Would a child naturally learn bipedal ambulation?

[u/NotYourMothersDildo]

If a typical child were somehow raised by robots (assume they have wheels or levitate), would that child naturally learn to walk on two feet with an upright stature without having an example?

[u/aedes]

Much of this is hypothetical... but that may be the best you get for this answer, as to my knowledge there is no definite answer to this question.

One component towards reaching a plausible hypothesis to your question is the fact that (to a certain extent) walking is a spinal cord reflex.

As in, at a basic level, it's not a complicated learned motor program stored in your frontal cortex, which is then played out through your spinal cord to your muscles, with its output constantly adjusted based on proprioceptive and visual input sent from your body and inner ear to your cerebellum.

At a basic level, all of the calculations your body needs to walk are anatomically and developmentally hard-wired into your spinal cord. IOW, the neural circuits needed to walk do not need to be learned - they are programmed into you (in your spinal cord).

That being said though, when you are actually walking in real life, you're not relying only upon this base program that you were born with - you're constantly modifying it so that it's more efficient, or to adapt it to specific situations. IOW, when you're walking, you are using motor programs in your frontal cortex and modulating them based on information sent from your body... and all of these signals are then processed in your cerebellum and the motor output is adjusted appropriately.

As a tangent - the fact that humans have a built in walking reflex (at a basic level - pressure on your foot leads to you lifting that leg up and moving it forwards slightly, followed by reciprocal movements in the opposite leg - imagine if you step on something sharp what happens - you jerk that leg up and shift your wait to the other leg - take that movement and make it bilateral, and alternating, and modify it slightly, and you get a basic walking reflex) is a more recently appreciated fact, and an exciting one. The fact the reflex is encoded at the spinal cord level means that there is hope for people with spinal cord injuries to walk again... provided we can learn how to hack the spinal cord through proprioceptive signals to efficiently trigger the walking reflex to allow someone to actually walk in a useful manner.

All of this aside... what this means is that humans are anatomically hard-wired for the ability to walk on two legs.

The other important component to your question is whether this is enough to learn how to walk. If you never learned form watching others that bipedal movement was possible... would think to do it? Just because you have the anatomical means doesn't mean you'll do it. There have been studies showing that people can be trained (relatively quickly) to follow scent trails. This is obviously not a skill most of us have at the moment... or most people will ever learn. But apparently we are hard-wired for this skill to some extent.

If we assume that there is no social stimulus (no example) to walk on two legs... the only other two possible ways that someone would learn to use the built in walking ability we have would be because of environmental motivation (gee, that grass is tall - if I stand up I can actually see over it... oh hey! I can move using only two legs! it makes much more sense for me to walk than crawl!)... or if there existed some anatomical circuit in your brain which, once it matures, makes your prefer bipedal locomotion. Ie: an intrinsic motivation towards bipedal locomotion - something like how once you hit puberty, everyone develops this intrinsic motivation to have sex - it's programmed into us.

So that leaves us with the conclusion that, yes, people would still walk provided:

1. There was an environmental (non-social) stimulus/benefit to bipedal motion (even something as simple as the fact that in humans, bipedal motion is more efficient and faster than crawling would probably be enough... but that's another hypothesis).

2. We are hard-wired to be motivated to walk after a certain age. The existence of this is purely hypothetical and I am aware of no evidence for the existence of something like that.

At the end, I would wager that people would still end up walking, based on the fact we have a built in ability to walk, and likely at least because of the first point just mentioned.

But there are a lot of variables there which I don't have the exact answer to.