| together | apart | |
| height (cm) | ~2.0 | ~2.5 |
| weight (pounds) | ~4 | ~10 |
| intelligence* | ~3.5 | ~6.5 |
|
* points on the Binet IQ scale. The intelligence test is highly biased towards the socially dominant sub-population, but this can only strengthen rather than invalidate the result of the study. | ||
Carson, H. L. (1963) Heredity and human life Columbia University Press, New York.