Ask HN: Do newborns have a standardized brain structure?
To be more exact I was just wondering that when a child is born does their brain have distinct differences in its neural network structures when compared to other newborns—assuming they grow up to be neurotypical people, so not accounting for any genetic predisposition to developing mental illness.
What I really want to know though is when the brain starts responding to its environment and begins evolving as a result of the input it receives from various senses, does it do so from basis that’s shared with all other newborns or is every person truly unique at birth.
20 comments
[ 22.5 ms ] story [ 53.6 ms ] threadMaternal stress, which the fetus can sense through hormones that cross the placental barrier, is also known to affect development before birth.
"Taste of kale makes unborn babies grimace, finds research"
https://www.theguardian.com/science/2022/sep/22/taste-of-kal...
Babies respond to “inputs” in the womb. The environmental factors that affect brain development (not “evolution”) include maternal hormones, nutrition, drugs and alcohol, even sounds.
The obvious (and prevailing) perspective is both.
Intellectual and psychological traits have some genetic predisposition, yet we should never discount the general adaptability of all minds.
Want science proofs? Consider how twins who grow up apart are strikingly similar, and consider how these examples might diverge from your own (random) characteristics.
It’s an interesting question to think about but I think any answer is going to have a considerable degree of speculation since we don’t fully understand how the brain works and why it’s the way it is.
Googling “twins raised apart” provides a handful of stories.
One of the more interesting is the story of the Korean twins having a “huge IQ difference”, the lower experienced less stability in her upbringing. Otherwise their personalities were the same. This is interesting as twins raised together often have different personalities, probably drawn from their (possibly subconscious) intentions not to be too similar.
https://www.mcgill.ca/oss/article/general-science/identical-...
The extent to which the wiring is identical, and how much of our intelligence and ability to learn comes "hard wired" is one of the Big Open Questions in neuroscience / cognitive science.
[1] I think there are a few exceptions. <IIRC> If some area is broken sometimes another part may replace the functionality with a lower accuracy. And for example if you are blind, then the visual area may help to interpret the Braille code in your fingerprints. </IIRC>
It's one of those topics that becomes more mindblowing the more you know about it, or related topics such as AI/ML research.
Random examples:
How does sexual attraction get encoded in the brain? Think about how complex and subtle the selection criteria has to be to reliably[1] pick out "same species", but not "same sex of the same species". The distinguishing attributes are subtle, such as slight changes of the fat distribution of the face, and a couple of body ratios[2]. But to identify body ratios, you need to be able to identify bodies, ratios, and have that entire mapping from the visual cortex all the way through to the arousal centre of your brain be learned in a way that is consistent with something encoded in your genetics that was laid down in your neurons before birth, at a time when you had not yet seen anything, let alone male or female humans!
The other one that blows my mind is how terrestrial animals are afraid of heights. This has been studied at length, and despite this the exact mechanism is not perfectly understood. Even babies are afraid of crawling over a ledge. But think about it: what is a ledge? It's not just "an edge", it has to have a certain spatial orientation to be dangerous and scary! This instinct is baked into every brain, but its trigger is a complex combination of head angle, gaze angle, depth perception, and 3D geometry! Even animals that don't have stereoscopic vision are able to identify a dropoff and be afraid of it.
To me the most amazing is how all quadruped grazing animals are able to walk or even run from birth. That's a staggering level of neural training pre-baked before birth! Vision, proprioception, muscle control, everything pre-trained to the point of some animals able to outrun a cheetah on rough terrain mere days after plopping out of their mother! Go ask Boston Dynamics how hard a problem this is to solve...
[1] Actually, the failure modes are educational! Bestiality and furry tendencies indicate that this neural encoding is based on a shared set of traits with all mammals, but with species-specific aspects. Clearly the filters are good, but not perfect.
[2] Apparently just some specific curves suffice: https://www.etsy.com/au/listing/673314609/sexy-lovers-art-pr...
No.
Genetic diversity due to isolation of cultures in their environments over the eons has made this impossible.
The differences between unrelated newborns would be both genetic & environmental, compared to the identical genetics and nearly identical environments of the twins.
From which point all would begin to diverge further.
In the womb.
Why do you ask?