Table 1 MZ and DZ correlation matrices of school performance (SP), self-control (SC), and Grit, conditional on fixed sex and SES effects, and random rater effects, and corrected for censoring.

From: The relationship of school performance with self-control and grit is strongly genetic and weakly causal

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  1. The correlations shown in dark blue represent the within-person correlations between traits, which are expected to be similar in MZ and DZ. The correlations shown in bold represent the within-trait twin correlations. These are higher in MZ than DZ, suggesting genetic influences on the traits. The correlations shown in light blue represent the cross-trait, cross-twin correlations (e.g., the correlation between school performance of one twin and self-control of the cotwin). These are higher in MZ than DZ, suggesting genetic correlations between the traits. 1 = Twin 1; 2 = Twin 2.
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