Genetic determination of social class
Using twin studies, Charles Murray showed 2 decades ago that IQ is mainly genetically inherited and that IQ underlies social class. The rich are brighter; the poor are dumber. The findings below reinforce that. The researchers were able to identify the actual DNA behind that relationship. High IQ people and high status people had different DNA to low status and low IQ people.
The research also showed something else that people find hard to digest: That family environment matters hardly at all. That repeatedly emerges in the twin studies but flies in the face of what people have believed for millennia: That your kid's upbringing matters. It may matter in some ways (value acquisition?) but it has no influence on how bright the kid will be. So now we have confirmation from a DNA study which shows that both IQ and social status are genetically determined. Home environment has nothing to do with it. The genes which give you a high IQ are the same ones that lead to high social status.
People can perhaps accept the genetic determination of IQ but accepting the genetic determination of social status will be more jarring. The wise men all tell us that a good upbringing will make you more likely to get rich. It won't. What you have inherited in your genes (principally IQ) is what will make you rich or poor
To specify exactly what was found: In a representative sample of the UK population, children from high status homes were found to be genetically different from children from low status homes -- and the DNA differences concerned were also determinant of IQ
Genetic influence on family socioeconomic status and children's intelligence
Maciej Trzaskowskia et al.
Environmental measures used widely in the behavioral sciences show nearly as much genetic influence as behavioral measures, a critical finding for interpreting associations between environmental factors and children's development. This research depends on the twin method that compares monozygotic and dizygotic twins, but key aspects of children's environment such as socioeconomic status (SES) cannot be investigated in twin studies because they are the same for children growing up together in a family. Here, using a new technique applied to DNA from 3000 unrelated children, we show significant genetic influence on family SES, and on its association with children's IQ at ages 7 and 12. In addition to demonstrating the ability to investigate genetic influence on between-family environmental measures, our results emphasize the need to consider genetics in research and policy on family SES and its association with children's IQ.
Posted by John J. Ray (M.A.; Ph.D.).