The Intelligence Wars Are Likely to Heat Up Again Soon

The intelligence wars look likely to start up again in the near future. For those of you who aren’t familiar with them, here’s the nickel version.

Variation in intelligence, as measured by IQ tests, is generally thought to be partly a result of genes and partly a result of environment and upbringing. This is hardly controversial since the same is true of lots of human characteristics, but in the case of IQ it’s inevitably bound up in racial politics: If intelligence is partly mediated by genes, then it’s possible that different races have different average IQs. This is the case that Charles Murray and Richard Herrnstein made two decades ago in The Bell Curve. The reason this is more inflammatory than, say, racial differences in eye color or curly hair should be obvious.

So far, there’s little persuasive evidence for racial differences in intelligence. What’s more, the evidence we do have is mostly ecological in nature, involving comparisons at a group level. That’s interesting, but it will never be conclusive. Eventually, if you want to make a case for or against racial differences, you’re going to have to get down to the biochemical level and take a look at genes that affect the cognitive factors that make up overall intelligence (short-term memory, pattern recognition, etc.). That’s been a pipe dream for years, but not any longer. Last month, a team of 30 researchers published a study showing correlations between 40 newly-discovered gene variations and scores on IQ tests:

We combined genome-wide association study (GWAS) data for intelligence in 78,308 unrelated individuals from 13 cohorts….All association studies were performed on individuals of European descent….Our calculations show that the current results explain up to 4.8% of the variance in intelligence and that on average across the four samples there is a 1.9-fold increase in explained variance in comparison to the most recent GWAS on intelligence.

You may not think that 4.8 percent is a lot, but it is. And the genomic revolution that led to these results is only a few years old. In another few years we’ll be up to 20 or 30 or 40 percent. Nor is this just about intelligence, either. Here’s a chart showing the association of the newly discovered genetic variations on different characteristics:

Over at Vox, Brian Resnick explains the dark side of this research:

As more people have their genomes sequenced, and as computers become more sophisticated at seeking out patterns in data, these types of studies will proliferate. But there’s also a deep uneasiness at the heart of this research — it is easily misused by people who want to make claims about racial superiority and differences between groups. Such concerns prompted Nature to run an editorial stressing that the new science of genetics and intelligence comes to no such conclusions. “Environment is crucial, too,” Nature emphasized. “The existence of genes ‘for’ intelligence would not imply that education is wasted on people without those genes. Geneticists burned down that straw man long ago.”

Also, nothing in this work suggests there are genetic difference in intelligence when comparing people of different ancestries. If anything, it suggests that the genetics that give rise to IQ are more subtle and intricate than we can ever really understand

This research can be easily misused, but it can also be properly used. It’s still way too early for it to point toward any conclusions about group differences in cognitive abilities, but in a few years it will start to provide meaningful real-world results. This doesn’t bother me too much since I think the research will show either zero or minuscule differences between racial groups. But it might not. You never know with science.


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as we head into 2020 is whether politics and media will be a billionaires’ game, or a playing field where the rest of us have a shot.

Please read our annual column about the state of journalism and Mother Jones' plans for the year ahead, and help us build an alternative to oligarchy by supporting our people-powered journalism with a year-end gift today.

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