DNA Tests for I.Q.

DNA Tests for IQ Are Coming, But It
Might Not Be Smart to Take One
Scientists have linked hundreds of genes to intelligence. One psychologist says it’s time to test school kids.
By Antonio Regalado

MIT Technology Review – April 2, 2018 -- Ready for a world in which a $50 DNA test can predict your odds of earning a PhD or forecast which toddler gets into a selective preschool?

Robert Plomin, a behavioral geneticist, says that’s exactly what’s coming.

For decades genetic researchers have sought the hereditary factors behind intelligence, with little luck. But now gene studies have finally gotten big enough—and hence powerful enough—to zero in on genetic differences linked to IQ.

A year ago, no gene had ever been tied to performance on an IQ test. Since then, more than 500 have, thanks to gene studies involving more than 200,000 test takers. Results from an experiment correlating one million people’s DNA with their academic success are due at any time.

The discoveries mean we can now read the DNA of a young child and get a notion of how intelligent he or she will be, says Plomin, an American based at King’s College London, where he leads a long-term study of 13,000 pairs of British twins.

Plomin outlined the DNA IQ test scenario in January in a paper titled “The New Genetics of Intelligence,” making a case that parents will use direct-to-consumer tests to predict kids’ mental abilities and make schooling choices, a concept he calls precision education.

As of now, the predictions are not highly accurate. The DNA variations that have been linked to test scores explain less than 10 percent of the intelligence differences between the people of European ancestry who’ve been studied.

Even so, MIT Technology Review found that aspects of Plomin’s testing scenario are already happening. At least three online services, including GenePlaza and DNA Land, have started offering to quantify anyone’s genetic IQ from a spit sample.

Others are holding back. The largest company offering direct-to-consumer DNA health reports, 23andMe, says it’s not telling people their brain rating out of concern the information would be poorly received.

Several educators contacted by MIT Technology Review reacted with alarm to the new developments, saying DNA tests should not be used to evaluate children’s academic prospects.

“The idea is we’ll have this information everywhere you go, like an RFID tag. Everyone will know who you are, what you are about. To me that is really scary,” says Catherine Bliss, a sociologist at the University of California, San Francisco, and author of a book questioning the use of genetics in social science.

“A world where people are slotted according to their inborn ability—well, that is Gattaca,” says Bliss. “That is eugenics.”

Finding the genes

To psychologists, IQ tests measure something called “g”—the general factor of intelligence. People who are better at math, spatial reasoning, verbal ability, and other skills that tests can measure have higher g.

And that’s not all. The g factor is strongly correlated with income, happiness, health, and life span. More g seems to be a good thing all around. To Plomin it’s the “omnipotent variable” in life.

It’s also highly heritable. Comparisons of twins, both identical and fraternal, separated at birth or raised together, had shown that genetics must account for more than half of intelligence—a huge effect for genes. The rest is due to your schools, your diet, and other environmental factors.

https://www.technologyreview.com/s/610339/dna-tests-for-iq-are-coming-but-it-might-not-be-smart-to-take-one/