I had once stated in the comment section of this blog that the correlation between IQ and income was higher in the U.S. than in the rest of the developed world. I had based this claim on various studies I’ve seen reported, but on page 103 of this book, it states that a meta-analysis showed the IQ-income correlation is no higher in the U.S..

I would have expected the IQ-income correlation to be higher in the U.S. because the U.S. is a country where you can get ridiculously rich. Understanding the value of money more fully, I would have expected high IQ Americans to be more motivated to pursue it, considering there was so much more to be made and that this would have increased the correlation between ability and income, but the studies fail to confirm this theory (though I doubt business income is well captured by such studies). I also would have expected the generous social safety nets in other developed countries to have disincentived a lot of smart people from working hard, making the IQ-income correlation lower in other developed countries.

But one of the commenters here has long argued that elites outside North America are more selected for IQ because the colleges recruit more based on test scores than on other criteria. This argument is ironic because while other countries do test for academic knowledge acquired in school, the college system in the U.S. is unique in that it uses the SAT, which was specifically intended as an IQ test according to a FRONTLINE article:

The design of the SAT was based on the IQ test (see historical timeline) The French psychologist Alfred Binet created the first test of intelligence in 1905. It was to be used to identify slow learners so that teachers could give them special attention. This test would later be known as the IQ test–IQ standing for “intelligence quotient,” or the ratio of mental to physical age.

Because the SAT was devised as a tool to identify talented students from underprivileged backgrounds, it was thought of as a test that would measure an innate ability referred to as “aptitude,” rather than abilities that these students might have developed through school.

“When these tests were originally developed,” said Harvard social policy professor Christopher Jencks, “people really believed that if they did the job right they would be able to measure this sort of underlying, biological potential. And they often called it aptitude, sometimes they called it genes, sometimes intelligence.”

You would expect the country that deliberately tried to recruit their elites using an IQ test to have a higher correlation between IQ and income than other countries that simply tested students on how much they learned in high school, but since how much you learn in high school is largely determined by your IQ, colleges in other countries probably did a good job screening for IQ in spite of themselves.

This demonstrates that societies end up selecting their elites for IQ whether they intend to or not. Even a society that was actively hostile to IQ, would still need elites with important skills to run their institutions, and since important skills are highly correlated with IQ, it’s almost impossible to recruit useful skills without also recruiting IQ.

Indeed the fact that brain size roughly tripled as apes evolved into people shows that nature itself was selecting for intelligence, millions of years before tests or even schools were invented.

Smart people tend to get to the top naturally.

It’s interesting that now that IQ testing is controversial, the college board wants to deny that the SAT is an IQ test. The frontline article reports:

According to the College Board, the SAT now does not measure any innate ability. Wayne Camara, Director of the Office of research at the College Board told FRONTLINE that the SAT measures “developed reasoning,” which he described as the skills that students develop not only in school but also outside of school. He pointed out, for example, that students who read a lot, both in and out of school, are more likely to do well on the SAT and in college. The College Board says that the best way to prepare for the SAT is to read a lot and to take rigorous academic courses.

Elite colleges get to have their cake and eat it too. They are benefiting from a test format created by IQ researchers in recruiting high quality students, yet maintaining their liberal street cred by denying IQ. But if they really believe the SAT is only measuring developed skills, then they should use tests that directly measure academic knowledge like other countries do. But they don’t, perhaps because deep down, they believe the SAT is a better measure of IQ than tests used in other countries, even though tests used in other countries still measure IQ despite not being designed for that purpose. But since the SAT is a more efficient measure of IQ, they are able to give test scores less weight, which allows elite colleges to give more weight to subjective criteria while still keeping the average IQ of their students high.

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