It's not the first time I've heard Charlie say something scientifically questionable. I think science is his weak spot despite his efforts to be a generalist.
It’s very likely the other way around - the Chinese kids got better parents. Adopting kids from China isn’t cheap, so the parents very likely have financial resources. there are also significant background checks. There is a significant selection bias going on on the parent side.
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Spekulatius ,
I agree with your perspective . It seems very logical and probable that adopting young Chinese girls generally requires considerably more financial resources than the average American family could likely afford . Additionally ,I would think that the adopting parents would probably be very well educated and would be better prepared to plan for and foster a life-long learning environment for the adopted kids . Thus , it does not surprise me that these kids become more motivated by being nurtured and loved by well prepared parents . ( Maybe the children simply become products of their positive , constructive environments ?)
greenwave