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. Author manuscript; available in PMC: 2010 Sep 15.
Published in final edited form as: Psychol Sci. 2010 Aug 2;21(9):1266–1273. doi: 10.1177/0956797610379233

Table 4.

Correlations Between Influences on Intelligence and Education at Three Levels of General Intelligence in Sweden and Minnesota

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.