• mateomaui@reddthat.comOP
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    10 months ago

    You mean other than being completely factually wrong?

    Brain size hasn’t been historically limited by the size of the birth canal, it doesn’t work like that, most growth takes place after birth. The fact that some children develop faster in the womb and require a c-section doesn’t make it true either.

    The context is that he’s replying to a known pusher of eugenics. It’s not completely apparent in the post Elon replied to, but if you see enough of that user’s posts it becomes apparent.

    edit: it’s also worth mentioning that sometimes a larger child is simply due to genetics from one parent. I know many very tall, large people whose mothers are very tiny, petite people. It could be considered a miracle when the birth happens naturally in those cases, but doesn’t have anything to do with the child having a larger brain. They’re just generally relatively larger than their mother.

    • Sacha@lemmy.world
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      10 months ago

      My brother is a 6ft+ white man who married a Mexican woman that’s barely 5ft tall. She wanted to do a natural birth for her first son, but he was over 9lbs and was actually tearing her apart. The pain killers weren’t working, she had a bunch of infections, they had to take a vacuum to get him out and she didn’t get better for at least a year.

      She had another two sons with him, the second was 9.6 lbs. The third was 8lbs. They were both c-cection because she wasn’t going to go through natural births again.

      (And yes, all 3 boys are much taller than their peers, they all inherited my brother’s tall gene the oldest is about 15 now and nearing 6ft)

      They are normal kids despite their sizes.

      • mateomaui@reddthat.comOP
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        10 months ago

        One of my best friends in college towered over me and his mom barely came up to my chin. His dad wasn’t even a tall guy either, he just inherited some recessive genes or something. It was a pretty usual thing for him and his mom to be standing side by side and she’d say something out loud like “I have no idea how you ever came out of me.”

    • CitizenKong@lemmy.world
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      10 months ago

      Also, our heads are still able to squish together as babies, the bones only solidifying after birth, precisely to get past the birth canal.

      • mateomaui@reddthat.comOP
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        10 months ago

        Yes, the soft cranial plates and sutures specifically allow for it, which unfortunately can result in brain damage if forceps are used to pull a larger kid out. I know of at least one case where a child never spoke until they eventually got treatments from a craniosacral therapist, and one day just straight asked for a glass of water to the total shock of the parents. They had been learning things normally, but cranial pressure affected the area responsible for speech. Which is one reason why we should be thankful c-sections are a safe option, instead of some conservatives saying people who get them aren’t technically mothers.

    • Zoboomafoo@slrpnk.net
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      10 months ago

      If brain size means nothing, then why have humans evolved larger brains over time?

      Wouldn’t the increased risk of death during birth for large heads lead to a reduction in brain size over time?

      And lastly, why are you being a dick about it?

      • mateomaui@reddthat.comOP
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        10 months ago

        No one said brain size doesn’t mean anything, although there is no documented correlation between brain size and intelligence, and since we don’t use most of our brains anyway, more volume mostly equals more unused volume.

        What was said is that historically brain size wasn’t determined by the size of the birth canal, because most growth happens after birth anyway, and that’s the main functional reason for the skull to still be soft and need more protection than later. Else we would come out with fully formed brains and fully formed, hardened skulls.

        Which should be obvious to you if you compare the size of any infant’s head with any adult’s head.

        And why are you so sensitive about being asked what’s wrong with it other than it being completely factually wrong?

        • Zoboomafoo@slrpnk.net
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          10 months ago

          Here’s your correlation.

          And you might want to double check that “don’t use most of our brains” part

          Also, I never mentioned intelligence, that was all you.

          I’ll break it down:

          Before c-sections:

          1. Head size is genetic

          2. Some babies have heads too large for birth

          3. Those babies die, and don’t pass on their genes

          Add c-section technology:

          1. Head size is genetic

          2. Some babies have heads too large for birth

          3. Those babies get c-sections and live

          4. Big head babies pass on their big head genes to the next generation

          • mateomaui@reddthat.comOP
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            10 months ago

            Your add-on breakdown wasn’t necessary, you’re not informing me of anything, I already provided the relevant info in other replies.

            You didn’t mention intelligence, but that’s the only logical conclusion to draw from suggesting larger brains in our current population is an advantage or important, or “means nothing”/anything.

            If you want to get on the eugenics train, Elon is available for discussion.

            • Zoboomafoo@slrpnk.net
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              10 months ago

              You’re putting words in my mouth, I’m only talking about the Homo genus’s increase in brain size due to evolution, and how c-sections will affect that over time

              I’m not commenting on intelligence variation in Homo sapiens

              • mateomaui@reddthat.comOP
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                10 months ago

                And plenty of people smarter than you have debunked the notion that the size of the birth canal historically was significant to the size of brains, since most children experience most of their size increase after being born. That more children are saved via c-sections because they’re larger from earlier development or because they’re just relatively larger than their mother isn’t statistically significant for brain size or the practical results of that increase.

                This has been covered in other replies and it’s obvious you’re being obtuse about it, so I’m ending the conversation from my end here. Enjoy arguing with someone else about it.

          • mateomaui@reddthat.comOP
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            10 months ago

            Correlation within the current human species only, there was development other than just size from ancient history that you aren’t accounting for.

            If you’re talking about the 10% myth, I wasn’t referring to that, but there are documented cases including at least one person missing most of their brain from a long-term condition where the brain filled with fluid, leaving a thin perimeter of brain matter, and they were otherwise still fully functional except for weakness in one leg. A total mystery, and provided proof that the brain can rewire itself and doesn’t need most of its volume to function correctly, and suggested evidence that the brain uses what’s needed, but that most of it isn’t required.

            edit:

            https://qz.com/722614/a-civil-servant-missing-most-of-his-brain-challenges-our-most-basic-theories-of-consciousness

            Note that while it does say he was of below average intelligence but not mentally disabled, that’s not the point. The point in me providing this here is that losing most of his brain over time didn’t affect the intelligence he naturally had, or affect other brain function, so he was fully functioning and normal as far as anyone was concerned until he went to check what was going on with his leg. Providing proof that most of the brain probably isn’t needed, and possibly redundant to compensate for loss.

            • Remmock@kbin.social
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              10 months ago

              A single case is not proof and you should know this. It’s an outlier. A substantial majority of people with brain damage have affected function in some form or another. If you can show a statistically significant number of cases I may consider your evidence.

              More specifically to your example, they showed an impact to their functioning. In addition a neurosurgeon commented: “The patient was not missing brain, but because the skull is a fixed volume, it cannot expand to accommodate increased pressures so the brain instead gets pushed outwards by the fluid and compressed.”

              • mateomaui@reddthat.comOP
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                10 months ago

                A single case is not proof and you should know this. It’s an outlier. A substantial majority of people with brain damage have affected function in some form or another.

                No shit, not sure what part of “documented cases including at least one person” you didn’t understand, but I only provided the most extreme example. Further, most people with brain damage didn’t experienced it from a condition that slowly happened over time where the brain could adapt. Most happen from malformation where the brain was never in a healthy state to begin with, or from immediate traumatic injury where it wouldn’t have had the time to adapt to it, and nobody expects that it would.

                Also, I said “provided proof that the brain can rewire itself”, not that it will. There is a difference between what I said and your interpretation of my statement.

                More specifically to your example, they showed an impact to their functioning.

                Other than the leg symptoms, not according to the article I linked:

                In theory, the frontal, parietal, temporal, and occipital lobes in the brain control motion, sensibility, language, vision, audition, and emotional and cognitive functions. But those these regions were all reduced in the Frenchman. He did not, however, suffer significant mental effects, suggesting that, if an injury occurs slowly over time, the brain can adapt to survive despite major damage in these regions.

                It says the regions of the brain were reduced, but not his function, feel free to quote the exact phrases that say otherwise in significant fashion where he didn’t present as normal other than the leg issue.

                or from the Lancet article:

                https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(07)61127-1/fulltext

                The leg weakness improved partly after neuroendoscopic ventriculocisternostomy, but soon recurred; however, after a ventriculoperitoneal shunt was inserted, the findings on neurological examination became normal within a few weeks. The findings on neuropsychological testing and CT did not change.

                Which addresses the leg symptoms improving, and that his relatively normal neuropsychological results didn’t change.

                From you:

                In addition a neurosurgeon commented: “The patient was not missing brain, but because the skull is a fixed volume, it cannot expand to accommodate increased pressures so the brain instead gets pushed outwards by the fluid and compressed.”

                This quote does not appear to be found in the original article or any that are linked from it, but regardless his brain was severely impacted as you can see from the brain images in the Lancet entry, yet he had no significant effects from it. Whether the brain was missing or quished into an tiny area makes no difference at all, he should have had severe symptoms but didn’t.

                If you can show a statistically significant number of cases I may consider your evidence.

                Fuck off. I don’t care if you’re willing to consider anything, I’m not writing a dissertation here. I’m not going to go around and build a portfolio to make you happy. Go try being amazed at something that the best neuroscientists don’t understand.