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Comment by lkrubner | Hacker News Reader

This article, in part, overlaps with what we know about the Flynn Effect:

https://en.wikipedia.org/wiki/Flynn_effect

I'm not saying that the larger brain definitely explains the increase in IQ, but that is certainly a possibility worth exploring.

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One thing we know about the Flynn effect is that it plateaued in most places decades ago, and has been reversing in many places for a while.

The same Wikipedia article you linked discusses it in a few places, including here:

https://en.wikipedia.org/wiki/Flynn_effect#Possible_end_of_p...

If you account for differences in genetics and upbringing, then brain size has a correlation with intelligence. But it's only slight and other factors seem to be more predictive, like genetics and upbringing. Also it has not been established if bigger brains results in higher intelligence, or that higher intelligence results in a bigger brain.

Although nobody fully can explain why the Flynn effect occurs, we do know that there is no single cause, and it's therefor not possible for an increase in brain size to explain the Flynn effect.

That's super correlation vs causation, but also the explanation there seems straightforward to me: regardless of what IQ is or if it even exists, if you produce a standardized test that those who succeed in will be given (all other things being equal) better soecioeconomic outcomes, and it becomes a cultural institution over generations, then it's hardly surprising that you'll produce generations that progressively score better on the standardized test than previous generations, because that's what the society has been optimizing for by way of what it's rewarding. It doesn't necessarily have anything to do with intelligence (and this seems to bear with decreasing IQ results in Finland since last I heard they're not big on standardized tests there even though their practical education output is strong relative to other countries).

For comparison, ancient Jewish religious leaders memorized significant amounts of the Torah and culturally Torah memorization filled essentially the role that IQ does for modern western society (everyone wants to score favorably, and those who do extra well get special perks). Was it that their brains were physically wired for better memorization? Or was it that it became a cultural reward mechanism that promised socioeconomic rewards (status and wealth) which motivated generations upon generations to optimize for memorizing the Torah?

Admittedly we haven't quite reached the point of singing geometry puzzles to each other, but give it another few hundred years (or read Anathem ;)).

There's no evidence that people with higher IQs have more children than the middle and lower spectrums of IQ though. There was no survival pressure any time in the past 100 years that would explain it.

As for Jewish population having generally higher IQ, there must have been some far more dire population pressure beyond memorizing the Torah to explain the significant difference compared with other modern populations.

I think the point is that we don't observe evolution here, i.e. people with lesser IQ die more or reproduce less, but cultural adaptation. If high IQ scores are considered valuable, society creates environments that enable high IQ scores. Brains are pretty adaptable, even more so in the first 25 live years, and long exposure to an environment training for high IQ scores will result in higher IQ scores.

Correct (at least insofar as that's the assertion I'm making).

You're implying that the reason for the increase in IQ scores is the result of society suddenly focusing more on educational outcomes, but I think you're wrong about that. Society's ideas about childhood education and educational outcomes haven't changed that much over the last 60 years.

It's far more likely that these changes result from more immediate factors like improved teaching methods, improved ideas about health and pedagogy and environmental factors (like the removal of lead from gasoline, etc)

It’s not evolution insofar as the lower IQ scores are dying, but there is sexual selection. Mean reversion is from an approximation that does not hold for the subset of the population that is sexually selecting for intelligence. Two high IQ parents will on average produce offspring that have an even higher IQ.

Cane toads at the front of the cane toad expansion quickly evolve longer legs faster than one would expect if assuming there should be reversion to the mean.

Selection of high IQ women by high IQ men is a more recent phenomenon that has to do with having women in selective education so such pairings are a lot more common than they used to be, and you need both to be selected this way in order to avoid reversion to the mean.

>As for Jewish population having generally higher IQ, there must have been some far more dire population pressure beyond memorizing the Torah to explain the significant difference compared with other modern populations.

There actually is a body of research trying to explore this question, e.g.: https://pubmed.ncbi.nlm.nih.gov/16867211/

>There's no evidence that people with higher IQs have more children than the middle and lower spectrums of IQ though. There was no survival pressure any time in the past 100 years that would explain it.

It's true if you focus on the mid-high end of the spectrum, but people with low intelligence have a very hard time adapting to modern society.

Right, but wouldn't that generally mean that IQs remain static (if evolutionary pressure is the only influence)?

My understanding was that high and low IQ people tend to have fewer children, and in an age of contraception, impulsive people actually have the most.

When I listen to people from older generations, I feel they are smarter because they overcome harder times and achieved respectable results.

Education standards have dropped precipitously over the last 30-40 years.

Idk where you are located but this is likely not true

Just check out grade creep / inflation in US universities, it’s insane.

Cool, but apparently on average there is no evidence for that. Perhaps you're confusing experience with intelligence?

Not even Flynn believed the effect was real.

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