For those interested in brain evolution and practical neuroscience/human behavior:
Carl Sagan's books "Broca's Brain" and "The Dragons of Eden" from the 70's-80's are good initial reads on brain composition and evolution. The Sapolsky lectures and books are also great resources.
The comments in the other post on this topic had an article which slammed Sagan's book for being outdated and espousing debunked triune Brian theory. The article was called "your brain is not an onion with a lizard inside".
It's a crude analogy, but I would say the hindbrain is more like the system management co-processor or controller that tends to low-level hardware features.
The forebrain is the main processor. It does all the stuff you think of from OS to application, and has some ability to monitor and even interfere in the system management co-processor.
Whether either of these things have interesting internal structure and functional decomposition is left unaddressed. This observation about the progenitor cells is a bit like seeing the BOM that says they come from different suppliers.
I think it's also a bit of guesswork to try to reason out the evolutionary history. I.e. was either unit "in the market" longer and useful on its own, versus essentially complementary parts that just happen to have a divided supply chain! Intuition about evolutionary processes and life makes it really easy to assume the hindbrain is an older, legacy system that existed independently or with other long-lost companion units.
Just for context: parent comment was posted when the submission title was "Human brain is two separate organs, research finds". We've since changed it.
(Perhaps the updated title is less objectionable?)
There was a book in the 1970s called "The Origin of Consciousness in the Breakdown of the Bicameral Mind" by Julian Jaynes, where he argued that ancient civilizations -- and he used examples from Homer -- lacked the current modern sense of self-consciousness. If you look at their behavior, they interact with some external divine voice that drives their actions, whereas if you read modern literature you see people being driven by an inner voice which they associate with themselves.
This shift from the "bicameral mentality" of the external voice to the modern mentality of the inner voice was hypothesized by Jaynes to be rooted in some biological changes in the brain. At the time there was split brain research that showed these two parts of the brain function independently almost as two different minds in the same skull. See this 2007 survey: https://www.researchgate.net/publication/6323702_The_bicamer...
It's one of the craziest, most interesting books i've read on the mind. He makes a much stronger argument than can be summarized in a comment. He takes you on a wild journey you are surprisingly ill-equipped for.
And as this complexity develops, there is the first unsureness, the first need for personal gods to intercede with the higher gods, who seem to be receding into the heavens where in one brief millennium they will have disappeared.
Also, that study is extremely dubious/barring on fan-fiction.
Homer (if he was even a person) recited oral epic poetry (that we've lost most of) and we've written down an extremely lossy version of it.
Why should we take any of the mythical character's interactions with mythical gods as any insight for the brains of real humans???
It'd be like year 4000 historians citing World of Warcraft claiming the Lich King is a very obvious example that humans lack an internal monologue because he was not able to distinguish his own motives/actions between Ner'zhul/Arthas (both spiritual entities inhabiting the "Lich King" body).
I mean I definitely disagree with the book's argument, and you're right that it's making a different argument than the article, but I think straight up declaring it irrelevant is coming in way too hot. It's also an argument for a merging of separate mental structures that's sourcing the change in an event from recent natural history.
Again, I don't agree with the book's argument, declari g an argument proposing a similar convergence on the basis of entirely different reasons to be not even mentionable in response to the article is just getting way too overzealous with comment section policing.
The premise (and this is how the GP comment put it) was that humans around Homer's time had fundamentally different brain structures, and that differences in poetry and thinking processes could be explained by looking at how brains changed over the last few thousand years.
That's not "overzealous comment section policing". It's rejecting a premise that is completely infeasible with everything we know about human evolution (or relative lack thereof) during that timespan.
Uh, yes. It's overzealous because personally disagreeing with something doesn't mean that it's outside the scope of the subject matter that the article is speaking to. If anything, you're reaffirming the commonalities between the theory and what's proposed in the article because what they have in common is a proposed difference in brain structures followed by a convergence.
The fact that you disagree with the truth of the theory has literally nothing to do with whether it's on point in response to an article that's about the same subject matter. I would have hoped that me saying multiple times that I disagreed with it would have made clear already that there's more going on here than just a matter of whether you do or don't disagree with it. Declaring that it's "not overzealous" mirrors my language back at me but without attaching an actual argument to it.
What could plausibly cause that change in just a few thousand years?
I cannot see how this could be true without it following that not everyone will have this change as it is far too recent to have spread to everyone every where. Where are these people who lack it?
My read was that they were also disagreeing with it (and I personally disagree with it too for exactly the reasons you mention).
But the problem in this case isn't just that it's right or wrong, it's that it at least belongs to a related family of arguments that are fair game to explore in response to the article. Some of the best conversations take the form of knowing something is wrong but powering through the struggle of putting the why into words, and all the associated conversational branching that can happen along the way.
"too hot" and "way too overzealous" is ad hominem, and talking about comment section policing is remarkably hypocritical -- you're actually telling someone not to make certain sorts of comments, which pointing out that something is not relevant to the article doesn't do. Your "not even mentionable" is a complete fabrication -- the comment from dinobones said nothing of the sort. Your whole shtick about "getting way too overzealous with comment section policing" is a complete fabrication -- a projection of what you are doing onto a simple factual statement. And your "Uh, yes" comment below is more obnoxious trolling and attacking strawmen.
My immediate reaction to the comment about Jaynes's book and the split brain was that it's not relevant to the article, and it conflates three very different things. The comment omits the crucial fact that the split brain research was on people whose corpus collosum had been cut -- no surprise that "these two parts of the brain function independently" since they were no longer attached to each other (which is the complete opposite of what TFA is about). Jaynes's hypothesis was not related in any way to that research, and neither are related in any way to TFA. As someone else noted: "Okay but this article is about evolution hundreds of millions of years ago." -- the clear implication being that Jaynes and split brains aren't relevant. But if anyone actually dares say so, here comes the too hot overzealous comment section policeman to project his own attributes onto them.
And this is completely aside from whether Jaynes's argument is valid ... you saying multiple times that you disagree with it is also utterly irrelevant and reflects one of several fundamental errors in logic in your comments. But criticisms of your comments is not "comment section policing" -- how absurd ... and dinobones didn't even do that in simply saying that a comment wasn't relevant to the article ... only in your head was "and therefore you are not allowed to post it here". Presumably the comment was made in good faith. I can even grant the same about yours, with a bit of straining and extraordinary charity.
Not necessarily, could be a change in environment. E.g. teaching people to read by imagining a voice in their head teaches them the voice is their own.
It’s an interesting book for sure, but I had (minor, but still) issues even with the introductory premises. Just a few notes I made from the very first chapter:
- Jaynes used the term “reminiscence” in a way very different from Ballard and claimed no animal is capable of reminiscence. That was a very odd claim overall.
- Then he claimed that if we ever create a language that can express everything, metaphors won’t be possible. Which is, I think, almost obviously false, because many metaphors are constructed artistically, despite having exact terms.
- And he talks about spatialization as a primitive aspect of consciousness, but he seems to talk about relations/connectedness at best.
And so on - I misplaced my notes somewhere and only recovered a few random bits. Still, interesting reading, fun (albeit really questionable) core idea, but those papercuts were kinda off-putting for me.
His theory was that the two brain halves communicated through inner voices. Wernickes Area, on the left side, communicated with the similar area on the right side. WA is where we comprehend speech, so Jaynes theorized that was why bicameral people experienced the communication as inner voices.
The research in the new research paper is about a split between front and back of the brain. So something entirely different. That split is an old idea. Jaynes would most likely have known about it. But it wasnt part of his theory.
"You Are Two" [0] is a video that talks about what happens when the connection between the two hemispheres of the brain is severed.
If you've never seen it I HIGHLY recommend it if only to show how weird our brains actually are.
A good chaser to the above is Peter Watts talk on hive minds [1]. He was a neurology research and the author of the famous sci-fi novel Blindgsight [2]
Thank you for the link to Watts’ talk. It is a great watch and is certainly a great jumping off point for anyone writing fiction in the field.
It also could be one of the most terrifying talks I’ve ever heard, but since it is eight years old, I am going to just pretend all of the research he mentions fell through and I have nothing worry about.
Michael Levin's work is an excellent place to look for this kind of stuff.
His work around intelligence is amazing. Cellular systems and organs have intelligence capabilities far beyond the individual cells. A lot of it shows that humans can be very blind to intelligence.
His flatworm experiments are a good place to start as he followed through with things they ignored in the experiments 80 some years ago.
Clearly.. this is not some new revelation, it has been the default assumption for a very long time, probably over a hundred years.
Damage to the hind brain results in behavioural changes that are blatantly different compared to when the "newer" parts of the brain is damaged. The cerebellum literally even has a different color.
Interesting. Might explain why the cerebellum and cortex work so differently? I wonder what the two ancient nervous systems looked like at the point where they merged.
Does this help explain why the circuits that control emotional crying, which rely on connections that span the anterior, posterior and midbrain, develop?
While many comments are about brain lateralization, which this research does not address, an interesting aspect is how much it would lend credence to the "Triune Model" of the brain [0], which is generally described as discredited.
The authors limit their claims to "the longstanding question in developmental biology of how and when different regions of the central nervous system diversify from one another." So folks wanting to see a "lizard brain" in there will have to keep searching.
54 comments
[ 0.18 ms ] story [ 36.1 ms ] threadhttps://www.nature.com/articles/s41593-026-02433-7 (paywall)
New Scientist Article:
https://www.newscientist.com/article/2589739-our-brain-evolv...
https://archive.is/1CFX9
Carl Sagan's books "Broca's Brain" and "The Dragons of Eden" from the 70's-80's are good initial reads on brain composition and evolution. The Sapolsky lectures and books are also great resources.
The forebrain is the main processor. It does all the stuff you think of from OS to application, and has some ability to monitor and even interfere in the system management co-processor.
Whether either of these things have interesting internal structure and functional decomposition is left unaddressed. This observation about the progenitor cells is a bit like seeing the BOM that says they come from different suppliers.
I think it's also a bit of guesswork to try to reason out the evolutionary history. I.e. was either unit "in the market" longer and useful on its own, versus essentially complementary parts that just happen to have a divided supply chain! Intuition about evolutionary processes and life makes it really easy to assume the hindbrain is an older, legacy system that existed independently or with other long-lost companion units.
(Perhaps the updated title is less objectionable?)
https://www.nature.com/articles/s41593-026-02433-7
https://www.biorxiv.org/content/10.1101/2025.07.02.662771v1
If you are old, I have nothing at my disposal. You are on your own.
This is pretty basic. One learns this early on if he has actually built something.
> regarding the brain, is there a reason your words should be trusted over those of a brain surgeon?
You thought I had made a claim about the brain. That's interesting.
This shift from the "bicameral mentality" of the external voice to the modern mentality of the inner voice was hypothesized by Jaynes to be rooted in some biological changes in the brain. At the time there was split brain research that showed these two parts of the brain function independently almost as two different minds in the same skull. See this 2007 survey: https://www.researchgate.net/publication/6323702_The_bicamer...
And as this complexity develops, there is the first unsureness, the first need for personal gods to intercede with the higher gods, who seem to be receding into the heavens where in one brief millennium they will have disappeared.
https://en.wikipedia.org/wiki/The_Master_and_His_Emissary
Also, that study is extremely dubious/barring on fan-fiction.
Homer (if he was even a person) recited oral epic poetry (that we've lost most of) and we've written down an extremely lossy version of it.
Why should we take any of the mythical character's interactions with mythical gods as any insight for the brains of real humans???
It'd be like year 4000 historians citing World of Warcraft claiming the Lich King is a very obvious example that humans lack an internal monologue because he was not able to distinguish his own motives/actions between Ner'zhul/Arthas (both spiritual entities inhabiting the "Lich King" body).
Again, I don't agree with the book's argument, declari g an argument proposing a similar convergence on the basis of entirely different reasons to be not even mentionable in response to the article is just getting way too overzealous with comment section policing.
The premise (and this is how the GP comment put it) was that humans around Homer's time had fundamentally different brain structures, and that differences in poetry and thinking processes could be explained by looking at how brains changed over the last few thousand years.
That's not "overzealous comment section policing". It's rejecting a premise that is completely infeasible with everything we know about human evolution (or relative lack thereof) during that timespan.
The fact that you disagree with the truth of the theory has literally nothing to do with whether it's on point in response to an article that's about the same subject matter. I would have hoped that me saying multiple times that I disagreed with it would have made clear already that there's more going on here than just a matter of whether you do or don't disagree with it. Declaring that it's "not overzealous" mirrors my language back at me but without attaching an actual argument to it.
I cannot see how this could be true without it following that not everyone will have this change as it is far too recent to have spread to everyone every where. Where are these people who lack it?
But the problem in this case isn't just that it's right or wrong, it's that it at least belongs to a related family of arguments that are fair game to explore in response to the article. Some of the best conversations take the form of knowing something is wrong but powering through the struggle of putting the why into words, and all the associated conversational branching that can happen along the way.
My immediate reaction to the comment about Jaynes's book and the split brain was that it's not relevant to the article, and it conflates three very different things. The comment omits the crucial fact that the split brain research was on people whose corpus collosum had been cut -- no surprise that "these two parts of the brain function independently" since they were no longer attached to each other (which is the complete opposite of what TFA is about). Jaynes's hypothesis was not related in any way to that research, and neither are related in any way to TFA. As someone else noted: "Okay but this article is about evolution hundreds of millions of years ago." -- the clear implication being that Jaynes and split brains aren't relevant. But if anyone actually dares say so, here comes the too hot overzealous comment section policeman to project his own attributes onto them.
And this is completely aside from whether Jaynes's argument is valid ... you saying multiple times that you disagree with it is also utterly irrelevant and reflects one of several fundamental errors in logic in your comments. But criticisms of your comments is not "comment section policing" -- how absurd ... and dinobones didn't even do that in simply saying that a comment wasn't relevant to the article ... only in your head was "and therefore you are not allowed to post it here". Presumably the comment was made in good faith. I can even grant the same about yours, with a bit of straining and extraordinary charity.
I won't respond further.
That means whatever the change was would have to had occur simultaneously in separate populations all over the world within almost no time at all.
It's probably BS though.
If consciousness results from language and culture then some cultures will lack it.
- Jaynes used the term “reminiscence” in a way very different from Ballard and claimed no animal is capable of reminiscence. That was a very odd claim overall.
- Then he claimed that if we ever create a language that can express everything, metaphors won’t be possible. Which is, I think, almost obviously false, because many metaphors are constructed artistically, despite having exact terms.
- And he talks about spatialization as a primitive aspect of consciousness, but he seems to talk about relations/connectedness at best.
And so on - I misplaced my notes somewhere and only recovered a few random bits. Still, interesting reading, fun (albeit really questionable) core idea, but those papercuts were kinda off-putting for me.
The research in the new research paper is about a split between front and back of the brain. So something entirely different. That split is an old idea. Jaynes would most likely have known about it. But it wasnt part of his theory.
If you've never seen it I HIGHLY recommend it if only to show how weird our brains actually are.
A good chaser to the above is Peter Watts talk on hive minds [1]. He was a neurology research and the author of the famous sci-fi novel Blindgsight [2]
0 - https://www.youtube.com/watch?v=wfYbgdo8e-8&vl=en
1 - https://www.youtube.com/watch?v=v4uwaw_5Q3I
2 - https://amzn.to/4xD40td
It also could be one of the most terrifying talks I’ve ever heard, but since it is eight years old, I am going to just pretend all of the research he mentions fell through and I have nothing worry about.
His work around intelligence is amazing. Cellular systems and organs have intelligence capabilities far beyond the individual cells. A lot of it shows that humans can be very blind to intelligence.
His flatworm experiments are a good place to start as he followed through with things they ignored in the experiments 80 some years ago.
Damage to the hind brain results in behavioural changes that are blatantly different compared to when the "newer" parts of the brain is damaged. The cerebellum literally even has a different color.
The authors limit their claims to "the longstanding question in developmental biology of how and when different regions of the central nervous system diversify from one another." So folks wanting to see a "lizard brain" in there will have to keep searching.
0. https://www.sciencefocus.com/the-human-body/the-lizard-brain...