Researchers Find Dozens of Genes Associated With Measures of Intelligence (arstechnica.com)

An anonymous reader quotes a report from Ars Technica: We don't know a lot about the biological basis of our mental abilities -- we can't even consistently agree on how best to test them -- but a few things seem clear. One is that performance on a number of standardized tests that purport to measure intelligence tends to correlate with outcomes we'd associate with intelligence, like educational achievement. A second is that this performance seems to have a large genetic component. But initial studies clearly indicated that the effect of any individual gene on intelligence is small. As a result, the first genetics studies found very little, since you needed to look at a large number of people in order to see these small effects. Now, a new study has combined much of the previous work and has turned up 40 new genetic regions associated with intelligence test scores. But again, the effect of any individual gene is pretty minor. The team behind the new work took advantage of open data to pull together information from 13 different studies, which cumulatively looked through the genomes of over 78,000 individuals. While those individuals had been given a variety of tests, the authors focused on measures of general intelligence or fluid intelligence (the two seem to measure similar things). The genomes of these individuals had been scanned for single base pair differences, allowing the authors to look for correlations between regions of the genome and test scores. Two separate analyses were done. The first simply looked at each base difference individually. That turned up 336 individual bases, which clustered into 22 different genes. Half of these had not been associated with intelligence previously. To provide a separate validation of these results, the authors did a similar analysis with educational achievement. They found that nearly all of the sites they identified also correlated with that. In a second analysis, the authors tracked base differences that cluster in a single gene. Since there are more markers for each gene, this tends to be a more sensitive way of looking for effects. And in fact, it produced 47 genes associated with the intelligence test scores. Seventeen of those had been identified in the earlier analysis, which brought the total genes identified to 52, only 12 of which had been previously associated with intelligence test scores.

Comments

didn't you get the memo

[Swampash]

You're not allowed to talk about the possibility of there being a genetic basis for variations in intelligence. Because some genes are more common in certain ethnic groups than others, and then all hell will break loose and you'll get Bellcurved.

Re:didn't you get the memo

[Anonymous Coward]

There is also a long ugly history of even scientists ignoring scientific findings that are socially unacceptable.

Different mean and standard deviation of intelligence found in groups of people defined through genetic locus controlling for education, culture, diet, and socioeconomic status is one of them.

The person that can prove four decades of scientific evidence wrong will be quite famous. Until then, everyone tries very hard to ignore the evidence and pretend it doesn't exist, as this paper did.

Re:didn't you get the memo

[Michael Woodhams]

One issue is comparing heritability within a group with differences between groups.

The old argument goes something like this. Within middle class white Americans, IQ is highly heritable. Black Americans and new immigrants from Eastern Europe (this is around 1910 when there were many such immigrants) score much worse than middle class white Americans on IQ tests. Because IQ is heritable, the Blacks and Eastern Europeans must be genetically inferior.

There are (at least) two major problems with this line of reasoning. One is that the tests had a cultural bias. This can be as simple as people with English as a second language not understanding the instructions, or just lack of familiarity with the types of questions being asked. Another is neglecting the contribution of environment: the testees may in fact be less intelligent, but because of impoverished childhood rather than inferior genes.

A good example of this second point is height. Height is more heritable than IQ, but is also affected by childhood nutrition. As a people become affluent, average height increases, even though the genes are not changing.

Re:didn't you get the memo

[Jzanu]

But Jewish populations are genetically distinct, even between small sub-groups. As a whole they are farther from European clusters than many African, and of course are more closely related to Arabs from genetic drift measurements. Races are artificial and are scientifically meaningless; genetics is reality.

p hacking

[eis2718bob]

This is a textbook example of p-hacking. Note the plural in "measures of intelligence", along with "educational achievement" as dependent variables. Something was gonna show a correlation, to the vaunted oh point oh five. What a crock.

882. We don't even need the links for these anymore, just the number.

Re:Match against questions!

[SLi]

This "theory of multiple intelligences" is a quite popular narrative, but it's not empirically supported by studies. Rather, it seems that there is one "g factor", or general cognitive ability, that tends to explain quite well the "different kinds of intelligence". That is, any IQ test seems to be a good predictor of performance in any other IQ test, whether testing logical-mathematical, linguistic, spatial or some other "kind" of intelligence.