For the purpose of understanding the underlying mechanisms behind intergenerational associations in income and education, recent studies have explored the intergenerational transmission of abilities. We use a large representative sample of Swedish men to examine both intergenerational and sibling correlations in IQ. Since siblings share both parental factors and neighbourhood influences, the sibling correlation is a broader measure of the importance of family background than the intergenerational correlation. We use IQ data from the Swedish military enlistment tests. The correlation in IQ between fathers (born 1951-1956) and sons (born 1966-1980) is estimated to 0.347. The corresponding estimate for brothers (born 1951-1968) is 0.473, suggesting that family background explains approximately 50% of a person's IQ. Estimating sibling correlations in IQ, we thus find that family background has a substantially larger impact on IQ than has been indicated by previous studies examining only intergenerational correlations in IQ.
The B.E. Journal of Economic Analysis & Policy (BEJEAP) is an international forum for scholarship that employs microeconomics to analyze issues in business, consumer behavior and public policy. Topics include the interaction of firms, the functioning of markets, the effects of domestic and international policy and the design of organizations and institutions.