Macrohistorical and Evolutionary Dynamics of Between-Group Competition, Sociopolitical Complexity, and Differentiation-Integration Effects

Limiting similarity theory (LST) and the principle of competitive exclusion (PCE) affirm that the degree of allowable niche overlap predicts the occurrence of tolerant coexistence between two or more biotic entities. Attribute variation reduces conflict, whereby two biological systems in direct competition for the same type of finite resources are incapable of peacefully existing under conditions of constant population increase. Complex biotic systems often face trade-offs regarding the allocation of relevant bioenergetics resources to different facets of their organization, further increasing the likelihood of attribute differentiation-integration. Evidence in support of the aforementioned perspectives has been found across biological entities, including human societies. Multilevel selection (MLS) theory provides a complementary framework for understanding the evolution of human sociopolitical systems, whereby within-group cooperation is sustained by ultrasocial institutions that can be employed for competition with other groups, such as in warfare. We gathered and analyzed data on sociopolitical complexity, military technologies, and differentiation-integration effects for 360 historical polities (13,000 BC-1895 AD) from the Equinox 2020 database. A cascade model detected a positive effect of Time on the evolution of military technologies. In turn, Military Technology negatively influenced the level of Military Technology Differentiation-Integration, indicating that some polities specialized in developing military technologies in response to local challenges, a finding consistent with LST and PCE. The model revealed that whereas Military Technology increases Sociopolitical Complexity, a result supportive of MLS, Military Technology Differentiation-Integration had a significant and negative influence on this criterion variable. Greater Sociopolitical Complexity also negatively influenced the degree of Sociopolitical Differentiation-Integration.