[squarecat]

I will freely admit that most of what I attempted to read beyond the first few pages was over my head (and certainly my attention span), but the gist of my interpretation would be that humans are increasingly mating with sameness in mind, or as I will henceforth (egotastically--not a typo) call "self-identifying physiopsychological compatibility".

[aidenn0]

But increased mating with sameness in mind causes increased variability in phenotype. For example heights in the US span a larger range now.

[gwern]

No, he constructs his model specifically to leave the underlying genetics the same in a static population, as a simplification.