On this week’s episode of The Insight (Stitcher and Google Play) we talk to Stuart Ritchie, a postdoc in Ian Deary’s lab, about recent developments in cognition and genomics. There’s a reason that Deary gets some time in She Has Her Mother’s Laugh; his group is publishing some really interesting work.
Before we get to the good stuff, Stuart gives us a quick review of general intelligence and why it matters. If you want a book-length treatment then his own book should suffice, Intelligence: All That Matters. Richard Haier’s The Neuroscience of Intelligence goes a little more into the “wet biology” aspect of the brain if that is more your style.
There are two reasons I wanted us to have Stuart on the podcast.
First, psychometrics is not a field which was hit by the replication crisis. It’s a pretty robust and reliable discipline. Companies such as the Educational Testing Service (ETS) rely on the predictive power of the constructs in the field to sell their products. And yet most well-educated people don’t really know much about intelligence testing except that it has been “debunked” by the Mismeasure of Man.
Because people don’t understand the history of intelligence testing (i.e., it enabled the meritocracy by removing the importance of “polish” and “good breeding”) it’s easy for American graduate schools to do things like removing the GRE as a criterion on admissions. Privately some academics have told me that this will mostly result in increasing the importance of undergraduate education and pedigree (because anti-GRE sentiment has become connected to “social justice” I think it’s removal is a fait accompli).
Second, the field of cognitive genomics is moving through a major turning point. A publication like this in January, A combined analysis of genetically correlated traits identifies 187 loci and a role for neurogenesis and myelination in intelligence, is going to be superseded in months. I’m not speculating. I know this as a fact, and so do many others. Where will we be in two years?
Ray Kurzweil has many ideas, some of them interesting, some kooky, and some of them wrong. But one idea he’s promoted which I think is correct is humans are not good at modeling exponential rates of growth. The field of psychometric genomics is now moving into the steep phase of ascent, as sample sizes go well above 1 million, and some researchers shift from proxy characteristics such as education and delve into raw intelligence test scores. Most people “outside of the know” are about to smash into the concrete before they even know it’s coming up at them….
With all these intelligence genome-wide association studies being performed, someone really needs to measure the degree to which the associations are driven by indirect genetic effects from relatives (see http://science.sciencemag.org/content/359/6374/424). Only around one half of the variance explained by education genetic association results is due to direct effects. I expect that it is a bigger fraction for intelligence genetic associations, but it should be measured before these results are interpreted as simply reflecting the direct effect of genetic inheritance.
But I insist that the facts need to care about my feelings! My feelings are not ready for these unpleasant facts. I am unhappy, therefore these people are evil.
Cognitive ability is one trait. I’m interested in seeing what the underlying genomics for executive function turn out to be. What kind of CRISPR and other kinds of gene therapies can we cook up in order to allow adults (like you and I) to improve ourselves with regards to these traits?
Razib:
Similar to genes involved in pigmentation, do you think that in the case of the potentially hundreds of IQ related genes, that we will find populations where these genes express very differently due to that populations average genetic architecture?
not impossible. we don’t know.
the arch of height in pygmies seems a little different cuz of recent selection last i checked.
“A publication like this in January … is going to be superseded in months.”
So, the rumored IQ GWAS Of Doom paper is still in the throes of peer-re-re-review, then?
I’d gotten the impression that it was already in press, given all the pre-emptive “tread cautiously” essays that I’ve been seeing lately.
It was a good discussion, like all of the ones I’ve listened to so far. You need better advertising.
Gentle Comment : Book link erroneously points to Zimmer’s Book instead of Ritchie’s.