Abstract

Using a genetically informative design (about 2,000 twin pairs), we investigated the phenotypic and aetiological architecture of a broad construct of conscientiousness (including conscientiousness per se, effortful control, self-control, and grit). These four distinct measures were substantially correlated; the coefficients ranged from 0.74 (0.72–0.76) to 0.79 (0.76–0.80). Univariate genetic analyses revealed that individual differences in conscientiousness measures were mostly attributable to additive genetic factors, to an extent ranging from 62% (58–65%) to 64% (61–67%); we obtained no evidence that shared environmental factors were in play. Multivariate genetic analyses showed that the four measures used to assess conscientiousness were more genetically correlated, and that a common genetic factor accounted for over 84% of the genetic variance. Our findings suggest that individual differences in the four measures of conscientiousness are distinguishable at both the phenotypic and aetiological levels, and that the overlap was substantially attributable to genetic factors that might affect only a single set of genes.