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If you look at the complete collapse of fertility rates in the developed world, that is probably the strongest evolutionary pressure humans have faced for millennia.

It is a bit weird to me that the scientific press doesn't talk more about how evolutionary pressure applies here. I think that people are wary to talk about this because it can end up sounding like social Darwinism, or that they believe "Idiocracy" was a scientific documentary.

But it's inescapable, for example, that education rates are now strongly negatively correlated with fertility. While "level of education" is obviously not inherited genetically, I don't think it's too much of a stretch to hypothesize that genetic factors play a role in someone's educational attainment. And, currently, the more education you get, the less likely you are to reproduce (statistically, of course).

Sex evolved to feel really good because for most of human history having sex would usually, eventually lead to babies. Reliable birth control has fundamentally broken that link. Similarly, when a major factor preventing you from reproducing was starving to death, being smarter or cleverer was an evolutionary advantage. I'd argue that advantage no longer exists.

Another simple anecdote: I recently went to my uncle's funeral, and his family was very religious (Catholic). My father, on the other hand, rejected religion and raised us all atheists. My father has 6 descendants, my uncle 24. Again, "religiosity" is not a genetically inherited trait, but I think it would be foolish to believe genetic predisposition plays 0 role.

I say all this just to highlight that, eventually, the "collapse in birthrates" will take care of itself - people with a strong desire and ability to procreate will outcompete, at least in terms of offspring survival, their peers. This will have a huge, profound effect on world society that most academics are too scared to talk about.



> But it's inescapable, for example, that education rates are now strongly negatively correlated with fertility. While "level of education" is obviously not inherited genetically, I don't think it's too much of a stretch to hypothesize that genetic factors play a role in someone's educational attainment. And, currently, the more education you get, the less likely you are to reproduce (statistically, of course).

Far from inescapable, this is just a phantom of noisy data.

It's easy to find statistically communicative population slices where family size is quite high and so is level of education (ignoring that "level of education" is a culturally specific and disputable measure in the first place).

What we really see is that integration into the modern US/EU-inspired "universal middle class" urban culture, which now spans the globe, seems to correlate with lower birth rates and family sizes. But there are countless factors contributing to what makes that culture unique and that could easily be playing a role in the birth rates and family sizes.

That said, it does suggest that the this "modern" culture needs to induct outsiders in order to maintain its scale since its proving relatively poor at growing its own population among insiders. What that means for the future is unclear, and if you're personally all in the on the "modern", it can easily look concerning or even bleak in the way you describe.


You're mistaken. Polygenic scores for educational attainment correlate negatively with fertility in the US, UK and elsewhere (in fact, AFAIK everywhere it has been tested). So it's not just because people in poor countries have more kids.

Note also that natural selection is about correlation not causality. If an lab accident blows up MIT, that will select against intelligence, even though intelligence wasn't causal.


I highly doubt birth control has altered the selection process in humans in the span of two or three generations.

I think you're right for the wrong reasons. Correlation does not equal causation. I think it's very clear it's our modern lifestyle. Our diet. Many of us are over weight. Most of us are sedentary. We're consuming higher percentage alcohol and weed. We're consuming other drugs. There are microplastics in our blood stream and the food we eat. There are chemicals like BPAs that were in our products for years before we removed them. Pollution. The list goes on. I would rule out these factors first before ever considering the idea that evolution is at play.


> Correlation does not equal causation.

The fact that you have said this makes me think you have misunderstood my point.

I am not arguing that genetic differences are responsible for any change over the past couple generations. I am strongly arguing that there is now an enormous new selection pressure, i.e. a new factor that strongly affects fertility rates, and over time (and, perhaps a very long time) that genetic inheritance will respond to that selection pressure. That is inherently how evolution works.

People love to say "correlation is not causation", but all evolution really works with in the first place is correlation. That is, the environment changes, and then organisms that happen, through "the genetic lottery", to not be able to reproduce in that new environment are outcompeted by those organisms that do. My argument is that the environment that determines whether humans reproduce has changed drastically over the past ~100 years or so, and that this will affect which genes are likely to be more prevalent in the future. I am not arguing this genetic change has already happened.


> But it's inescapable, for example, that education rates are now strongly negatively correlated with fertility.

You can easily say that city dwelling is strongly correlated with higher education rates, and higher noise pollution, therefore high noise pollution is strongly negatively correlated with fertility. Correlation doesn't equal causation.

> Reliable birth control has fundamentally broken that link.

Reliable birth control has severely reduced unwanted pregnancy, but there's a whole host of people who would like to have children that can't.




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