One line stood out to me in particular, and it stood out due to a misunderstanding I had which I suspect many other readers have as well. The line is ”...there are significant heritable intelligence disparities between ethnic groups?”
At first read, this post implies that genes in different populations determine at least 50% of the variability in IQ, which is not true. I know your stance on saying the truth without regard to dumbing it down for audiences that shouldn’t read it, but I think this is one point where you should explain more. I conjecture that a nontrivial amount of people reading that line also have the same confusion I had.
An example from that article is that wearing earrings used to be highly heritable because you just had to look at whether they were female or male. As more people have started wearing earrings, the earring wearing trait has become less heritable. Similarly, IQ is not genetically determined and you see kids from low socioeconomic status way surpassing their parents IQ when adopted into higher socioeconomic status families.
On this particular point, while you are trying to succinctly say the truth, you are communicating a falsehood that needlessly alienates readers who have the same misunderstanding as me. I’m not refuting your point. I’m merely arguing that you should explain more here about a common confusion people will have when reading this.
[T]his is one point where you should explain more.
I will explain more. Total heritability of intelligence (in the US) might be as low as .40 (but probably isn’t). Heritability of intelligence due to being in one particular genetic bucket must be strictly lower than total heritability of intelligence. “Significant” can be below 50%.
An example from that article is that wearing earrings used to be highly heritable because you just had to look at whether they were female or male. As more people have started wearing earrings, the earring wearing trait has become less heritable.
This is true. Exactly what “heritability” means is beyond the scope of this post but Dynomight has a great article on what heritability means, mathematically. (Including how a trait can be more than 100% heritable and how changes to society can change the heritability of a trait.)
IQ is not genetically determined
My claim is that IQ has a genetic component. I am not claiming that IQ is 100% genetically determined. Are you claiming IQ doesn’t have a genetic component at all?
Thanks for the thoughtful reply, and the interesting read!
My claim is that IQ has a genetic component. I am not claiming that IQ is 100% genetically determined. Are you claiming IQ doesn’t have a genetic component at all?
I’m not claiming that IQ has zero genetic component, but I am saying that it’s not straightforward to conclude there are significant ethnic differences in IQ that are determined by genes.
To be specific, I’m arguing that IQ between ethnic groups in the US is likely much less than 50% determined by genes. Finding genes correlated with IQ doesn’t imply genes play a direct causal role, and there are very strong explanations that don’t involve genes such as socioeconomic status for example.
I’d wager around 0 to10% of the variation within normal IQ ranges is determined by genes for some cases, although that’s speculation based on evidence. I can’t find any rigorous scientific study of genes changing IQ (within normal ranges, as you can have genes that make the brain dysfunctional).
Heritability of intelligence due to being in one particular genetic bucket must be strictly lower than total heritability of intelligence. “Significant” can be below 50%.
Do you claim that heritability of intelligence due to being in one particular genetic bucket is closer to 50%? Or how much lower would you put it?
One line stood out to me in particular, and it stood out due to a misunderstanding I had which I suspect many other readers have as well. The line is ”...there are significant heritable intelligence disparities between ethnic groups?”
At first read, this post implies that genes in different populations determine at least 50% of the variability in IQ, which is not true. I know your stance on saying the truth without regard to dumbing it down for audiences that shouldn’t read it, but I think this is one point where you should explain more. I conjecture that a nontrivial amount of people reading that line also have the same confusion I had.
What is the confusion? That heritability is different from genetic heritability. This post enlightened me: https://bostonreview.net/science-nature-race/ned-block-race-genes-and-iq
An example from that article is that wearing earrings used to be highly heritable because you just had to look at whether they were female or male. As more people have started wearing earrings, the earring wearing trait has become less heritable. Similarly, IQ is not genetically determined and you see kids from low socioeconomic status way surpassing their parents IQ when adopted into higher socioeconomic status families.
On this particular point, while you are trying to succinctly say the truth, you are communicating a falsehood that needlessly alienates readers who have the same misunderstanding as me. I’m not refuting your point. I’m merely arguing that you should explain more here about a common confusion people will have when reading this.
I will explain more. Total heritability of intelligence (in the US) might be as low as .40 (but probably isn’t). Heritability of intelligence due to being in one particular genetic bucket must be strictly lower than total heritability of intelligence. “Significant” can be below 50%.
This is true. Exactly what “heritability” means is beyond the scope of this post but Dynomight has a great article on what heritability means, mathematically. (Including how a trait can be more than 100% heritable and how changes to society can change the heritability of a trait.)
My claim is that IQ has a genetic component. I am not claiming that IQ is 100% genetically determined. Are you claiming IQ doesn’t have a genetic component at all?
Thanks for the thoughtful reply, and the interesting read!
I’m not claiming that IQ has zero genetic component, but I am saying that it’s not straightforward to conclude there are significant ethnic differences in IQ that are determined by genes.
To be specific, I’m arguing that IQ between ethnic groups in the US is likely much less than 50% determined by genes. Finding genes correlated with IQ doesn’t imply genes play a direct causal role, and there are very strong explanations that don’t involve genes such as socioeconomic status for example.
I’d wager around 0 to10% of the variation within normal IQ ranges is determined by genes for some cases, although that’s speculation based on evidence. I can’t find any rigorous scientific study of genes changing IQ (within normal ranges, as you can have genes that make the brain dysfunctional).
Do you claim that heritability of intelligence due to being in one particular genetic bucket is closer to 50%? Or how much lower would you put it?