I tweet links to research published in peer-reviewed scientific journals on human intelligence and other psychological traits.
10 subscribed
10 subscribed
10 subscribed
— Multiple intelligences exist
Environmentalists believe average differences between races in exposure to certain variables like poverty, nutrition, education, parenting, and health care explain the race IQ gaps.
So, if environmentalists don't believe genetic differences between races influence the IQ gaps between them, what do they think causes them?
One of the most popular environmentalist arguments in the race and IQ debate has been stereotype threat.
Some people have argued that the “cultural specificity” of intelligence makes IQ tests biased towards the environments in which they were designed, and therefore a particular test developed for a “white” culture may not accurately measure intelligence in a non-white one.
One type of rebuttal sometimes appearing in the popular media, but almost never made by scientists, can be expressed as “intelligence cannot be measured,” and also, relatedly, “IQ tests don't measure anything but one's ability to take IQ tests.”
A leading argument that has been used (more in the past than presently) against a hereditarian explanation for race IQ gaps relies upon the so-called “Flynn Effect,” named after the recently-deceased intelligence researcher James Flynn.
Some scientists claim that there hasn't been enough time for meaningful evolutionary changes to take place in the human brain in the 50,000 to 150,000 years since humans left Africa — changes that might have caused differences in IQ between geographically-separated groups.
In the last several threads, I've described the hereditarian explanation for racial differences in IQ.
In summary, even apart from GWAS/PGS, a compelling case for a genetic explanation for race IQ gaps can be made from the overwhelming evidence for the role of genes in IQ differences between individuals, the consistent large gaps in IQ and academic testing performance,...
This might be a good time to revisit GWAS, an advance in genomics which has identified the *specific* genetic variants associated with IQ and then had these variants' IQ-predictive values quantified by polygenic risk scoring (PGS or PRS).
A quick reminder thread to stress that while INDIVIDUAL differences in intelligence are due overwhelmingly to heritability/genes this does not necessarily mean that GROUP differences (like those between the races) are primarily genetically-influenced.
Over the last few previous threads, I've discussed some of the more well-known scientific findings and areas of research cited by hereditarians to argue for a genetic basis for racial differences in IQ. Now I'll very briefly discuss some less well-known ones.
So far I've talked about how the overwhelmingly genetic basis of individual differences in IQ, along with findings from transracial adoption studies, brain studies and population genetics, tend to support a hereditarian (genetic) explanation for the IQ gaps between races.
Hereditarians are quick to point out that one of the most reproducible findings in the science of human intelligence, across dozens of studies, is the association between brain size and intelligence.