Literacy not intelligence moderates the relationships between economic development, income inequality and health

Kanazawa (2006) presented data allegedly supporting a racist version of evolutionary psychology that claims that the populations of wealthier and more egalitarian societies live longer and stay healthier, not because they are wealthier and more egalitarian, but because they are more intelligent. The objectives of this study are: (i) to determine the relationship between IQ and literacy in Kanazawa's sample of countries and (ii) to reanalyse Kanazawa's dataset using measures of literacy in lieu of national IQ test scores.

Correlation and regression were employed.

National literacy scores across the countries in the sample are highly skewed. In spite of this, the literacy measures are highly correlated with alleged differences in national IQ (r = .83-.86). The measure of literacy together with economic development (GDPpc) and income inequality (Gini coefficient) control at least 59-64% of the variance in national life expectancy at birth.

There is no scientific justification for believing that alleged intelligence differences play any role in explaining international differences in health status. Measures of alleged national IQ scores are highly confounded with differences in literacy. Literacy is a key factor in the health of any community and policies designed to enhance the literacy of a population are expected to lead to significant improvements in health status.