Or is the correct model something like: abuse can change things to worse, but any non-abusive parenting simply means the child will grow up determined by their genes? That is, we have a biologically set “destiny”, and all the environment can do is either help us reach this destiny or somehow cripple us halfway (by abuse, by lack of nutrition, etc.).
In an home environment within the normal range for a population, the home environment will matter little in a predictable sense on many traits compared to the genetic legacy, and random events/choices/biological-events/accidents/etc. There are some traits it will matter a lot on, and in a causal sense, the home environment may determine various important outcomes but not in a way that is predictable or easily measured. The other category of ‘nonshared environment’ is often bigger than the genetic legacy, so speaking of a biologically set destiny is misleading: biologically influenced would be a better phrase.
Has this been demonstrated for home environments in the developing world or sub-middle class home environments in the developed world? My prior understanding was that it had not been.
There are serious restriction of range problems with the literature. I believe that there is one small French adoption study with unrestricted range which produced 1 sigma IQ difference between the bottom and top buckets (deciles?) of adopting families.
I wonder if this what Shalizi alludes to when he says that IQ is closer to that of the adoptive parents than that of the biological parents.
I believe that there is one small French adoption study which produced 1 sigma IQ difference between the bottom and top buckets (deciles?) of adopting families.
(Both references describe the same study.) Capron & Duyme found 38 French children placed for adoption before age 2, 20 of them to parents with very high socioeconomic status (operationalized as having 14-23 years of education and working a profession) and 18 to parents with very low socioeconomic status (unskilled & semi-skilled labourers or farmers, with 5-8 years of education). When the kids took the WISC-R IQ test, those adopted into the high-SES families had a mean IQ of 111.6, while those in the low-SES families had a mean IQ of 100.0, for a difference of 0.77 sigma.
In an home environment within the normal range for a population, the home environment will matter little in a predictable sense on many traits compared to the genetic legacy, and random events/choices/biological-events/accidents/etc. There are some traits it will matter a lot on, and in a causal sense, the home environment may determine various important outcomes but not in a way that is predictable or easily measured. The other category of ‘nonshared environment’ is often bigger than the genetic legacy, so speaking of a biologically set destiny is misleading: biologically influenced would be a better phrase.
Has this been demonstrated for home environments in the developing world or sub-middle class home environments in the developed world? My prior understanding was that it had not been.
There are serious restriction of range problems with the literature. I believe that there is one small French adoption study with unrestricted range which produced 1 sigma IQ difference between the bottom and top buckets (deciles?) of adopting families.
I wonder if this what Shalizi alludes to when he says that IQ is closer to that of the adoptive parents than that of the biological parents.
Christiane Capron & Michel Duyme (1989), “Assessment of effects of socio-economic status on IQ in a full cross-fostering study”, Nature, 340, 552-554
Christiane Capron & Michel Duyme (1996), “Effect of Socioeconomic Status of Biological and Adoptive Parents on WISC-R Subtest Scores of their French Adopted Children”, Intelligence, 22, 259-275
(Both references describe the same study.) Capron & Duyme found 38 French children placed for adoption before age 2, 20 of them to parents with very high socioeconomic status (operationalized as having 14-23 years of education and working a profession) and 18 to parents with very low socioeconomic status (unskilled & semi-skilled labourers or farmers, with 5-8 years of education). When the kids took the WISC-R IQ test, those adopted into the high-SES families had a mean IQ of 111.6, while those in the low-SES families had a mean IQ of 100.0, for a difference of 0.77 sigma.
Thanks!