[algebraically]

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 suggests that domestic rabbits have a compromised information processing possibly explaining why they are more slow reacting and phlegmatic than their wild counterparts.

1: https://phys.org/news/2018-06-differences-brain-morphology-w...

[cogman10]

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.

[bobthechef]

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 have. Human intelligence can dream up an indefinite if not infinite number of functions which are "offloaded" to technology. We wear clothing and can adjust it depending on the climate which allow us to adapt to environments more than any other species. We have optical instruments which can extend our vision beyond that of any other species depending on need. We have all sorts of communication instruments which allow us a greater range of communication than any other species. We can harvest food in ways that put all other species to shame. We can outrun, fly, and swim any other animal. I could go on. Any capacity other species have we can (at least in principle) exceed with the help of technology, all thanks to human intelligence.

Assuming selection as an explanatory model, I don't see why we should expect to see that basic feature going away. Even with greater specialization in one direction or another, you still need much of that basic underlying generality.

[inawarminister]

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.

[robbedpeter]

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.

[hawk_]

> This is a very simplistic idea of what brains are for.

Or it could be that my small brain is incapable of seeing how small brain can mean dumber

[matheusmoreira]

Sounds like we need to take control of this evolutionary process and start engineering it. Just because we are no longer required to use these abilities on a daily basis doesn't mean we don't want them. Evolution can go to hell with its "pressures", humanity is supposed to get better over time, not worse.

[vlovich123]

You're making a value judgement like "better" and "worse" as if there was a clear global optimum that you can reach. Why do you assume that's the case?

Let's assume there even is a global optimum. Why do we think this global optimum would be invariant on environment? We have clear examples of species that fail to adapt to their changing environment quickly enough dying off. If you took the survivors of a change and then changed things back, those survivors might die again. That means you are fit to the environment you find yourself in. As the environment changes, you're not "better" or "worse" than someone who's more fit to a different environment.

Humanity is not getting strictly better on all stats. It's like a video game. We might tweak improve some stats and have to give up others. We are a bit more unique in that we largely optimize for the environment we create for ourselves, but that doesn't mean humans are constantly "getting better" over time. You could maybe try arguing that the human condition has improved over time due to technology, medicine, etc, but even that's an imperfect analysis because our historical record is so inaccurate.

[matheusmoreira]

Surely having sharper and more intelligent humans is an objectively better uncontroversial outcome. If there's even a chance that our environment is somehow downregulating important features such as intelligence, we must find a way to reverse that process.

[hawk_]

> Surely having sharper and more intelligent humans is an objectively better uncontroversial outcome

What if there's a level of intelligence above which humans decide not to reproduce?

[matheusmoreira]

I question the intelligence of a human species that does not reproduce.

[danwills]

Is this perhaps too focused on the individual which might not lead to the optimum for the zoomed-out / group (population-level) case?

This reminds me of a meta-system-transition where simplified versions of individual (previously independent) units can lead to a unified cooperative whole that works better at the meta-system level (similar to what led to eukaryotes or to multicellularity). It's like a sacrifice that the individuals make (of things that might have looked like intelligence in the previous context) in order to be able to work together better, and these kinds of transitions have worked out extremely well for life, so far! (I guess I am biased, being alive and everything!?)

Should humans resist the formation of human meta-systems? Human/robot meta-systems? Certainly seems like a good chance that an extremely successful meta-system could be dangerous to the rest of the regular humans!? But if it's actually better, then that's just normal (meta) evolution.

[matheusmoreira]

> Should humans resist the formation of human meta-systems? Human/robot meta-systems?

No. I'm saying humans should not lose abilities or features because of it. We should be able to live comfortable lives and still maintain peak physical and mental performance. Any changes in our nature should not go against that.

[SamoyedFurFluff]

But do you have any evidence of that? With our supposedly down regulated intelligence we’re achieving ever more and faster.

[bobthechef]

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 a metaphysical corner).

[exporectomy]

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.

[SamoyedFurFluff]

Eugenics involved horrific deprivations of human dignity for arbitrary decisions of what seemed at the time to be “self evidently good” traits that are much less self evidently good now… if the traits were even retained.

[notriddle]

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

[exporectomy]

Is that really why eugenics is demonized? That the human race (not any living individuals) is giving up its freedom to some sort of fallible authority?

I guess, like censorship, people only object to an arbitrary subset of it. People love censorship of "really bad" ideas just as they love eugenics of "really bad" genes.

Most people seem happy with asserting our authority of gene selection over animals though :P Conservationism is that. Not to mention actual selective breeding and killing of course. Perhaps we rightly believe humans truly are capable of being benevolent arbiters of who gets to reproduce and who doesn't in animals.

[The_Colonel]

> 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.

Doesn't this hold true for "dumbness" as well? Being dumb is no longer an obstacle in having a reproductive success.

I wouldn't be surprised if there was a peak in the reproduction rate bell curve around IQ 80-90.

[im3w1l]

> Our "domestication" has historically been more that we've gone from a generalist species to a specialist society.

Outsourcing violence to the police is a huge step of domestication.

[algebraically]

Good point.

[scoofy]

Whoa... whoa... let's unpack all the intense presuppositions you're packing in here:

"Domestication" is just a word for a natural evolutionary processes in a symbiotic system. The concept that "domestication" is like, actually a thing apart from evolution is a vastly more difficult idea to parse than it appears on it's face.

>Domesticated animals are all dumber than their wild counterparts.

I mean... again... there are so many things to unpack here. What do we mean by "dumb" and which parts of the brain are being used, and how their size relates to their usefulness. I think it would be extremely difficult to argue any of these claims on their face beyond: small brain -> less brain function, which is extremely spurious.

Homo neanderthalensis had notably larger brains than us, yet they did not survive. Hardly an argument for the idea of greater intelligence -> greater brain size. AFAIK, specific areas in the prefrontal cortex is the primary point of interest when it comes to intelligence, and it's a relatively small section of the brain compared, say, to the visual cortex.

https://www.discovermagazine.com/planet-earth/neanderthal-br...

Finally... the most absurd of all the ideas packed in here is that natural selection for smaller brain size would even be a thing. Human mating is openly available for study, I see little-to-no argument for this being plausible beyond some sort of idiocracy world (is this the domestication thesis you hold? I see in the article they are treated separately), which is genuinely problematic. Possibly that certain types of brain sizes are predisposed to certain behavioral patterns. However, the idea that there is even a single evolutionary pattern for billions of humans is pretty ridiculous. We don't have evolutionary islands like other animals do.

[hchasestevens]

> "Domestication" is just a word for a natural evolutionary processes in a symbiotic system. The concept that "domestication" is like, actually a thing apart from evolution is a vastly more difficult idea to parse than it appears on it's face.

In mammals, there is a well-established "domestication syndrome" with a specific proposed underlying mechanism and associated symptoms, including many observed in humans in comparison with other hominids (smaller jaws/muzzles, smaller teeth, smaller brain, greater docility). See https://www.genetics.org/content/197/3/795#skip-link for more information.

[scoofy]

The concept that some animals are able to be domesticated, generally, while other's are not, lends itself to the idea that drift toward docile qualities is probably working in the domesticator's favor, and is not an inherent quality of domestication as a concept.

The idea that we have an idea of a thing we can readily point at, does not mean that thing is the driving force behind it. It's just a post hoc argument. We can't domesticate zebras, we can domesticate horses. The idea that 'domestication' is a force, rather than a result of evolutionary pressure of a symbiotic relationship shows that the domestication can't be the driving force. It's just evolution.

I'm not arguing the concept that domestication syndrome doesn't exist. I obviously defer to these experts, I'm just arguing that the concept that free, independent humans 'domesticate themselves' is effectively nonsensical on it's face, as domestication, as such, requires symbiosis and controlled breeding, and is simply not possible for many species.

[akomtu]

Domestic animals have safe, boring and predictable environment. It's expected that they'd simplify their brain - the organ that consumes so much energy. If domesticated animals started playing chess, that would be a different story, but they spend their life mindlessly walking between a food dispenser and a litter box, taking naps in between.

[scoofy]

>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 qualities have nothing to do with the animal preferences for mating, thus brain size in fairly arbitrary, and we should suspect it to be some sort of drift, rather than rationally getting smaller.

[algebraically]

This is a good point but it does seem like people consistently select for less intelligence because less intelligent animals are more tame and easier to control.

[scoofy]

You don't have evidence for that. You presume that less intelligent animals are easier to control, but that's not at all necessarily true. The smaller brain -> less intelligence isn't even something we know.

[algebraically]

I definitely have evidence that wolves are smarter than dogs. [1][2] You're welcome to nitpick but it's obvious that wolves are smarter than dogs.

1: https://www.youtube.com/watch?v=soe-mONHGMc

2: https://www.studyfinds.org/wolves-smarter-dogs-logic/

[hypertele-Xii]

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 cultural transfer mechanisms.

[scoofy]

The subject here is biological evolution.

[kkoncevicius]

This is discussed in the article as one of the possibilities.

[algebraically]

Makes sense.

[29athrowaway]

Some signs of domestication in mammals

- Floppy or reduced ears

- Smaller brain and teeth

- Docility

- Juvenile behavior

- Depigmentation

[lordnacho]

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.

[algebraically]

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.

[jacquesm]

> and process information at the same rate we'd need to in a more wild enviornment

If anything that rate of processing has gone up, not down.

[algebraically]

And most of it has been offloaded to computers (big data, deep learning, etc). I don't think we're going to have "mentats" any time soon.

[jacquesm]

You have this backwards. We are dealing with orders of magnitude more information than we did in ancient times, and we are required to remember a good chunk of it and to be able to recall and use it at a moments notice.

Computers are a big factor in generating all of that information, even if they help process some of it the net effect is a huge surplus.

[GDC7]

> We are dealing with orders of magnitude more information than we did in ancient times, and we are required to remember a good chunk of it and to be able to recall and use it at a moments notice.

Surely you mean required, meaning you could end up embarassing yourself in front of your coworkers if you aren't able to recall that particular bit of information.

It's very different from REQUIRED, meaning that if you take a left turn instead of a right turn while running away from a predator you end up in a canyon... or the predator eats you because you have no way to escape...or both.

[algebraically]

I don't think I have it backwards. I don't remember anything or know much about the world in general terms. I just know and remember enough key phrases for google to give me the answers when I need them which requires very little cognitive effort on my part. [1]

1: https://www.psychologytoday.com/intl/blog/the-athletes-way/2...

[inawarminister]

Yes but let's say, pre-writing people needed to remember 100% of all information they needed to use - which writing people can offload to tablets and parchments.

Pre-agriculture people had it worse, they needed to remember 100% of all pertinent informations by the hunting band, which had a max amount of 50-100 people. All the predictive abilities for preys in their lands, natural disasters, medicines, rituals, etc.

It's logical that adoption of technology and farming led to lesser pressure for memory recall, at least for the median human.

[rackjack]

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.

[dymk]

It's beneficial to lower the brain's calorie intake it if it results in higher reproductive fitness. But like GP said, we have plenty of calories, more than we've had compared to the entire history of humanity. So it doesn't naturally follow that lower calorie brains are higher fitness in 2021.

[rackjack]

"Although our brains were getting bigger progressively, around 70,000 years ago they plateaued, and have been shrinking ever since."

From the article. 2021 is very recent.

The article also discusses energy usage a little under the section "Fuel".

[Fricken]

There are no guarantees civilization won't collapse. The traits that were essential for our survival in the stone age aren't things we want to abandon. I'm a big fan of redundancy.

[Robotbeat]

Beneficial how? Reduction in calories? We tend to have diseases of excess calories in the developed world now. If anything, the greater brain metabolism may actually help by burning some of those excess calories off…

[rackjack]

https://news.ycombinator.com/item?id=29033971

[playpause]

“Use it or lose it” applies in evolution, because of energy usage, but also because of complexity. More features means more things to go wrong, more options for cancers, etc.

[helge9210]

> Why is there evolutionary pressure for the brain to shrink?

Less energy demand, I guess.

[lumost]

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.

[snek_case]

I was going to say: maybe it's because we're so successful? We dominate our environment so well that we've made the world a much less threatening place, and so it's not as difficult to survive in the world anymore. Less selective pressure means we end up with a less selected population.

I don't want to turn this into a political commentary, but the modern age is an extreme example of this. You could be the kind of person who doesn't finish high school and can't keep a job, a deadbeat, but still manage to have multiple kids. Even if you don't take care of them, someone else will ensure that your kids survive. Long ago, not being able to are and provide for your kids probably meant that they died.

IMO, as we keep making the world increasingly more safe and comfortable, we might have to resort to genetic engineering. Otherwise, it might be inevitable that more and more genetic disorders will arise, just because we're able to keep people alive with all kinds of illnesses that would have been fatal before. People can argue about the ethics all they want, but it seems inevitable.

[SamoyedFurFluff]

Wouldn’t being able to retain maximal genetic diversity actually be a good thing species wide though? Because it also means we have ever bigger achievers in ever more niche but valuable roles.

[snek_case]

We can probably keep 99% of the diversity and just filter out diseases that significantly decrease quality of life.

[im3w1l]

Screening and abortion are already used to prevent serious disorders. For instance, a huge fraction of downies are aborted. But subtler things are more challenging.

[thro1]

Is there some study about brain sizes of kindergarten and free-range kids?

[helge9210]

I've read some articles about brain complexity of wolves depending on complexity of their habitat.

[FormerBandmate]

Domesticated by whom? How?

[algebraically]

It's possible for an animal to domesticate itself. This is one of the theories for how wolves were domesticated. It's not that humans did anything special to domesticate them but that wolves started hanging around humans and eating the scraps that were left over at campfires and other human habitation sites. Eventually the less fearful and tame wolves became human companions. Once people realized they could hang out with wolves they started actively breeding more tamer variants.

The same is true for humans. The process is obviously slightly more complicated because unlike wolves people have more influence on their environment but it's undeniable that humans are now domestic animals. No modern human can survive in the wilderness and this process is accelerating. We are now, for all intents and purposes, dependent on mechanical tools and technology for our continued existence. Feeding 8B people is impossible without industrial farming and agricultural techniques, e.g. Haber-Bosch. [1]

1: https://www.sciencedirect.com/topics/engineering/haber-bosch...

[tomjen3]

I did some research into this a couple years ago. There is an interesting theory that we didn't domesticate wolves, but that wolves domesticated us. For one, wolves naturally are very intelligent and pack hunters, so they could have used humans as a hunting partner. For another point, we domesticated wolves way before anything else (atleast 20000 years ago) and that makes no sense since every other animal we domesticated (goat, horse, chicken, etc) will eat pretty much anything and is only of very limited threat to us, whereas wolves are carnivores (very expensive to maintain) and extremely dangerous.

However, if wolves domesticated us as hunting partners, then this starts to make a lot more sense. We didn't need to first learn domestication on easier species, the danger was limited and our hunting would be so much more effective that it was worth the premium.

It also explains why we have the concept of werewolf and why some people have been charged with turning into wolves to be successful in hunting, but never any other animal (there are no cases of ware eagles/falcons). There is something primeval deep inside us that associates wolves with successful hunters.

I find the theory neat, I am not convinced it is true.

[algebraically]

Ya, I also don't know if it's true or not. I was just making the point that an animal can domesticate itself by changing its environment and then adapting to the new environment in a way that ends up being essentially a self imposed domestication process.

[lovecg]

By ourselves and the structures we created. Agriculture, etc.

[RedBeetDeadpool]

By society. More intelligence means more likelihood of "waking up". It takes a little bit of ignorance and blind trust to be a cooperative member of society. Once you get too smart, you no longer become useful and then you have to start hunting on your own. Not everyone can do that in today's age, so most people choose to delegate their decisions because the reward is that you get to live without having to think as much.

[amelius]

Ourselves. The conveniences we strive for.

[vmception]

The article touches on that too.

It is pretty comprehensive about a variety of going theories and doesn’t make the mistake of choosing any single one of them as the “because”.

[algebraically]

I did not read the article because I'm an armchair expert on such matters.

[quaintdev]

Relevant http://www.paulgraham.com/boss.html

[Asooka]

Hm, then shouldn't people who live in tribal societies as hunter gatherers have bigger brains still? Has anyone studied that?

[algebraically]

I don't know. That's a good question but most modern humans are essentially clones so I don't think there is going to be much difference. [1][2]

1: https://www.nationalgeographic.org/media/genetic-bottleneck/

2: https://en.m.wikipedia.org/wiki/Toba_catastrophe_theory

[misja111]

If you read the article you will find that your question is answered in there.

[vlovich123]

How does your argument explain the Flynn effect?

[algebraically]

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

[amelius]

Yes, people give away their private data for small conveniences, much like how pets give away their natural lives in wilderness for a guaranteed meal and a warm house.

[FormerBandmate]

70,000 years ago people were running around in groups of 50-200 people killing mammoths. Private data has nothing to do with this, that’s only happened in the past 20 years and there isn’t a generation that has lived their whole lives with smartphones that are adults yet. We have no idea what effect they’ll have on evolution

[iamstupidsimple]

What a bizarre comparison. Any animal would make the same 'choice'.