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Why are our brains shrinking?

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Re: Why are our brains shrinking?

#21

Post by cogman10 »

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…

I think the only thing I really quibble a bit with is the description of "dumber".

Our "domestication" has historically been more that we've gone from a generalist species to a specialist society. With that, things that were previously probably a boon for survival and reproduction become less so (For example, quick reaction times don't matter so much when you have a city wall to keep out predators and a backup hunting party).

My assumption is that what we've lost is more our brain matter used to sleep in trees and wake up/run from predators at all hours of the night. Stuff that's less important when you have night watchman, fires, and shelter.

It's similar to how dolphins have huge brains, but most of that is dedicated to sound processing. If dolphins learned how to make huts, farm fish, and fight off predators I'd imagine the part of their brain dedicated to processing sound would start to shrink as there isn't the evolutionary pressure to keep it around.

Sort of like how humans might be evolving towards color blindness because being able to tell the difference between red and green doesn't necessarily increase our ability to have children. That might lead to weird changes in our eyes and brains that could shrink them but wouldn't necessarily mean those humans are any dumber than their predecessors.

Re: Why are our brains shrinking?

#22

Post by diag »

lame-robot-hoax wrote: post #8
golly_ned wrote: post #3

.

“Although our brains were getting bigger progressively, around 70,000 years ago they plateaued, and have been shrinking ever since.” TIL TikTok existed 70,000 years ago.

Come on, give them a chance to make fun of the things the youths enjoy

Re: Why are our brains shrinking?

#23

Post by algebraically »

cogman10 wrote: post #21
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…

I think the only thing I really quibble a bit with is the description of "dumber". Our "domestication" has historically been more that we've gone from a generalist species to a specialist society. With that, things that were previously probably a boon for survival and reproduction become less so (For example, quick reaction times don't matter so much when you have a city wall to keep out predators and a backup huntin…

Good point.

Re: Why are our brains shrinking?

#24

Post by lordnacho »

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…

Why is there evolutionary pressure for the brain to shrink? We seem to have enough calories to feed our brains, and we're not beholden to some master species that needs to economize.

Re: Why are our brains shrinking?

#25

Post by FredPret »

MaxGanzII wrote: post #17

Whales have brains which physically are much, much larger than a human brain; size does not directly equate to intelligence. Note also brains are extremely expensive, physiologically, to maintain. It may simply be we are evolving to be more efficient.

Maybe whales are brilliant

Re: Why are our brains shrinking?

#27

Post by dcolkitt »

chrisco255 wrote: post #6
aaaaaaaaaaab wrote: post #2

Easy: we've offloaded some of our information storage to external media, i.e. writing.

From the article it indicates this shrinkage began 70K years ago, or 65K years before writing. In addition, vast majority of the population didn't know how to read or write until 100-150 years ago.

Maybe it’s just language in general. If I’m in a tribe with 100 people, and we all know to talk, not everyone needs to remember every single thing you might ever need. If you forget something, you can ask around, and probably someone remembers.

Re: Why are our brains shrinking?

#28

Post by Shorel »

chrisco255 wrote: post #6
aaaaaaaaaaab wrote: post #2

Easy: we've offloaded some of our information storage to external media, i.e. writing.

From the article it indicates this shrinkage began 70K years ago, or 65K years before writing. In addition, vast majority of the population didn't know how to read or write until 100-150 years ago.

But memorizing oral history surely was a thing back there.

A single narrative for all things is probably simpler than having to figure everything out every lifetime, like octopuses do.

Re: Why are our brains shrinking?

#29

Post by rackjack »

lordnacho wrote: post #24
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…

Why is there evolutionary pressure for the brain to shrink? We seem to have enough calories to feed our brains, and we're not beholden to some master species that needs to economize.

The brain itself is the evolutionary pressure. It is often repeated that the brain takes ~20% of our body's energy despite being ~2% of our body's mass. If there is no need to have a brain so large (due to a lack of predators) it is beneficial to shrink it.

Re: Why are our brains shrinking?

#30

Post by algebraically »

lordnacho wrote: post #24
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…

Why is there evolutionary pressure for the brain to shrink? We seem to have enough calories to feed our brains, and we're not beholden to some master species that needs to economize.

Because we no longer need to run away from predators and process information at the same rate we'd need to in a more wild enviornment. The survival pressures of our ancestral environment are no longer relevant. We've essentially destroyed and driven to extinction every other predator on the planet and now the only selective pressure is adaptation to the human created environment which is much nicer and simpler than the wilderness we came from. Simpler and safer environments make simpler brains and that's my best guess at why our brains are shrinking but I'm just an armchair scientist so it's better to ask the experts. The only remaining selective pressure is basically human predators, a.k.a. sociopaths.
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