Does intelligence explain the association between generalized trust and economic development?

Both generalized trust and intelligence are correlated with economic development. However, recent research has shown that trust and intelligence are themselves correlated, both across countries and among individuals. Theory suggests that causality runs from intelligence to trust at the individual level, which raises the possibility that the association between trust and development is explained by intelligence. Indeed, intelligence may cause both trust and development. Alternatively, development may lead to higher intelligence, which in turn gives rise to greater trust. Note that intelligence may cause trust not only because individuals with higher intelligence tend to report greater trust, but also because such individuals tend to be more trustworthy. This study analyzes data on trust, intelligence and economic development for 15 Spanish regions, 20 Italian regions, 50 US states, and 107 countries. In all four domains, there is a statistically significant positive relationship between trust and intelligence (r = .74, r = .74, r = .72 and r = .50, respectively). Moreover, partial correlations suggest that intelligence accounts for some or all of the association between trust and development in at least two out of the four domains.