in dietary patterns are significantly associated with political transformations, due to the decline of the Wari empire, as well as climate and environmental changes. The context of HM and LIP illustrates that cooperation and competition are not mutually exclusive in the social evolutionary process. As human behavioral ecology, evolutionary psychology, and multilevel selection theory show, we cooperate for the benefit of our groups, just as we cooperate to fight groups that threaten our groups. The scenario of greater internal cohesion during the MH, resulting in more controlled and systematized violence, and the greater diversification of groups in the LIP, resulting in more generalized violence, is compatible with this process.