On the sources of the height–intelligence correlation: New insights from a bivariate ACE model with assortative mating

• Published in: Behavior genetics Vol. 41; no. 2; pp. 242 - 252
• Main Authors: Beauchamp, Jonathan P., Cesarini, David, Johannesson, Magnus, Lindqvist, Erik, Apicella, Coren
• Format: Journal Article
• Language: English
• Published: Boston Springer US 01.03.2011; Springer Nature B.V
• Subjects: Adult; Algorithms; Aptitudes; Assortative mating; Behavioral Science and Psychology; Body Height; Clinical Psychology; Environmental aspects; Estimates; Health care policy; Health Psychology; Humans; Intelligence; Intelligence Tests; Likelihood Functions; Male; Mating; Middle Aged; Models, Genetic; Models, Statistical; Occupational stress; Original Research; Phenotype; Psychology; Public Health; Response rates; Social Class; Sweden; Twins; Sweden; New York; United States > US; Assortative mating; Intelligence; Genetic correlation; IQ; Height; Within-family correlation; Bivariate ACE model
• ISSN: 0001-8244; 1573-3297; 1573-3297
• DOI: 10.1007/s10519-010-9376-7

A robust positive correlation between height and intelligence, as measured by IQ tests, has been established in the literature. This paper makes several contributions toward establishing the causes of this association. First, we extend the standard bivariate ACE model to account for assortative mating. The more general theoretical framework provides several key insights, including formulas to decompose a cross-trait genetic correlation into components attributable to assortative mating and pleiotropy and to decompose a cross-trait within-family correlation. Second, we use a large dataset of male twins drawn from Swedish conscription records and examine how well genetic and environmental factors explain the association between (i) height and intelligence and (ii) height and military aptitude, a professional psychogologist’s assessment of a conscript’s ability to deal with wartime stress. For both traits, we find suggestive evidence of a shared genetic architecture with height, but we demonstrate that point estimates are very sensitive to assumed degrees of assortative mating. Third, we report a significant within-family correlation between height and intelligence suggesting that pleiotropy might be at play.