Re: Gene supremacy (Was: Re: Meme supremacy)

Anders Sandberg (
Fri, 1 Aug 1997 14:21:29 +0200 (MET DST)

On Sun, 31 Aug 1997, den Otter wrote:

> Sure, prenatal conditions and upbringing will have their effect on things
> like intelligence (again: in the *broadest* sense of the word), but the
> original genetic programming is almost certainly the most important
> factor (by far). Various studies of uniovular twins have shown the dramatic
> similarities in both looks and personality.

Similarities in looks are rather irrelevant, and while personality
facts are important for intelligence they are not as tightly bound to
genetics as you make it sound.

According to Bouchard et al 1990, Bouchard & McGue 1981 we have the
following correlations in intelligence (as measured by IQ tests)

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.

Note that a lot of this genetic variance also is fairly tangential:
if you have genes giving you a better immune system there is a good
chance that you will be able to develop your mind more than if you
are constantly plagued by infections.

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.

Anders Sandberg Towards Ascension!
GCS/M/S/O d++ -p+ c++++ !l u+ e++ m++ s+/+ n--- h+/* f+ g+ w++ t+ r+ !y