Three, the third hypothesis we set out to examine is that regional IQ differences in Italy are also manifest in variables that can be regarded as correlates or effects of IQs, including stature, infant mortality, literacy, and years of education. This hypothesis is substantiated for all of these phenomena. Regional IQs are highly correlated negatively with rates of infant mortality in 1954–57 (r=−0.847), and 1999–2002 (r=−0.873). It is proposed that the explanation for these correlations is that populations with high IQs are more competent in looking after their babies, e.g. by avoiding accidents, and are able to give them better nutrition, which makes them healthier and more resistant to disease. An association between infant mortality and low IQ mothers has been reported by Savage (1946). These results corroborate studies showing that IQ is negatively related to mortality over the life span [...].
