kitchen table math, the sequel: executive function is genetic

Tuesday, July 29, 2008

executive function is genetic

well, well, well

who would have predicted this:

Recent psychological and neuropsychological research suggests that executive functions—the cognitive control processes that regulate thought and action—are multifaceted and that different types of executive functions are correlated but separable. The present multivariate twin study of 3 executive functions (inhibiting dominant responses, updating working memory representations, and shifting between task sets), measured as latent variables, examined why people vary in these executive control abilities and why these abilities are correlated but separable from a behavioral genetic perspective. Results indicated that executive functions are correlated because they are influenced by a highly heritable (99%) common factor that goes beyond general intelligence or perceptual speed, and they are separable because of additional genetic influences unique to particular executive functions. This combination of general and specific genetic influences places executive functions among the most heritable psychological traits. These results highlight the potential of genetic approaches for uncovering the biological underpinnings of executive functions and suggest a need for examining multiple types of executive functions to distinguish different levels of genetic influences.

Individual Differences in Executive Functions Are Almost Entirely Genetic in Origin
Naomi P. Friedman, Akira Miyake, Susan E. Young, John C. DeFries, Robin P. Corley, and John K. Hewitt
Journal of Experimental Psychology: General
2008, Vol. 137, No. 2, 201–225

Haven't read the article yet; when I have, and can (possibly) translate it into plain English, I'll post more.

Four thoughts for now:

Number one: so I guess tracking kids by executive function instead of ability to learn, as our middle school does, could be considered just the teensiest bit unfair.

Number two: if your kids are going to be attending a public school that tracks by executive function instead of ability to learn, redshirting your sons is a very good idea. Redshirting your daughters may be a good idea, too. Or just bagging the whole thing and teaching them at home: an excellent idea!

Number three: yet another piece of evidence that all those broader, bolder plans, many of which amount to nothing more than the intention to teach executive function (aka non-cognitive skills) to the children of the poor, are doomed to failure.*

Number four: constructivism must die.

The only folks on the planet who want to construct their own knowledge, and who can construct their own knowledge, are people with executive function to spare.

Ditto for projects.

wrong again

To tell the truth, I wouldn't have predicted this finding. No way would I have said EF would be 99% heritable. I think the highest heritability estimate for IQ I've seen is 80%, and I believe the "official" estimate is still 70%.

So....I would have put executive function at 70 to 80%.

My guess is this finding won't hold up. Last I heard (this was a while back, so the consensus could have changed), there were almost no aspects of life with 99% heritability. As I understand it, genes are always expressed inside an environment, whether that environment is social or biological ("biological" includes the presence or absence of other genes), and environments vary.

If readers who've studied genetics happen to stop by, I'd appreciate hearing whether this notion is evolving in some way I've missed.

Differential Development of Executive Functions in Adolescence - poster comparing boys & girls (pdf file)

* pls take this with a grain of salt: the bigger, bolder plan is doomed to failure, but not (necessarily) because executive function can't be taught


Anonymous said...

is there an ungated version of this paper somewhere? do you have a link?
in the abstract you post,
they don't say that exec func is highly heritable. they say that exec functions have a highly heritable common factor. that common factor might be a tool, for lack of a better word, that supports exec func. but without reading the paper, it's too difficult to say precisely what they mean.

Catherine Johnson said...

yes, true ---- "common factor" ----

Did you try Googling it with Google scholar?



I'll just email you the article.

Hang on.

Catherine Johnson said...

I just emailed it -- let me know if it doesn't come through.

I sent the poster, too, which looks quite interesting.