Only in America: Cold Winters Theory, race, IQ and well-being

Cold Winters Theory (CWT; Lynn, 1991) offers a viable explanation for race differences in intelligence. It proposes that IQ gaps exist because of different evolutionary pressures faced by the ancestral humans who left Africa, compared with those who remained. Support for CWT comes by showing correlations between national temperature and IQ. Here we test whether temperature correlates with IQ (and other well-being variables) across the 50 U.S. states. Although human evolution is recent, copious and regional (Wade, 2014), insufficient time has passed for it to have operated on non-native residents of the USA. Instead, CWT must predict no difference—or remain agnostic—on the existence of state-level correlations between temperature and IQ. Nonetheless, even after controlling for race, temperature strongly predicts state: IQ, religiosity, crime, education, health, income and global well-being. Evolution is therefore not necessary for temperature and IQ/well-being to co-vary meaningfully across geographic space.