When psychologists first started studying twins, they found identical twins much more likely to have similar IQs than fraternal ones. They concluded that IQ was highly “heritable”—that is, due to genetic differences. But those were all high socio-economic-status (SES) twins.
Erik Turkheimer of the University of Virginia and his colleagues discovered that the picture was very different for poor, low-SES twins. For these children, there was very little difference between identical and fraternal twins: IQ was hardly heritable at all. Differences in the environment, like whether you lucked out with a good teacher, seemed to be much more important.
In the new study, researchers found this was even true when those children grew up. IQ was much less heritable for people who had grown up poor.
Read the full, original story here: Poverty Can Trump a Winning Hand of Genes
- “Genetics-Poverty Link Questioned,” Scientist
- “Growing Up Poor Zaps Your Mental Abilities by the Time You’re Two,” Good
- “Key cancer gene ‘link to poverty‘,” BBC News