War and Peace: A Diachronic Social Biogeography of Life History Strategy and Between-Group Relations in Two Western European Populations

Abstract

We report successful diachronic replication of two major sets of prior findings in the social biogeography of human life history (LH) strategy: (1) the constructive replication of the diachronic changes in the latent hierarchical structure of intelligence in Britannic populations, but as presently applied to the latent hierarchical structure of human LH strategy, now cross-validated in both Britannic and Gallic populations; and (2) the diachronic replication in both Britannic and Gallic populations of the structural relations found synchronically among human LH strategy, between-group competition, and economic productivity in cross-sectional data on contemporary samples of both national and subnational polities. In addition, a supplementary methodological objective was: (3) the convergent validation of diachronic lexicographic measures of LH strategy with respect to more traditional non-lexicographic indicators of LH strategy, such as infant mortality rates, total fertility rates, and life expectancies. We obtained complete configural invariance across Britannic and Gallic biocultural groups, meaning that the same model predictors were statistically significant, but incomplete metric invariance, meaning that most but not all model parameter estimates were statistically equivalent in magnitude and direction. All new results obtained from diachronic data in Britannic populations were replicated almost perfectly in Gallic populations.