I agree with the criticisms but don't agree that they invalidate twin studies to the extent that it's reasonable to believe cognitive traits are 100% nurture.

I agree with the criticisms but don't agree that they invalidate twin studies to the extent that it's reasonable to believe cognitive traits are 100% nurture. Yes, some older studies used odd statistical modelling. Yes, the specific number they put on heritability might be biased by a few factors. Yes, people lie on self-report surveys. Yes, adoption studies are biased by who agrees to sign up. Yes, in utero conditions falsely appear as heritability in twin studies. These are all valid criticisms in that they affect the precision of the measurement, but they're not enough to fully write off heritability as a whole. We've identified SNPs that correlate with IQ and education attainment, too, so there's an obvious mechanism. I think it's better to tell people the truth: achievement is a murky blend of nature and nurture interacting together, the factors seem to be important in different proportions for different people, and we only understand it imprecisely and at a population level. Further complicating the matter, ability at birth can be broken down into heritability and environmental factors before birth. Our chicken processor probably tried his hardest and can feel good. His daughter can do better if she's lucky and works hard. There's no need to take an extreme view where "talent" (meaning something like potential at birth) must be 0% or 100% of achievement, or to tell that to people, because from what we know it's somewhere in the middle.