[nomel]

I don't think it has anything to do with brain development. I think it's entirely related to the development of an individual concept, whenever the structure of ideas that make the concept is too simple.

I would claim that most people use intuition/assumptions rather than internal chain-of-thought, when communicating, meaning they will present that simplified concept without second thought, leading to the same behavior as the toddler. It's actually trivial to find someone that doesn't use assumptions, because they take a moment to respond, using an internal chain-of-thought type consideration to give a careful answer. I would even claim that a fast response is seen as more valuable than a slow one, with a moment of silence for a response being an indication of incompetence. I know I've seen it, where some expert takes a moment to consider/compress, and people get frustrated/second guess them.