Table A1.
Phenotypic and Cross-Twin (MZ/DZ) Correlations
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 1. Stroop | .28 / .15 | .10 / .04 | .13 / .11 | .01 / .06 | .15 / .12 | .13 / .06 | .12 / .10 | .16 / .10 | .16 / .13 | .01 / .00 | .03 / .06 |
| 2. AX-CPT | .16 | .36 / .18 | .23 / .18 | .09 / .07 | .21 / .12 | .17 / .15 | .20 / .16 | .24 / .18 | .27 / .24 | .14 / .10 | .11 / .13 |
| 3. Trail-Making Test | .16 | .27 | .37 / .21 | .13 /−.03 | .26 / .27 | .16 / .17 | .27 / .25 | .21 / .20 | .28 / .25 | .15 / .00 | .15 / .06 |
| 4. Category Switching | .06 | .11 | .13 | .14 / .00 | .07 / .07 | .06 / .05 | .12 / .00 | .10 / .10 | .14 / .09 | .06 / .01 | .03 / −.01 |
| 5. Letter-Number | .16 | .22 | .27 | .12 | .54 / .37 | .40 / .26 | .50 / .36 | .30 / .22 | .35 / .23 | .12 / −.03 | .14 / .04 |
| 6. Reading Span | .15 | .21 | .18 | .10 | .43 | .69 / .49 | .46 / .29 | .36 / .24 | .36 / .23 | .08 / .08 | .09 / .06 |
| 7. Digit Span | .14 | .18 | .26 | .10 | .59 | .51 | .66 / .42 | .33 / .23 | .38 / .26 | .14 / .00 | .13 / .06 |
| 8. AFQT - Age 20 | .18 | .24 | .25 | .12 | .31 | .35 | .30 | .72 / .43 | .69 / .41 | .01 / .01 | .03 / .04 |
| 9. AFQT - Ag 55 | .22 | .35 | .31 | .14 | .37 | .40 | .37 | 0.73 | .75 / .46 | .04 / .04 | .07 / .08 |
| 10. Simple RT | .01 | .13 | .07 | .02 | .10 | .13 | .14 | .02 | .10 | .39 / .10 | .34 / .15 |
| 11. Choice RT | .08 | .14 | .14 | .04 | .13 | .13 | .16 | .04 | .14 | .66 | .42 / .28 |
| 12. Age | −.16 | −.01 | −.05 | −.04 | −.03 | .09 | −.04 | .11 | .02 | .08 | .12 |
Note: Phenotypic correlations between all measures of the study are displayed below the diagonal. Twin 1 – Twin 2 correlations are displayed along and above the diagonal. Correlations for MZ twins are displayed on the left and correlations for DZ twins are displayed on the right. All correlations were based on age-residualized measures, except for those with age, which are the correlations between age and the non-age-residualized measures. Significant correlations are displayed in bold (p < .05).