On the Causal Relationship between IQ and GDP:An Instrumental Analysis

Although a substantial positive correlation between IQ and GDP per capita has been established at the national level over the past two decades (e.g., Lynn & Vanhanen, 2012), the causal direction of this association remains a topic of ongoing debate. In this study, we use a non-recursive path analysis with two different instrumental variables to further investigate the issue. The results of three analyses, each using two distinct instrumental measures, strongly indicate that IQ is the causal factor influencing GDP, rather than GDP causing changes in IQ. This finding supports the original hypothesis proposed by Lynn and Vanhanen (2002) and aligns with several other studies that have used alternative methodologies to explore the same relationship.