Table 1.
Correlation of cognitive and brain functions between cotwins and the estimates from the ACE model
| Means (SD) | Correlations (95% CIs) | A, C, and E (%) etimates (95% CIs) | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| MZ (N = 54) | DZ (N = 24) | MZ | DZ | Best model | X2 | d.f. | p | A | C | E | |
| Task performance | 9.7 (3.1) | 9.6 (4.1) | 0.44 (0.07, 0.70) | 0.73 (0.26, 0.92) | CE | 3.29 | 4 | .51 | 56 (30, 75) | 44 (25, 70) | |
| FIQa | 99.6 (12.4) | 102.0 (15.8) | 0.71 (0.45, 0.86) | 0.44 (−0.17, 0.81) | AE | 0.91 | 4 | .92 | 74 (51, 88) | 26 (12, 49) | |
| Oxy‐Hb right prefrontal | 0.49 (0.82) | 0.09 (0.59) | 0.52 (0.14, 0.77) | −0.45 (−0.84, 0.25) | AE | 8.65 | 4 | .07 | 44 (8, 70) | 56 (30, 92) | |
| Oxy‐Hb left prefrontal | 0.52 (0.87) | 0.10 (0.90) | 0.37 (−0.05, 0.68) | 0.27 (−0.48, 0.79) | AE | 4.81 | 4 | .31 | 37 (3, 69) | 63 (31, 97) | |
| Deoxy‐Hb right prefrontal | −0.05 (0.45) | −0.12 (0.36) | 0.16 (−0.27, 0.54) | 0.30 (−0.40, 0.78) | E | 3.45 | 5 | .63 | 0 | 100 | |
| Deoxy‐Hb left prefrontal | −0.07 (0.39) | −0.02 (0.24) | 0.21 (−0.22, 0.58) | −0.11 (−0.72, 0.60) | E | 6.53 | 5 | .26 | 0 | 100 | |
FIQ, full‐scale intelligent quotient; MZ, monozygotic twins; DZ, dizygotic twins; A, additive genetic components; C, common environmental components; E, unique environmental components.
a
For participants aged 15 and under FIQ was evaluated with the WISC‐III, for participants aged 16 and over it was estimated by four subtests of the WAIS‐R.