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IQ: Difference between revisions
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Additionally, this study indicated that income and IQ exerted distinct effects of sexual dimorphism in reproduction rates among men and women in the sample. That is, higher-income men had greater fertility than high-income women. In contrast, high-IQ men and women had similarly low fertility levels when the author controlled income and education. Hopcroft commented this might support the idea that high IQ, at least on the group level, may be maladaptive in the long run as it generates cultural selection pressures that counteract evolved fertility preferences among individuals of both sexes. An example that supports this contention would be the demographic transition phenomenon where more educated and wealthy countries generally have lower fertility the more these characteristics diffuse among the population.<ref>https://www.sciencedirect.com/science/article/abs/pii/0162309580900060</ref> | Additionally, this study indicated that income and IQ exerted distinct effects of sexual dimorphism in reproduction rates among men and women in the sample. That is, higher-income men had greater fertility than high-income women. In contrast, high-IQ men and women had similarly low fertility levels when the author controlled income and education. Hopcroft commented this might support the idea that high IQ, at least on the group level, may be maladaptive in the long run as it generates cultural selection pressures that counteract evolved fertility preferences among individuals of both sexes. An example that supports this contention would be the demographic transition phenomenon where more educated and wealthy countries generally have lower fertility the more these characteristics diffuse among the population.<ref>https://www.sciencedirect.com/science/article/abs/pii/0162309580900060</ref> | ||
The relationships between IQ and fertility vary cross-culturally, even among WEIRD (Western, Educated, Industrialized, Rich and Democratic) countries. In Sweden, income is associated with fertility among men and women, | The relationships between IQ and fertility vary cross-culturally, even among WEIRD (Western, Educated, Industrialized, Rich and Democratic) countries. In Sweden, income is associated with fertility among men and women, like in the US, with high-income women having lower fertility. Much of this effect, however, is driven by very low-income women being less fertile in Sweden than in the US. The relationship between income and fertility among men in Sweden is monotonic, with no diminishing returns for men's income and reproductive success at greater levels of wealth.<ref>https://www.tandfonline.com/doi/full/10.1080/00324728.2022.2134578</ref> | ||
Contrary to Hopcroft's GSS study, Kolk & Barclay (2021) found high IQ is associated with slightly greater fertility in Swedish men, independent of income and education. Much of this positive association is explained by higher-IQ Swedish men being more likely to be married than lower-IQ men. However, the effect was preserved when accounting for marriage.<ref>https://www.sciencedirect.com/science/article/pii/S0160289620300921</ref> This study was a replication of an earlier paper by the same two authors, which found the effect of IQ on attained fertility was most pronounced among the lowest IQ cohort of males, who had the lowest fertility.<ref>https://royalsocietypublishing.org/doi/full/10.1098/rspb.2019.0359</ref> | Contrary to Hopcroft's GSS study, Kolk & Barclay (2021) found high IQ is associated with slightly greater fertility in Swedish men, independent of income and education. Much of this positive association is explained by higher-IQ Swedish men being more likely to be married than lower-IQ men. However, the effect was preserved when accounting for marriage.<ref>https://www.sciencedirect.com/science/article/pii/S0160289620300921</ref> This study was a replication of an earlier paper by the same two authors, which found the effect of IQ on attained fertility was most pronounced among the lowest IQ cohort of males, who had the lowest fertility.<ref>https://royalsocietypublishing.org/doi/full/10.1098/rspb.2019.0359</ref> | ||