I would have a bit of a hard time to recommend some citations without narrowing the interest a bit. There are quite a lot of great papers. Kind of the granddaddy of modern curiosity research is:
I am really sorry. I do not know if there is an open access version of this paper.
If you start from there and then find work that cites that, you will be able to find most modern curiosity research, I would wager. Not everyone agrees with what followed from this, but pretty much everyone has to contend with it in one way or another. I would claim that there is not really a consensus, but "knowledge gap" (or "information gap") and "uncertainty" are probably the most prominent and influential keywords.
***
Okay, I did a bit more digging in my file system and found a reasonably recent overview by two fairly prominent researchers that might serve as a decent starting point. While I don't agree with everything here, that hardly matters of course. It's a place to start.
I think it is open access. It is for me in firefox with no javascript enabled, anyway.
