There were significant sex differences in SDIT and all IQ composite scores.
MLEs of the phenotypic correlations for MZ and DZ groups for SDIT and FIQ are presented in Table 1 -- these are based on data where multivariate outlying twin pairs have been removed.
The MLE of the phenotypic correlation between SDIT and FIQ was -.
Low factor loadings in the full AE model were tested for significance and dropped where appropriate; only the unique environment path between SDIT and FIQ could be dropped.
The first additive genetic factor accounted for 36% of variance in SDIT and 32% of variance in FIQ, such that genetic influences that decreased SDIT increased FIQ.