Nature Trumps Nurture
Apparently it's all in the genes. This fascinating post comes from Tyler Cowen at Marginal Revolution:
Higher parental income predicts higher child income but only for biological children and not for adoptees. What about education? Sacerdote looks at that as well:
Having a college educated mother increases an adoptee's probability of graduating from college by 7 percentage points, but raises a biological child's probability of graduating from college by 26 percentage points.
The effect for father's years of education is even larger; about a ten times larger effect on biological children than on adoptees. Similarly, parent income has a negligible effect, small and not statistically significant, on an adoptee completing college but an 8 times larger and statistically significant effect on a biological child completing college.
I wonder how much these results would change if the researchers controlled for age at adoption. I suspect children adopted closer to birth would tend to score more like a biological children.
These results are fascinating.
The adoptees were Korean infants randomly assigned to American families approved for adoption. The adoptions took place between 1970 and 1980. The adoptees were therefore were aged 23-33 when the follow-up was done in 2003.