Using a genetically informative design (about 2,000 twin pairs), we investigated the phenotypic and genetic and environmental architecture of a broad construct of conscientiousness (including Conscientiousness per se, Effortful Control, Self-Control [Brief Self-Control scale], and Grit).
These 4 different 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 moderately attributable to additive genetic factors, to an extent ranging from 62 (58–65) to 64% (61–67%); we obtained no evidence that shared environmental influences were observed. Multivariate genetic analyses showed that for the 4 measures used to assess Conscientiousness, genetic correlations were stronger than the corresponding non-shared environmental correlations, and that a latent common factor accounted for over 84% of the genetic variance.
Our findings suggest that individual differences in the 4 measures of Conscientiousness are not distinguishable at both the phenotypic and behavioral genetic levels, and that the overlap was substantially attributable to genetic factors.
