So purposeful fermentation might have played a role, just like fire, and hunting, and gathering techniques, and farming. It probably wasn't a revolutionary and sudden change, but gradual developments.
It's easy because it's exactly where we are now. Strip mining natural resources, runaway climate- and ecological change. And no way to solve it.
First, let's say you have two brains, one has IQ 160, the other has IQ 60. They are the same volume, neither suffers any brain damage. What is the IQ 60 brain doing?
Honestly, it seems like the Flynn effect has been a disaster upon the human race, when you look a bit better into history. People did live happier lives. All the supposed horrors seem to be a myth. There was more peace, love, honesty and goodness. Maybe they did know better.
It doesn't seem like "a hump" but more like a fundamental law of nature: exponential growth will collapse. And do so violently and with chaos.
I'm not talking about "the next 25 years" but more hundreds of years. Though even the timeline makes me anxious lately. I might see parts of civilization collapse due to exponential growth hitting a roof.
Because it certainly is a threat to economic growth. And also a threat to "national" safety if you decline, but your neighbor grows.
But it's undeniable that, on global, and millennial scale, exponential growth is unsustainable.
Our genes code for proteins which are expressed in different quantities and have different effects on multiple parts of our biology and growth that lead to operational differences in our brains that lead to patterns that might be considered "smarter" in some circumstances and is beneficial in some environments.
Take, for example, something near and dear to many of us on HN, hyperfocus.
Is being prone to hyperfocus on subjects that interest us making us "smarter"? Is it "beneficial"?
Well, sometimes, in some ways, in some environments. If you can hyperfocus on something that has economic value in a safe environment, you can make a lot of money and be very successful. If the things you want to hyperfocus on aren't particularly useful or you end up neglecting your actual job or relationships because of it, or if you're a caveman who was supposed to be keeping an eye out for lions and not counting how many leaves are on different kinds of plants, you'll be less successful.
Greater neuron density is probably still possible though. Just need to evolve to normalize the greater nutrient requirements.
https://worldpopulationreview.com/country-rankings/average-i...
The future belongs to the individuals, on any species, that are best adapted towards reproducing. Human beings are just another animal subjected to natural selection pressures. It seems that, usually, if you have too high of an IQ you simply refuse to have kids.
Convert the parking garage in the basement into a day care and you'll have phd-level employees for life. Changing jobs for even double the pay would be completely unaffordable.
The negative correlation between education and family size is a function of the cost of raising children in a city. If the cost is reduced then the correlation becomes nuetral or even positive. There is no such correlation in a rural setting. This is a bottleneck in the talent pipeline.
Consider this paper (from Indonesia) in which concluded that the relationship can change over time, as a function of policy:
Think of a high IQ man in the late 1700. He can see that having children incurs enormous costs, both financially, emotionally, in terms of time, freedom etc. He can choose to never marry, and just keep being a womanizer. He may have LOTS of unrecognized offspring, that are very hard to be attributed to him, and so pass his genes along. He just want to have sex, reproducing is not at all in his mind. Sex is good and he likes it, so he does it. That's the trick nature plays in order to make 1700 man to pass his genes.
Now in the 21st century, basically no high IQ man would go around having unprotected sex, since the costs associated nowadays are still enormous, probably even more so than 300 years ago, and today those costs are easily enforceable through the judicial system. So 21st century high IQ man, on average, will have a LOT less children than he used to have in the past. Sex is still good, and he will have a lot of it. But now nature's trick stopped working. The sex drive per se is not effective anymore when coupled with a high capacity brain that wants to avoid the costs of having to care for another human beings. So, this trait, high IQ, will be selected out of the gene pool over time.
In the case of high IQ women it's the same story. In the past, with a lot less effective and readily available contraceptive methods, smart women were probably a lot more at risk of having unexpected pregnancies. Nowadays, unexpected pregnancies are basically an IQ test for women.
edit: I searched a little bit on this and it seems that it was just a myth propagated by movies and a few very famous cases, i.e. Ted Bundy. But anyway, I do not see how you can make an argument from I wrote on the original post implying a correlation between psycopathy and high IQ. Is it the avoiding of having children, since it's an effective burden on the prospective father? It's just a fact, sexual drive was enough to make a man reproduce in the past. Not anymore. Natural selection wins again, the rules of the game changed, so you're out.
Really, the only two countries that are combining a knowledge economy with an expanding population are Israel and India, both of which essentially have a tech-worker economy subsidizing and intermarrying with a bronze-age economy. That seems like the likely actual solve, a few ivory tower cities surrounded by amish country. Every now and then an Amish tests into the cities or a city-zen absconds to a simpler life, but the net flow is generally intellectual country types moving into the tech hubs.