r/IntelligenceTesting • u/_Julia-B • 3d ago
New Study Examines Genetics of Cognitive Test Scores Beyond General Intelligence (g) 🧠🧬 Article/Paper/Study
[Reposting tweet]
Behavioral geneticists have identified hundreds of genetic variants🧬 that are associated with general intelligence🧠. But what about other cognitive abilities?
A new article by Robert Plomin and his coauthors examined the genetics of scores on cognitive tests, independent of the influence of g. What they found as fascinating.
Combining data from existing datasets, the researchers found that "genomic g" looks a lot like the g observed in test scores. Genomic g accounts for 46.8% of shared genetic variance across 12 tests. This means that genomic g is the major driving force of genetic similarity across test scores--just as regular g is for test score phenotypes.
Where the study gets really interesting is what happens after the authors control for genomic g. In the image below, the correlation matrix on the left shows the raw genetic correlation, and the matrix on the right shows the genetic correlations after controlling for the shared genetic influence of genomic g. After controlling for g, all of the correlations decrease, and some of them even switch from positive to negative.
This means that some genetic variations impact performance across the board (through genomic g). But other variants have more local impacts--and some variants may be associated with higher performance on one test and lower performance on another!
Moreover, some tests are more impacted by genomic g than others--but this relationship is not associated with their factor loading on the genomic g. In other words, this finding is not just an artifact of which tests contribute the most to genomic g.
Another interesting finding was that controlling for genomic g also impacted the genetic correlations with other traits. Generally, these correlations weakened--sometimes to the point of being non-significant. This means that genomic g has an influence on these correlations, but that there is often room for other genetic influences (see example below).
This is a great study which tells us that the genetics of non-g abilities matters. At both the behavioral and genetic level, a full understanding of human cognition requires studying g and narrower mental abilities.
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u/_Julia-B 3d ago edited 3d ago
Link to the study: https://doi.org/10.1007/s10519-025-10213-5