How geography influences complex cognitive ability

© 2015. Evolutionary explanations for geography's influence on complex cognitive ability (CCA) imply virtually immutable components of between-nation IQ differences. Their weight vis-à-vis the weight of situational components was evaluated through an analysis of a 194-country data set. Additive effects of absolute latitude (AL) and longitudinal distance from Homo sapiens' cradle (LDC) explain Northeastern Asian higher, Sub-Saharan African lower CCAs. AL exerts cognitive influence directly and through socioeconomic development and evolutionary genetics whereas LDC does through evolutionary genetics; however, this occurs differently in Africa-Near East-Europe and elsewhere. The findings are understood assuming supremacy of contemporary UV<inf>B</inf> radiation→hormonal and climatic→socioeconomic mediators of the AL-CCA linkage whose effects are moderated by heterogeneous genetic and cultural adaptations to radiation and climate. Geography's cognitive effects are dynamic and public-policy actions may modify them.