I have a suspicion that the “sweet spot” for mating is to be only somewhat smarter than than the average, but not so clever so as to be obnoxious.
In general estimates for the heritability of intelligence tend to be somewhat lower, on the order of ~50% rather than 80-90%.
It is due to the highly polygenic nature that both of these traits have been posited as candidates for a “good genes” model of sexual selection.
Update: First, people coming to this weblog for the first time should know that I moderate comments.
So if you leave an obnoxious one it’s basically like an email to me (no one will see it).
I think that’s doable with this data set, but I didn’t see it in the paper (tell me if I’ve missed something).
At some point we’ll have accurate high coverage whole genomes for many pairs, and we can ascertain whether it’s mutational load and pleiotropy more directly when it comes to correlations like this.
These are small correlations obviously, but it’s what we’d expect.
After the statistical modeling using a twin design there’s a lot of talk about sexual selection and the long arc of evolutionary genetics (e.g., additive genetic variation being exhausted by selection).
End Update One moderately interesting social science finding is that there is a positive correlation between height and measured intelligence (e.g., on an I. When I say it is highly heritable, I mean to imply that most of the variation in height in developed societies is due to genes (80-90%).
As it happens intelligence is somewhat similar in its genetic architecture, heritable due to small effects across many genes.
Whenever people posit a pleiotropic relationship between traits I am always curious about the possibility that the traits may be correlated (or not) in siblings.