Scarr-Rowe effect
In behavioral genetics, the Scarr-Rowe effect, also known as the Scarr-Rowe hypothesis, refers to the proposed moderating effect of low socioeconomic status on the heritability of children's IQ. According to this hypothesis, lower socioeconomic status and greater exposure to social disadvantage during childhood leads to a decrease in the heritability of IQ, as compared to children raised in more advantaged environments. This hypothesized effect was first proposed by Sandra Scarr, who found support for it in a 1971 study of twins in Philadelphia. It was later replicated by David C. Rowe in 1999. It is considered an example of gene–environment interaction.Additional research
In 1980, Siv Fischbein replicated the Scarr-Rowe effect in a Swedish twin sample. In 2003, Eric Turkheimer and colleagues replicated the effect in an analysis of the National Collaborative Perinatal Project. A 2016 meta-analysis found evidence of the Scarr-Rowe effect only in the United States, but no evidence of such an effect in Australia or Western Europe. Turkheimer et al. similarly note that the effect has been replicated more in the United States than in other countries, and that even in the United States some studies have failed to replicate it. Based on their analysis of the Louisville Twin Study, they reported weak evidence for the hypothesis that was not statistically significant. Research since 2016 has likewise found mixed results, with one study finding an effect in USA, and another not finding one in Australia.
