
99% Genetic?  Individual Differences in Executive Function Are Almost Perfectly Heritable - nickb
http://scienceblogs.com/developingintelligence/2008/05/99_genetic_individual_differen.php
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Antiglobalism
Oh noes, genes might control our behaviour. Why is this issue always so
sensitive?

Here's one interesting study that suggests genes to a large extent determine
happiness:
[http://www.sciencedaily.com/releases/2008/03/080304103308.ht...](http://www.sciencedaily.com/releases/2008/03/080304103308.htm)

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nazgulnarsil
because of racism and sexism.

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giardini
a claim of 99% is too high for me to resist posting the following URL:

"Why Most Published Research Findings are False":
[http://www.marginalrevolution.com/marginalrevolution/2005/09...](http://www.marginalrevolution.com/marginalrevolution/2005/09/why_most_publis.html)

and

"Most scientific papers are probably wrong":
<http://www.newscientist.com/article.ns?id=dn7915>

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botbooty
to preempt common criticisms:

1) 99% is not unbelievably high, given that they used factor analysis to
improve the reliability of the measurements 2) this doesn't preclude a)
environmental influences that interact with genetic profiles nor b)
environmental influences which act on the mean value of a twin-pair's score
(the study's concerned with deviations from means within twin pairs).

thanks for the interest guys.

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tokipin
it looks like it's saying they only tested twins that shared the same
households. that might have an effect on the results (by not testing the same
genes in diverse environments.) though i can't grasp the statistics at a
glance

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xlnt
heritable does not imply genetic! it could just as well be due to parenting.
(i realize it's a twin study, just replying to the title)

and genetic does not imply the relevant genes being inherited have anything to
do with executive function. they could just as well be for, say, the right
appearance to cause parents to think they are smart and thus help them become
smart.

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botbooty
i have trouble seeing how these comments apply to the content of the post -
parenting influences are largely controlled (as you seem to indicate) and I
don't see how these heritability estimates could reflect something unrelated
to executive function. that's the whole point, they clearly have something to
do with executive function. one would assume that something like appearance
would show large unshared environment since kids dress differently, etc/

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emmett
I found this essay (<http://cscs.umich.edu/~crshalizi/weblog/520.html>) very
helpful in understanding what "heritability" really means, and why it's so
hard to control studies like this.

The short version is: think about how heritable something like "number of
arms" would appear in a study like this. It would appear that variance in arm
count is 100% environmental, since the only people who don't have two arms
lost one in an accident of some kind. Arm count is therefore not controlled by
genes!

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xlnt
very good link! thanks.

