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Comment by rlanday | Hacker News Reader

The idea that there are no genes for IQ is completely ludicrous. Humans are clearly smarter than every other animal; this is entirely because we have different genetics. Additionally, the only possible way humans could've become smarter than other animals is that natural selection operated over time so as to increase the frequency of human genetic variants responsible for increased intelligence. This means there must also be genetic variants within our species that affect how smart we are relative to other humans, or this could not have happened.

The fact that intelligence is highly genetic in origin is extremely obvious. But the implications this fact has on how people interact with each other are extremely disturbing.

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How is it disturbing? Almost every aspect of human individuals is a random variable. What's wrong with intelligence being a random variable too, which could depend on some other aspect of the individual? I think making this a scary fact is what promotes the problems in discourse we see on this topic.

Intelligence is essentially what separates humans from other animals, and why we believe human lives to be more morally significant than the lives of other animals. To acknowledge that some people are smarter than others is essentially to acknowledge that their lives are worth more under humanity's current moral system.

Not only that, it also means people will likely try to "solve" poverty in Africa and elsewhere by getting rid of the natives and populate it with higher IQ people, as eugenecists were proposing right after Darwin came up with his theory of evolution.

And if you read the above statement and think "I certainly do not think that way, that's nuts", keep in mind how many others may read it and think "Well, that's science for you; heartless but honest."

That is my primary issue with this line of research. Clearly it can't be banned or made illegal, but I think it's worth acknowledging that racism and sexism are significant problems and to spend a little time considering how this line of research will make these problems even more intractable.

> Almost every aspect of human individuals is a random variable.

that's not even close to true. on the most basic level, you agree that certain traits are heritable in totally predictable ways, yes? eye color is an example of this.

> that's not even close to true. on the most basic level, you agree that certain traits are heritable in totally predictable ways, yes? eye color is an example of this.

Eye color inheritance isn't "totally predictable"; this is so obviously wrong to anyone who's ever met more than a couple humans that perhaps I'm misunderstanding the assertion you're making here.

Come to think of it, I think you might be saying that _conditioned on the alleles you receive_, there are traits that are fully predictable. In that case, I think you're just misunderstanding the comment you're responding to, since conditioning on the alleles received is begging the question.

Alternatively, you may not know what a random variable is: https://en.wikipedia.org/wiki/Random_variable. It doesn't mean that the trait is "random" in the colloquial sense of uniform distribution across all possible values.

Eye color in humans pretty closely follows the Dominant/recessive allele characteristics from classic Mendelian genetics. If you show me a person's family tree and I notice that all 4 of their grandparents have brown eyes I can predict with almost total certainty (barring new mutations or epigenetic effects) that they will have brown eyes.

other combinations of eye color at the grandparents lead to predictable distributions of the expression of that trait in the grandchild generation. this may be what was meant by "random variable", but it's really a population effect so modeling it as a random variable is peculiar. it's not random at the level of the individual, or at least it isn't after the recombination phase of fertilization in the embryo.

given a genetic sample of an individual it is totally predictable what their eye color will be based on examining their genes. I don't see how this is begging the question.

> given a genetic sample of an individual it is totally predictable what their eye color will be based on examining their genes. I don't see how this is begging the question.

Right, this is what I suspected you may have been saying. I think we were talking past each other a bit.

I still don't think it makes much sense to challenge someone who says "X is a random variable" by saying "that's not remotely true, X is not a random variable if you condition on the probabilistic component of X". Well, duh.

And people who have mismatched eye color? Totally predictable?

There's more to the output than the blueprint.

Sexual selection contains much of that randomness.

When people talk about "genes for IQ" they mean genes that account for differences between people.

The genes that all humans share (most of them) contribute a lot more to intelligence. That's a different subject altogether.

Natural selection to increase intelligence on a group level is impossible unless there's variance in the group for natural selection to operate on.

https://en.wikipedia.org/wiki/Fisher%27s_fundamental_theorem...

"The rate of increase in fitness of any organism at any time is equal to its genetic variance in fitness at that time."

The genetic variation that got us here isn't necessarily the same as the variation that remains, though. Perhaps there used to be more variation?

(There is the Flynn effect, but that's too quick to be genetic. Whatever its cause is apparently more important than genetics?)

That's a good point, the amount of variation changes over time. I'd be extremely surprised if the current amount somehow fell all the way to zero though.

There's apparently some speculation (according to the Wikipedia article on the Flynn effect at least) that the Flynn effect is due to non-genetic factors, in which case the underlying genetic trends are being obscured. There's a claim that genotypic IQ could be decreasing but we're not seeing that reflected effect in phenotypes due to environment improvements (which probably won't continue forever).

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