I have a kiddo whose "why phase" is in full swing and I am not actually confident that it's motivated by curiosity. It's also not the most efficient way to learn things, or even the most efficient simple way (that'd probably be something like "tell me stuff about $TOPIC"), nor is it obviously geared at that goal.
In particular, my kid (I don't know how common this is) will typically formulate his questions by re-grammatizing whatever statement was most recently made in his vicinity ("it's a nice day" "why is it a nice day?" "because it's a good temperature" "why is it a good temperature?"). This will sure keep the conversation going, but:
This isn't to say that he isn't curious, but I don't think the "why phase" is strongly related. When he's really interested in learning about something he wants to go interact with it. He also has other language abilities that he seems to use when what he wants really is information, like "I want to talk about it" and non-why-questions. Why questions seem to be just a button-mash for "make the adults talk to me".
My firm conclusion going into this is the why game is about getting the adult to interact.
But because I love layered explanations, I have been mentally preparing for this phase for a long time. My daughter turned one recently, which means I only have a short while longer to wait.
She has no grasp of the trap into which she will toddle!
Yup, similar with my child. Maybe the first time the question is motivated by actual curiosity, but the following 99 repetitions of the same question have to be motivated by something else.
Most questions I get are repetitions of something that was already asked and already answered, and the child actually remembers the answer.
Getting the impression that not even children know how to ask good questions. It's a crucial skill that I've never seen taught, and I know that I don't have it.
I'm in the same room as one of my heroes, I know they're full of important secrets, I know they're full of vital techniques, I could ask them anything, but nothing comes, I just smile, I say, "nice to meet you", I spend all of my energy trying to keep them from seeing my finitude. I come away no bigger than before. I never see them again.
I want to learn to be better than this.
I have 7 kids, so I feel qualified to make some observations on this topic.
Kid #1 asked "why" questions all the time when she was young. As a teenager, her questions have definitely decreased in frequency. This is primarily because all the questions she had as a young child actually got answered. There was a LOT of low-hanging fruit, and she picked it when she was young. She is still curious; her teachers enjoy her genuine interest in learning. It competes with her love of fan fiction, though.
Kid #4 also has some curiosity, and asks questions, though not as often as Kid#1 ever did. He, too, has fewer questions as he ages.
Kids #2, 3, and 5 never actually went through a "why" phase. They ask "Why can't I have that candy bar?" but they don't ask "Why is the sky blue?" They ask practical questions about what, when, where, and they may be quite interested if there's an interesting demonstration of something, but curiosity isn't a big part of their makeup. I have also noticed other people's kids who aren't that curious. People who say that all young kids are curious are basing that on observations of kids who are. Confirmation bias: they aren't looking for kids who aren't curious.
Kid #6 isn't very curious, but she is extremely social and wants to always hear the sound of her voice and mine, so she asks lots of questions and then doesn't listen to the content of the answers. Kid #7 's vocab consists mostly of a handful of food items and "shoes", so her curiosity can't be gauged yet.
So I'd say it's not the case that most young kids are curious and lose that as they grow older. Rather, most young kids are not that curious, and continue not to be curious as adults. The kids who are uber-curious grow up to be adults who are still curious, but whose questions are less incessant because they find answers as they go.
I know of no studies, nor even of good measures of "curiosity" to show whether this is a real effect or not. It could be that the kinds of questions that kids ask are actually low-value, and they (correctly) learn this after a few years. Some decades in, I retain a fair bit of curiosity, and much more ability to seek answers without pestering those who aren't likely to help.
Yeah, fair. Updated the title and OP to be a bit more agnostic about the phenomenon.
(I do think "asking why" isn't necessarily the active ingredient I'm interested in. I think it's quite plausible, as Alicorn notes elsethread, that the "why?" pattern is more like random verbal patter, or serving some other function, but that there's still some other facet of kids having a more direct, gears-y interaction with the world that’s more curious than most adults. This is still the sort of thing I might just be wrong about, but it feels like there's something there).
Where I live, adults traditionally worry their almost-grown children will be too curious if left unattended. It's not that people lose curiosity by when highschool ends (although they might), it's more like they have learned enough about the general structure of reality and choose what they want. I think.
A common story goes:
Young children love asking 'why', and they often have an earnest curiosity about it that is rare in adults. Something about the process of growing up seems to cause that childlike curiosity to stagnate.
There's a lot of compelling explanations about societal norms that actively stamp out that curiosity (i.e. school training kids to conform and regurgitate facts, parents subtly punishing kids for asking questions, etc). It seems likely to me that these are at least part of the story.
But it also wasn't obvious that they were the whole story. I could easily imagine it also just being the case that small children are optimized for learning and older humans are optimized for doing and the brain automatically shifts away from it. [edit: or that this whole thing is imagined]
Are there any cross-cultural studies that do anything to check how this phenomenon varies, depending on upbringing?