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Comment by suddenlybananas | Hacker News Reader

Sure, but is the difference between being 2 and 4 really that profound? It's not like the memories that are lost are just of the womb.

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Have you spent a lot of time with children?

My 2 year old went on a mental breakdown of a temper tantrum last night because she saw an apple on the tv, decided it meant she wanted an apple, and couldn't understand why she could not have an apple despite seeing one on the tv just then! A toddler is still trying to understand how reality itself works.

A 4 year old knows that jumping off of the stairs onto tile is going to hurt. A 4 year old understands the apple on the tv is an apple on the tv and is not a physical apple in the house.

They are so far apart.

Obviously a 4 year old is much more together than a 2 year old. But we're talking about a fundamental difference so great that no memories can be preserved. That's a high bar.

Uhhh yes.

Age 2: Can point to their own body parts; hold something in one hand while doing something with the other hand

Age 4: Changes behavior based on where you are; can draw a person with more than 3 distinct body parts

There's a huuuge amount of learning that happens through this period. Your brain is learning things like 3-dimensional space, temperatures exist and I don't like some of them, I-have-two-arms, things fall when dropped, I must engage my big toe to stay upright while walking, other people appear to have feelings, other people appear to believe that I appear to have feelings.

And in any case, the difference between 2 and 4 is only relevant to the question of whether a 4 year old can remember being 2, not what this article is about, which is adults not remembering being <4.

>There's a huuuge amount of learning that happens through this period. Your brain is learning things like 3-dimensional space, temperatures exist and I don't like some of them, I-have-two-arms, things fall when dropped, I must engage my big toe to stay upright while walking, other people appear to have feelings, other people appear to believe that I appear to have feelings.

Many of those things are completely innate. Walking for example, while people use the word "learn" in casual speech, is something that is innate. I just don't think the original comment is well-grounded in what we know about infant's cognition. And in any case, a 2 year old definitely understands 3D space.

... walking absolutely must be learned... They will automatically learn it without explicit teaching but indeed it must be learned. A child prevented from standing or walking for 5 years and then stood on their feet for the first time will not be able to walk.

That is simply not true. There are many cultures which greatly restrict infants' ability to move (e.g. traditional rural communities in Northern China or the Ache in Paraguay) and the children in these communities still learn how to walk. Not only that, but the basic neural mechanisms that are used in walking are innately specified (central pattern generators), not learnt (https://www.sciencedirect.com/science/article/abs/pii/S09594...). Now, there is a degree of "fine-tuning" that is learnt that makes the walking more fluent and precise, but the basic principles of walking are innate.

One only needs to see a foal walking less than an hour after birth to be convinced of this.

Part of the problem is that humans are born so premature that people confuse natural maturation with learning. Just as we don't learn puberty, we don't learn how to walk.

Which cultures completely restrict their infants from attempting to walk?

Did you read the paper you linked? It describes all the immense amount of learning that actually happens: https://art.torvergata.it/retrieve/e291c0d4-b584-cddb-e053-3...

> One only needs to see a foal walking less than an hour after birth to be convinced of this.

Have you actually seen a foal walking? They are very visibly learning how to do it!

>Which cultures completely restrict their infants from attempting to walk?

The ones I mentioned in my comment.

>Did you read the paper you linked? It describes all the immense amount of learning that actually happens.

Again, as I said, there is a degree of fine-tuning but the core mechanisms are innate.

Some examples:

> In particular, the core premotor components of locomotor circuitry mainly derive from a set of embryonic interneurons that are remarkably conserved across different species

>Detailed EMG recordings in chick embryos during the final week of incubation showed that the profiles of EMG activity during repetitive limb movements resemble those of locomotion at hatching

> In addition, human fetuses exhibit a rich repertoire of leg movements that includes single leg kicks, symmetrical double legs kicks, and symmetrical inter-limb alternation with variable phase.

I don't think you read the article, or else you think that "development" means learning.

>Have you actually seen a foal walking? They are very visibly learning how to do it!

They can walk right away, but they get better at it. It's innate, but you can fine-tune it. Like I said.

Another (impressive) example of an animal innately walking, this time to avoid predators immediately after hatching https://www.youtube.com/watch?v=B3OjfK0t1XM

I think your definition of innate is counter to the common definition of innate. The common definition of innate is that there is no thought behind full understanding and capacity to perform- for example, snakes do not generally need to learn how to move without legs or how to open the mouth large enough to consume big food. There isn’t a try/fail cycle while they understand the capacities of their body. I fed my pet snake a baby quail for the first time in its life and it clearly had to learn how to eat it (tried and spat out the leg, wing, etc) even though the core mechanism of big mouth big swallow is there was clearly innate in it. Just because there is a core mechanism to walk existing in babies doesn’t mean the baby doesn’t still need to learn how to perform the behavior voluntarily, on command, consciously according to their own will.

What you just described for the baby applies equally to the snake. It's obviously difficult to neatly segment things into innate and non-innate, but the idea that walking is a matter of maturation rather than "learning" is the mainstream view among scientists and has been for a century.

Again, I conceded that you have to "fine-tune" to get good at walking. But the contrast that with say, playing golf. That's something that categorically has to be learnt, we don't see fetus practicing their drive in utero.

They do not keep them tied till they are 5 years old.

That's just being pedantic. They also don't "learn" to walk if their legs are cut off.

No, that is actually exactly what I was describing. If it was innate, they wouldn't need to trial and error their way (i.e. learn) to proficiency. But indeed they do.

Your analogy was puberty, which in fact happens with development regardless of trial and error (i.e. learning).

The two developmental processes are clearly distinct. The distinction is that one is a process of learning and the other is not.

I'm talking about being able to walk, you're talking about being proficient. I've said repeatedly that fine-tuning to get better is not incompatible with innateness.

A child totally prevented from standing for 5 years and then stood on their feet will not walk at all.

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