> According to Bouchard et al 1990, Bouchard & McGue 1981 we have the
> following correlations in intelligence (as measured by IQ tests)
> between:
>
> Identical twins reared together 0.86
> Identical twins reared apart 0.75
> Nonidentical twins reared together 0.57
> Siblings reared together 0.45
> Siblings reared apart 0.21
> Parent-Offspring reared by parent 0.36
> Parent-Offspring not reared by parent 0.20
> Adopting Parent-Offspring 0.19
> Adopted children reared together 0.02
>
> A correlation of 0.75 may sound like a dramatic similarity, until you
> realize that this means roughly 50% of the variance in intelligence
> can be attributed to genetics.
How do people who believe that upbringing accounts
for much of the variability of intelligence explain the fact
that the correlation coefficient between adopted children reared
together is only 0.02?
> Bouchard, T.J., Lykken, D.T., McGue M., Segal N. & Tellegen, A.
> (1990) Sources of human psychological differences: The Minnesota
> study of twins reared apart, Science 250, 223-228
>
> Bouchard, T.J & McGue, M (1981) Familial studies of intelligence: a
> review, Science 212, 1055-1059.
------------------------------------------------
Nicholas Bostrom
bostrom@ndirect.co.uk
*Visit my transhumanist web site at*
http://www.hedweb.com/nickb