Table 4.
Variance component | Sweden | Minnesota | ||||
---|---|---|---|---|---|---|
−2 SD | 0 SD | 2 SD | −2 SD | 0 SD | 2 SD | |
Genetic | 0.53 (0.44, 0.62) | 0.55 (0.50, 0.59) | 0.56 (0.47, 0.65) | 0.57 (0.31, 0.86) | 0.38 (0.12, 0.67) | 0.28 (0.02, 0.57) |
Shared environmental | 1.00 (0.87,1.00) | 1.00 (0.94,1.00) | 1.00 (0.87,1.00) | 1.00 (0, 1.00) | 1.00 (0, 1.00) | 1.00 (0, 1.00) |
Nonshared environmental | 0.16 (0.11, 0.22) | 0.15 (0.10, 0.20) | 0.14 (0.09, 0.20) | 0 (−0.13, 0.13) | 0(−.13, 0.13) | 0 (−0.13, 0.13) |
Note: The table presents correlations at three levels of general intelligence: the mean, 2 standard deviations below the mean, and 2 standards above the mean. Numbers in parentheses are 95% confidence intervals. The Swedish data included only male pairs. The Minnesotan data included both male and female same-sex pairs.