Kathryn Paige Harden: ‘Studies have found genetic variants that correlate with going further in school’ theguardian.com/science/2021/s… - tricky stuff here...
It should be no surprise to anyone that children differ in ways that affect (not determine, but contribute to) how far they go in education.
Some of those differences are genetic in origin, others may be the result of variation in brain development (explaining why even identical twins may differ)
The relevant psychological traits that contribute to variation in educational attainment include intelligence (however you imperfectly measure it) as well as conscientiousness and some others
None of the above should be taken to suggest that social and environmental factors are not also hugely important in determining educational opportunities and success
In many instances such factors play by far the biggest role - comparing between developed and developing countries, for example, or between rich and poor regions within countries
In situations with more social equity of access and support, innate differences (genetic or non-genetic) may explain proportionally more of the variation in outcomes
Molecular genetic studies (led by @kph3k and others) have been able to identify some of the specific genetic variants that correlate with this measure of how far people have gone in education
And you can add up how many of these variants people have to give an aggregate 'polygenic' score, which explains 10-15% of the variance in educational attainment in some large samples
As shown in this paper by Plomin and von Stumm, these polygenic scores correlate across the whole range with performance on UK state exams (GCSEs) ncbi.nlm.nih.gov/pmc/articles/P…
So it's accurate to say genetic variation 'explains' some of the variance in educational attainment in the UK sample. But note the spread of values for any given polygenic score (shown more clearly here):
That means such scores have effectively zero predictive value *for individuals*. They show a trend across many people by averaging over all the other variables, but you can't do that for a given person
Here's one such study: Gene discovery and polygenic prediction from a 1.1-million-person GWAS of educational attainment ncbi.nlm.nih.gov/pmc/articles/P…
One important finding - the genes implicated are overwhelmingly enriched for ones expressed in the nervous system. This is not a surprise, but a very powerful reality check that results are not just tracking something spurious
That is, the genetic analyses (GWAS) and polygenic scores are not just tracking social stratification - if they were, there would be no reason why markers just for nervous system genes would be enriched
However, the functions of the implicated genes (for educational attainment or measures of intelligence) do not converge on specific pathways or processes...
The only enrichment is for genes involved in neurodevelopment very broadly. Which suggests what we recognise as "intelligence" very generally tracks how the brain is put together, but nothing more specific
Studies in the last few years have revealed something very... well, revealing! Some of the genetic effects identified in individuals are due to effects *in their parents*
Unless they're adopted, people obviously share genetic variants with their parents. An association between variant X in an individual and trait Y can sometimes be due to the effect of X in the individual's parents, affecting the individual's environment
This kind of "genetic nurture" (or "passive gene-environment correlation") is the case for educational attainment, as shown here: Comparison of Adopted and Nonadopted Individuals Reveals Gene-Environment Interplay for Education in the UK Biobank pubmed.ncbi.nlm.nih.gov/32302253/
Polygenic scores were much more predictive of educational attainment in non-adopted vs adopted people. This implies some of the genetic effects of variants carried are mediated by fact that their parents carry them too...
This is confirmed in the study below, which find strong effects on individuals of genetic variants carried by their parents that the individuals do NOT inherit!
You can track the non-transmitted variants and make a polygenic score just for them and it still explains a good chunk of the overall polygenic score variance in the next generation
All of which confirms something important - family environment (and probably wider social setting) matters a lot for educational attainment
Variants that genetically predispose parents to go further in education (and thus have higher income, access to better schools, etc.) thus positively influence offspring's education through non-genetic means
There is thus an inextricable interplay between genes, environment, and wider culture which loops across generations, with both genetic and social inheritance having a strong influence
Reading here about Higher-Order Thought (HOT) theories of consciousness, which make a lot of sense to me: plato.stanford.edu/entries/consci…
Basic idea is that conscious awareness (of a percept or an intention) requires a secondary representation - the recognition that you are having that percept or intention
That all fits with lots of neural and neurological findings, though there are many possible criticisms of this framework...
This book is brilliant. Incredibly precise exposition of how reasons - grounded in beliefs, desires, and knowledge - drive behavior
This is the kind of philosophy I really enjoy. No outlandish thought experiments, no semantic sleight-of-hand, no clever moves aimed to stump opponents... Just clear, rigorous analysis
One key insight: the distinction between a triggering cause (stimulus A -> action/outcome B) and a structuring cause (the reason *why* A->B)
Really excellent, insightful article highlighting crucial role of culture in understanding variation in heritability 👇 But I have a quibble... (thread below)
The article frames phenotypic variance as capable of being partitioned into a component explained by genetic variance and a component explained by environmental variance. 2/n
And it looks in detail at how environmental variance and gene-environment interactions (and therefore heritability) are all sensitive to cultural differences, clustering, sampling effects, etc. 3/n
I think @Lise_Eliot and colleagues have done a real service to the field in performing this exhaustive meta-analysis of the messy literature on sex differences assessed by neuroimaging
Longish thread: *Assessed by neuroimaging* is important here, as it’s an extremely gross level at which to look for differences, compared to what can be done in other animals (where lots of fine differences are observed).
So there could, in the first instance, be NO sex differences observed by neuroimaging and that would not have any bearing on whether differences exist in microarchitecture, distribution of cell types, synaptic connectivity, gene expression profiles, cellular physiology, etc.
This is a really interesting and important paper showing that very large samples are required to get reliable associations between brain imaging and behavioral phenotypes
The starkest conclusion is that the vast sea of literature to date claiming such associations is completely polluted by false positives (not a surprise given they never replicate)