Table 3:

Decomposition of variance [95% CI] for each measure and subtest of cognitive ability

	A	C		G-E covariance	E

	Heritability ( h² )	Parental environment	Sibling environment		Non-shared environment
*Intake*
Performance IQ	.26 [.14, .40]	.02 [.01, .07]	.08 [.01, .14]	.06 [.01, .11]	.58 [.50, .64]
Verbal IQ	.36 [.26, .46]	.03 [.00, .10]	.07 [.00, .15]	.10 [.04, .14]	.44 [.34, .53]
Total IQ	.32 [.20, .45]	.04 [.01, .10]	.06 [.00, .13]	.11 [.04, .15]	.47 [.38, .56]
Block Design	.32 [.19, .45]	.03 [.01, .07]	.03 [.00, .10]	.09 [.03, .13]	.53 [.46, .60]
Picture Completion	.08 [.00, .21]	.02 [.00, .06]	.03 [.00, .10]	.01 [.00, .04]	.86 [.80, .89]
Vocabulary	.37 [.27, .49]	.04 [.01, .09]	.02 [.00, .09]	.12 [.05, .16]	.45 [.37, .55]
Information	.28 [.19, .39]	.02 [.00, .06]	.12 [.05, .18]	.05 [.01, .08]	.53 [.48, .60]
*Follow-up 3*
ICAR-16	.42 [.21, .64]	.01 [.00, .03]	.04 [.00, .15]	.03 [.00, .07]	.50 [.44, .57]
Vocabulary	.12 [.00, .25]	.10 [.03, .23]	.06 [.00, .15]	.08 [.00, .13]	.64 [.53, .75]

Note: 95% CIs are computed from each parameter’s 200 bootstrap iterations (Efron & Tibshirani, 1993) for each scale. Non-shared environment is computed by subtracting the heritability, parental environment, sibling environment, and gene-environment (G-E) covariance from 1. For full parameter estimates, see SI Table S12. Column values add up to 1, total phenotypic variance.