Table 2.
Within-twin correlations and estimated contributions of genes (A), shared environment (C), and unique environment/measurement error (E). 95% confidence intervals for each estimate are provided between parentheses.
| Outcome variable | rMZ | rDZ | Z | A² | C² | E² |
|---|---|---|---|---|---|---|
| Surface area | ||||||
| mPFC | .48*** | .21 | 2.03* | 0.48 (0.32-0.61) | 0.00 (†-0.28) | 0.52 (0.39-0.68) |
| TPJ | .41*** | .37** | .31 | 0.25 (†-0.60) | 0.21 (0.00-0.49) | 0.53 (0.39-0.68) |
| pSTS | .62*** | .38** | 2.13* | 0.61 (0.23-0.72) | 0.04 (†-0.36) | 0.35 (0.26-0.47) |
| Precuneus | .82*** | .28* | 5.7*** | 0.81 (0.73-0.86) | 0 (†-0.19) | 0.19 (0.14-0.27) |
| Cuneus | .74*** | .36** | 3.76*** | 0.70 (0.32-0.79) | 0.02 (†-0.36) | 0.29 (0.21-0.39) |
| Lingual | .73*** | .33** | 3.84*** | 0.70 (0.59-0.79) | 0.01 (†-0.34) | 0.29 (0.21-0.39) |
| Cortical thickness | ||||||
| mPFC | .23* | .15 | .54 | 0.17 (0.00-0.39) | 0.05 (0.00-0.31) | 0.78 (0.61-0.96) |
| TPJ | .31** | .31** | .00 | 0.09 (0.00-0.48) | 0.23 (0.00-0.42) | 0.68 (0.52-0.84) |
| pSTS | .36*** | .14 | 1.55 | 0.23 (0.00-0.43) | 0.05 (0.00-0.37) | 0.72 (0.57-0.88) |
| Precuneus | .55*** | .21 | 2.66** | 0.55 (0.26-0.67) | 0.00 (0.42-0.22) | 0.45 (0.33-0.61) |
| Cuneus | .71*** | .36** | 3.35*** | 0.73 (0.44-0.80) | 0.00 (0.00-0.26) | 0.27 (0.20-0.37) |
| Lingual | .60*** | .08 | 4.02*** | 0.56 (0.35-0.68) | 0.00 (0.00-0.16) | 0.44 (0.32-0.59) |
| Parent report | ||||||
| Prosocial behavior | .37*** | .08 | 2.36* | 0.45 (0.24-0.57) | 0.00 (†-0.14) | 0.55 (0.43-0.70) |
| Empathy | .75*** | .42*** | 4.02*** | 0.59 (0.39-0.79) | 0.15 (0.00-0.41) | 0.27 (0.20-0.35) |
rMZ = within-twin correlation for monozygotic twins, rDZ = within-twin correlation for dizygotic twins.
*
p < .05; ** p < .01; *** p < .001. Significant Z-scores indicate significant differences between MZ and DZ associations.† The 95% confidence interval bounds could not be estimated reliably.