

Nature v nurture? Please don't ask - tokenadult
http://www.timesonline.co.uk/tol/news/uk/science/article5986239.ece

======
xenophanes
"Much of the critical evidence has emerged through the study of twins.
Identical twins share all their DNA, while fraternal twins share only half -
they are no more closely related on a genetic level than are ordinary
siblings. Both kinds of twins, however, share a womb, a family and a cultural
environment. Comparisons between the two types can thus tease out the extent
to which inheritance is important."

Except that different kids have different experiences growing up. The same
family does not mean exactly the same life. It's just not true that genes are
the only difference between fraternal twins.

~~~
miloshh
Of course, but the point is, identical twins are consistently more similar
than fraternal twins.

Furthermore, identical twins are about as similar when growing up together, as
when growing up apart.

~~~
xenophanes
This can all be better explained by interactions between culture and genes,
than by just genes. But the studies tend to ignore those, because they're too
hard to deal with.

(If anyone knows a twin study which does adequately deal with gene/culture
interactions, please post it.)

------
mynameishere
Of course, when discussing "nature" in this context, it is always between two
humans. Why, how's the nature/nurture debate between humans and skunk cabbage
going? Of course, nature is highly determinant there. When you compare a very
stupid human, and a very intelligent human, you are _in an absolute sense_
comparing two extraordinary creatures whose extraordinariness is wholly
genetic. Their itty-bitty differences (auto mechanic vs. auto engineer) are
how we measure ourselves in a power-spectrum and skew our perceptions.

It doesn't matter: Private sector eugenics is already emerging and will settle
all bets.

------
tokenadult
"The concordance between identical twins, however, is rarely 100 percent -
their IQ scores, for example, tend to be around 70 percent similar, compared
with around 50per cent for non-identical pairs. By definition, inheritance
therefore cannot be the only factor involved: if it were, identical twins
would always turn out the same."

Surely "percent" is the wrong term here, which is puzzling, because why
wouldn't the author of the submitted article, who is also the author of the
book the article is based on, use the correct term?

~~~
jballanc
Take a regression correlation, multiply by 100, and you have a crude sort of
"percent". People intuit percent better than more complex (yet probably more
mathematically rigorous) comparisons. If the book is written for a lay
audience, this seems like an appropriate term.

~~~
tokenadult
That probably is where his "percent" is coming from, but I'm so used to
reading even popular literature that doesn't dumb things down like that
(preferring to explain typical ranges of correlations) that it was jarring to
read that in the newspaper article. Maybe the newspaper editors imposed that
on an author who does better in his book.

But what exactly does it MEAN to say "their IQ scores, for example, tend to be
around 70 percent similar" when IQ scores have their own scale?

------
phugoid
What I find more interesting than nature and nurture here is the censorship of
scientific research.

Many of us would like to base our cultural views, morals and laws on the
findings of scientific research. It seems more reasonable than the flying
spaghetti monster. But are we really prepared to change our views where the
science doesn't match up?

On the other hand, I don't think anyone expects science to always be "squeaky
clean", free of all political influence.

------
jwb119
>Nature works through nurture, and nurture through nature, to shape our
personalities, aptitudes, health and behaviour. The question should not be
which is the dominant influence, but how they fit together.

Interesting article

------
trapper
Clones FTW. Until we can clone and adjust environments to experimenters
desires, the jury is out.

