Having watched my kids grow up while observing this effect, I've come to the conclusion that kids' nervous systems aren't as sensitive as adults. That, or they are just brain damaged. :)
Ignorance is an interesting question. Does it not bother them because they haven't been conditioned that it bothers them? It makes me think of pain. The anxiety of anticipating pain and of what experiencing the pain will be like is often as or more significant than the pain itself and can cause significant impact on the sufferer's life irrespective of the pain itself. Dogs, on the other hand, do not anticipate the pain, so, even when they hurt, it doesn't have the same impact on their lives.
That's a long way around to get to this: maybe it's not the discomfort of the cold itself that is highly uncomfortable, but the anxiety of the anticipation of what the cold will be like, and that is not something kids have the experience to, well, experience.
I thought about this about falling. Kids do fall all the time, but instead of anticipating failure, they go all in for "success" (whatever success can be for a kid). More momentum is created, diffusing energy in a smoother way. The mindset shutting down the brain for the "negative" aspects of the situation, because it came from a desire not from fear.
I have similar thoughts when playing music, whenever I get a nice sound, I don't feel pain or exhaustion, but every time I fail it suddenly become tiresome.
Ha, just yesterday I went in the pool with my 3 year old. I was freezing and cursing (not in front of him of course) and he was as happy and active as on any summer pool day (I'm in the southern hemisphere).
Ignorance is an interesting question. Does it not bother them because they haven't been conditioned that it bothers them? It makes me think of pain. The anxiety of anticipating pain and of what experiencing the pain will be like is often as or more significant than the pain itself and can cause significant impact on the sufferer's life irrespective of the pain itself. Dogs, on the other hand, do not anticipate the pain, so, even when they hurt, it doesn't have the same impact on their lives.
That's a long way around to get to this: maybe it's not the discomfort of the cold itself that is highly uncomfortable, but the anxiety of the anticipation of what the cold will be like, and that is not something kids have the experience to, well, experience.