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Why are our brains shrinking?

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Re: Why are our brains shrinking?

#81

Post by lumost »

algebraically wrote: post #5

Because we are being domesticated. Domesticated animals are all dumber than their wild counterparts. Every wild animal that ends up being domesticated ends up with a smaller brain. I should rephrase and maybe say that this doesn't necessarily mean the animals get dumber but they definitely change in the process of domestication and a smaller brain is one of those adaptations. [1] > The reduced amount of white matter…

Alternately, big brains are recessive/selected against in all circumstances except those from 6mya to 70kya. We've generally removed most selective pressure at this point, if having big brains is due to a combination of recessive traits we'd expect brain size to start shrinking.

Re: Why are our brains shrinking?

#82

Post by robbedpeter »

inawarminister wrote: post #58
bobthechef wrote: post #55

Earlier quoted context omitted.

I agree that smaller brain does not mean dumber. This is a very simplistic idea of what brains are for. Whales have huge brains, but I would guess that has more to do with their size. I don't understand what you mean by "generalist" vs "specialist". I think intelligence is related to why, for example, human beings lack armor, fur, and all sorts of specialized features, functions, and excellences that other species ha…

AFAIK human natural niche was persistence hunting. Due to our body shape and ability to sweat, we can outrun prey species in the long run. That's how we're engineered, by natural selection in Ice Age Africa. Persistent trekkers that can throw sticks and stones. Later, we domesticated dogs and other species, then made more and more advanced technologies. But at it's core? Our niche was that.

I'm pretty sure that humans are apex persistence hunters - we can run any animal to death, not just prey species. It's a brutally effective adaptation. It's the greatest weapon we had until fire.

Even fat modern lazy humans have it in them - kick in survival mode brain chemistry and enough luck to keep chasing a deer's trail for days, the deer will die of exhaustion before the human.

Re: Why are our brains shrinking?

#83

Post by elihu »

> Yuval Noah Harari, an Israeli historian and a professor at the Hebrew University of Jerusalem, outlines how big brains are not necessarily better brains in his book Sapiens: A Brief History of Humankind. Our brains use around 25% of the calories we eat a day but account for only 2-3% of our body weight (Harari).

Interesting that our brains are so resource-intensive. It doesn't seem that surprising that natural selection would favor smaller or more efficient brains in many cases.

Re: Why are our brains shrinking?

#84

Post by scoofy »

hypertele-Xii wrote: post #79
scoofy wrote: post #47

Earlier quoted context omitted.

>they'd simplify their brain This is not how evolution works! They are not in control of their breeding. Evolution is not some intelligent agent with goals. It is like a river, responding to to the path of least resistance in reproduction. Intelligence and/or brain size not a dominant evolutionary factor unless they are specifically bread for intelligence and/or brain size. Domesticated animal's dominant evolutionary…

I think you're conflating biological evolution with evolution as a whole. Technology and culture also evolve. Just differently. Evolution is a much wider aspect of existence than mammalian genetic evolution, or even sexual evolution. I absolutely can simplify my brain consciously, by choosing to remember useful, compact things and by choosing to forget useless, complex ones. And then pass that knowledge through our c…

The subject here is biological evolution.

Re: Why are our brains shrinking?

#85

Post by notriddle »

exporectomy wrote: post #77
bobthechef wrote: post #57

Earlier quoted context omitted.

Sounds like eugenics. Heh, no thanks. Also "better" and "worse" only mean something relative to an end. I do not deny ends (I take human nature to be teleological, for example), but many "evolutionists" (i.e., those who accept a basically materialistic worldview) do deny the reality of ends (and are wholly incapable of accounting for them even if reduced to mental phenomena by virtue of having painted themselves into…

Do you have a real concern with eugenics or is it just because your culture demonizes it? We already have little bits of eugenics baked into law and culture. Why not a little bit more? It doesn't have to involve death camps.

Same reason so many people object to censorship: nobody can be trusted with that kind of power.

Re: Why are our brains shrinking?

#86

Post by guerrilla »

owenversteeg wrote: post #74

It seems like the majority of the comments are not taking into account that this trend began approximately 70,000 years ago - slightly before the various things people here are blaming such as TikTok, Google, writing, Javascript and Twitter. Cutting-edge (heh) technology 70,000 years ago was the stone blade as well as the earliest known primitive art. An interesting guide whenever you're trying to put this kind of th…

Far before civilization too, so I guess we can't blame sedentarism either.

Re: Why are our brains shrinking?

#87

Post by Factorium »

elihu wrote: post #83

> Yuval Noah Harari, an Israeli historian and a professor at the Hebrew University of Jerusalem, outlines how big brains are not necessarily better brains in his book Sapiens: A Brief History of Humankind. Our brains use around 25% of the calories we eat a day but account for only 2-3% of our body weight (Harari). Interesting that our brains are so resource-intensive. It doesn't seem that surprising that natural sele…

This is already playing out at a global level:

https://www.sciencedirect.com/science/article/abs/pii/S01602...

"There were strong negative correlations found between national IQ and three national indicators of fertility."

I think we should look on with worry that there are people with smaller brains that we are now giving unlimited resources to (food, technology, medicine), via aid and welfare programs. The dysgenic potential is immense.

Re: Why are our brains shrinking?

#88

Post by algebraically »

vlovich123 wrote: post #80
algebraically wrote: post #5

Because we are being domesticated. Domesticated animals are all dumber than their wild counterparts. Every wild animal that ends up being domesticated ends up with a smaller brain. I should rephrase and maybe say that this doesn't necessarily mean the animals get dumber but they definitely change in the process of domestication and a smaller brain is one of those adaptations. [1] > The reduced amount of white matter…

How does your argument explain the Flynn effect?

The Flynn effect is now going in the opposite direction and I don't think it was a good indicator of intelligence anyway because intelligence is more than just IQ. [1]

1: https://news.ycombinator.com/item?id=29033354

Re: Why are our brains shrinking?

#89

Post by tamaharbor »

guerrilla wrote: post #86
owenversteeg wrote: post #74

It seems like the majority of the comments are not taking into account that this trend began approximately 70,000 years ago - slightly before the various things people here are blaming such as TikTok, Google, writing, Javascript and Twitter. Cutting-edge (heh) technology 70,000 years ago was the stone blade as well as the earliest known primitive art. An interesting guide whenever you're trying to put this kind of th…

Far before civilization too, so I guess we can't blame sedentarism either.

Kind of like warming since the end of the last glacial period 10,000 years ago.

Re: Why are our brains shrinking?

#90

Post by Kye »

Factorium wrote: post #87
elihu wrote: post #83

> Yuval Noah Harari, an Israeli historian and a professor at the Hebrew University of Jerusalem, outlines how big brains are not necessarily better brains in his book Sapiens: A Brief History of Humankind. Our brains use around 25% of the calories we eat a day but account for only 2-3% of our body weight (Harari). Interesting that our brains are so resource-intensive. It doesn't seem that surprising that natural sele…

This is already playing out at a global level: https://www.sciencedirect.com/science/article/abs/pii/S01602... "There were strong negative correlations found between national IQ and three national indicators of fertility." I think we should look on with worry that there are people with smaller brains that we are now giving unlimited resources to (food, technology, medicine), via aid and welfare programs. The dysgenic…

There are so many problems with this post.

* Implying a connection between IQ and brain size

* Implying IQ is a measure of a person's worth to society

* Implying people below some magic IQ threshold that renders them unworthy are being "given" resources

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