. Author manuscript; available in PMC: 2017 Feb 1.

Published in final edited form as: Dev Psychol. 2016 Feb;52(2):326–340. doi: 10.1037/dev0000075

Table 3.

Univariate Task Twin Correlations and ACE Estimates

	Twin Correlations^a		Variance Components (%)			Model Fit
Task	MZ	DZ	A	C	E	χ² (6)	p	RMSEA	CFI
Wave 1
Antisaccade	.55^*	.22^*	54^* [5]	0 [.00]	46^* [5]	3.21	.782	.000	1.00
Stop-signal	.51^*	.08	44^* [6]	0 [.00]	56^* [6]	10.41	.109	.061	.911
Stroop	.48^*	.29^*	38^* [17]	9 [.14]	53^* [5]	5.57	.473	.000	1.00
Keep track	.54^*	.25^*	53^* [5]	0 [.00]	47^* [5]	1.89	.930	.000	1.00
Letter memory	.57^*	.18^*	55^* [5]	0 [.00]	45^* [5]	7.50	.277	.035	.983
Spatial 2-back	.29^*	.14	25 [20]	2 [.17]	73^* [6]	4.56	.602	.000	1.00
Number–letter	.51^*	.29^*	48^* [16]	4 [.14]	48^* [5]	2.99	.810	.000	1.00
Color–shape	.34^*	.21^*	34 [19]	3 [.15]	63^* [6]	5.60	.469	.000	1.00
Category-switch	.53^*	.33^*	39^* [16]	13 [.14]	47^* [5]	3.47	.748	.000	1.00
Wave 2
Antisaccade	.61^*	.40^*	42^* [14]	19 [.13]	39^* [4]	2.05	.915	.000	1.00
Stop-signal	.27^*	.22^*	12 [20]	15 [.16]	73^* [7]	3.74	.712	.000	1.00
Stroop	.52^*	.08	49^* [5]	0 [.00]	51^* [5]	8.72	.190	.049	.956
Keep track	.60^*	.15	57^* [5]	0 [.00]	43^* [5]	6.34	.387	.017	.996
Letter memory	.69^*	.34^*	69^* [3]	0 [.00]	31^* [3]	0.81	.992	.000	1.00
Spatial 2-back	.55^*	.16^*	53^* [5]	0 [.00]	47^* [5]	9.13	.167	.052	.957
Number–letter	.51^*	.17^*	53^* [5]	0 [.00]	47^* [5]	11.29	.080	.068	.917
Color–shape	.32^*	.23^*	28 [19]	7 [.15]	66^* [7]	4.91	.556	.000	1.00
Category-switch	.50^*	.21^*	48^* [5]	0 [.00]	52^* [5]	5.23	.514	.000	1.00

Note. Standard errors in brackets. Variance components sum to 100%, within rounding error. MZ = monozygotic; DZ = dizygotic; A = additive genetic variance; C = shared environmental variance; E = nonshared environmental variance; RMSEA = root-mean-square error of approximation. CFI = confirmatory fit index. χ²/df < 2, RMSEA < .06, and CFI > .95 indicate good fit.

Correlations are maximum likelihood estimates (from Mplus) based on all data, adjusted for missing observations.

p < .05, determined with chi-square difference tests for the ACE models and with z-values for the correlations.