Well, for the most part genetics are in fact important and if I were to have read these studies a few years ago I might have agreed. However now, I can disagree on the basis that they have a bad research paradigm, very few cognitive developmental studies actually consider critical periods in nervous system development.
Either way, I'm sure there will be more research put into this topic soon enough as the neuroscience field begins to continue to grow.
Disagreeing with the conclusions of the study (not a view that I share), however, does not equal - and cannot equal - having proper evidence to assume the opposite conclusion. On that note, though, can you cite specific studies that you take issue with and, perhaps, state how you would have designed it differently?
The idea that IQ could be primarily an environmental thing seems absurd to me, however. "Giftedness" is far more than doing well in school, as many have mentioned. It's your inherit ability to learn being far greater (at least by 30 points) than the average. It goes down to actual understanding, processing information, ways of thinking/viewing the world, etc - all things that are primarily cognitive. A stable, good environment may help teach a child to read, do a math problem or think critically; but it can't give them that. On the reverse, someone could never learn to read and still be gifted/genius.
Once again, as an anecdote (which, I know, doesn't empirically prove anything; but is still of value), I had extensive trauma between the ages of 0 - 3 (a major time for brain development). I was in a violent household, subject to violence, limited access to anything academic (I had a couple hours each day in a daycare) and had very little attachment with any one caregiver - certainly not my parents. I still taught myself to read (at said daycare). I still taught myself to write. I could still understand abstract concepts. I could still understand those mathematical concepts. I wouldn't deny that this had an impact at all - as I said, I do think environment can have an effect and have the ability to raise/lower IQ points by (perhaps) a few points; but it certainly seems to be contrary to what you are saying.
On the flip side, I think it is fair to say that the majority of special needs children - in this discussion, specifically those with mental ******ation - come from anything other than stable, average environments. Many of these now get early intervention. They continue to get it through the rest of their education. Yet, though with a lot of work some may end up a bit better than when they started, the impact is not significant.
I believe genetics have the greatest influence on how one develops during those periods you mentioned and there seems to be more studies suggesting this than the reverse.
