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https://med.stanford.edu/news/all-news/2026/09/two-separate-...
Preprint of paper: https://www.biorxiv.org/content/10.1101/2025.07.02.662771v1
Original paper:
https://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
Thanks! I've changed the link above to https://www.newscientist.com/article/2589739-our-brain-evolv... from https://medicalxpress.com/news/2026-09-human-brain.html.
Seems to be based on the Stanford article: https://med.stanford.edu/news/all-news/2026/09/two-separate-...
Which is a much better article
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.
I'd imagine the science from the 80s is very dated now, no matter how good the book is.
So hindbrain is the OS kernel and forebrain the application server ?
I think more like file explorer!
Maybe more like the baseband modem in a phone?
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.
That sounds about right.
Neurosurgeon here: No
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?)
The paper title sits better with me, even as a non-expert: "Two parallel neural ectoderm progenitors contribute to the developing brain".
https://www.nature.com/articles/s41593-026-02433-7
Free preprint:
https://www.biorxiv.org/content/10.1101/2025.07.02.662771v1
I've added that link to the toptext as well. Thanks!
Ok let's give it a go!
Argument from authority. Elaborate or nobody cares.
really? conditional on them actually being neurosurgeon, I'd place a lot more stock on it than on a random headline based on their authority alone. So I, for one, care.
Argument from authority is a bad thing specifically when it's used to make incorrect claims on the basis of authority. But authority as a concept still has plenty of merit.
Correct, but an argument from authority requires certification as an authority.
Otherwise I'm free to claim I'm an authority on your moms butthole.
LOL. Hilarious
Authority is a heuristic for which claims are worthy of investigation, not determining their truth
Always be suspicious of people who don't atleast give us even a single valid sentence to construct the chain of thought that would lead to their negation or assertion.
An authority claim by virtue of itself is not worth investigating. Science doesn't work that way. Math doesn't work that way.
Exactly. Thank you.
I would leave you to contemplate the meaning of what you yourself wrote.
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...
...in a specific region, in a specific time period, immediately before the economic and then societal crash of the eastern Mediterranean that changed culture in the region forever.
The hypothesis breaks down pretty hard when you realize he just kind of handwaves away people in the rest of the world not having any kind of abrupt cut-over in the styles of recorded literature that forms the backbone of his arguments.
Are you sure about this? If you look at the ancient stories in India you can similar phenomena
Yes, Jaynes used a comprehensive approach, albeit one rooted in literature. I only threw in "Homer" as an example to be clear that "ancient civilizations" referred to bronze age and before, and that this was not the Joe Rogan kind of ancient civilizations.
I think the trouble is once your category is loosey-goosey enough it could be open-ended to the point that anything can fit it.
The fact that overall of recorded history you can find instances of any sort of interaction with something that's felt to be a voice that's independent from one's own subjectivity is open-ended to the point that it can fit the literary and cultural history of basically any civilization on Earth.
What would be more impressive is some additional specificity, any sort of evolutionary mechanism, and any sort of supporting biological data. Otherwise the thing that is being described here isn't a theory, it's barely even vibes. This is to vibes what vibes are to coherently formed thoughts.
Okay but this article is about evolution hundreds of millions of years ago.
This is pretty fuzzy and woo woo
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.
It was a successful pop-sci book when it came out, but its conclusions continue to be met with a lot of skepticism today.
It's also explored in Neal Stephenson's "Snow Crash", which I assume many here have read. Interesting ideas that are probably more at home in fiction.
And Iam McGilchrist in The Master and His Emissary nearly 20 years after Stephenson.
https://en.wikipedia.org/wiki/The_Master_and_His_Emissary
Not relevant to the article.
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, but declaring 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.
Uh, no.
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.
That would imply a biological change in all humans in the last ~3000 years after humans had already dispersed across the entire globe?
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.
"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]
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
While worth understanding, it's a completely different topic from the article.
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.
It might explain ADHD.
Might it? I’m not sure I’m following you. Just because the cerebellum is involved?
Its a joke. You know they say ADHD types made great hunters thousands of years ago, because they can hyperfocus on that gazelle while constantly keeping their head on a swivel.
A little misleading when they mention 'our' brains, yet the study outlines that even acorn worms have the same structure.
this is not the claim made by the researchers generating this paper.
this is thier claim :
“We’ve shown for the first time that the front of the brain arises from a totally different progenitor cell than the back of the brain,” said Kyle Loh, PhD, associate professor of developmental biology. “Our discovery means that we can now grow neurons from the back of the brain, the hindbrain, in a petri dish and study their functions.”
in translation, the two regions of the brain develop from different expressive states of the progenitor populations. the problem was difficulty culturing cerebellar neurons, due to a unrecognized disparity in genetic expressivity. the neurons were being manipulated as if they were running the same config.sys, and that was not the case. this work elucidates that fact and recognizes it as essential, to invitro culture of "hindbrain" neurons.
The findings were published in Nature Neuroscience Sept. 18. Loh is the senior author. Graduate students Carolyn Dundes and Rayyan Jokhai are co-first authors of the research.
https://www.nature.com/articles/s41593-026-02433-7
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.
0. https://www.sciencefocus.com/the-human-body/the-lizard-brain...