115 points Jimmc414 17 hours ago 64 comments
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
Jimmc414 17 hours ago | parent
https://www.nature.com/articles/s41593-026-02433-7 (paywall)
New Scientist Article:
https://www.newscientist.com/article/2589739-our-brain-evolv...
dang 13 hours ago | parent
____tom____ 17 hours ago | parent
amirmc 11 hours ago | parent
jschveibinz 17 hours ago | parent
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.
esperent 12 hours ago | parent
adammarples 16 minutes ago | parent
srean 16 hours ago | parent
ChennakeshavaG 16 hours ago | parent
fph 15 hours ago | parent
saltcured 15 hours ago | parent
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.
srean 15 hours ago | parent
colinbrain 13 hours ago | parent
dang 13 hours ago | parent
(Perhaps the updated title is less objectionable?)
ceroxylon 12 hours ago | parent
elendilm 12 hours ago | parent
ajkjk 12 hours ago | parent
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.
someguynamedq 12 hours ago | parent
elendilm 12 hours ago | parent
An authority claim by virtue of itself is not worth investigating. Science doesn't work that way. Math doesn't work that way.
elendilm 11 hours ago | parent
Exactly. Thank you.
> I'd place a lot more stock on it than on a random headline based on their authority alone. So I, for one, care.
I would leave you to contemplate the meaning of what you yourself wrote.
ajkjk 7 hours ago | parent
thin_carapace 6 hours ago | parent
carefree-bob 13 hours ago | parent
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...
crooked-v 12 hours ago | parent
...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.
ViktorRay 12 hours ago | parent
carefree-bob 12 hours ago | parent
glenstein 11 hours ago | parent
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.
ProjectArcturis 12 hours ago | parent
someguynamedq 12 hours ago | parent
plusfour 10 hours ago | parent
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.
general_reveal 12 hours ago | parent
The thing you are referencing is actually describing the alleged Holy Spirit entering the world:
(With a little help from AI, don’t kill me)
In Christian pneumatology (the study of the Holy Spirit), there is a similar paradigm shift between the ancient world and the New Testament. In the Old Covenant, God's presence was primarily external (pillars of fire, the Ark of the Covenant, stone tablets). With Pentecost and the Holy Spirit, God's presence moves inside human believers ("a new heart... and a new spirit within you," Ezekiel 36:26; 1 Corinthians 6:19).
Development of Conscience: The transition from external command-driven behavior to an internal moral compass echoes the New Testament promise that God's law would be written directly onto human hearts and minds (Jeremiah 31:33).
—-
The change Julian Jaynes observes was actually divinely promised, interesting that it can be measured.
Further, the original study that sees the merging of the two parts of the brain would also fit the Holy Spirit providing reconciliation of how your brain is even wired after it was imparted onto the world. This was all promised , if you believe Christ. It’s even more reassuring that that this biological reconciliation happened around when Christ died , plus or minus a thousand years.
vor_ 12 hours ago | parent
dinobones 12 hours ago | parent
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).
glenstein 11 hours ago | parent
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.
hn_throwaway_99 10 hours ago | parent
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.
glenstein 10 hours ago | parent
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.
jibal 1 hour ago | parent
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.
nkrisc 11 hours ago | parent
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.
mitxela 8 hours ago | parent
It's probably BS though.
drdaeman 6 hours ago | parent
- 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.
spragl 40 minutes ago | parent
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.
alexpotato 12 hours ago | parent
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
Dylan16807 10 hours ago | parent
throwaway17_17 5 hours ago | parent
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.
reliablereason 12 hours ago | parent
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.
Chance-Device 12 hours ago | parent
hbarka 12 hours ago | parent
Chance-Device 12 hours ago | parent
hbarka 12 hours ago | parent
networkOne 11 hours ago | parent
rolph 11 hours ago | parent
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.
afpx 6 hours ago | parent
adolph 9 hours ago | parent
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.
Edit/Append: Something I will keep an eye out for is how this knowledge changes the understanding of cephalopod brain dev/func. If hemichordates were evolutionarily later than protostomes like an octopus, what will that mean for the types of neural cells available for them? If octopus neurology is more like "forebrain and midbrain—which are both aNE-derived lineages," then does that mean that the "posterior neural ectoderm (pNE)" is evolutionarily later?
0. https://www.sciencefocus.com/the-human-body/the-lizard-brain...