Suzanne Hidi:  Curiosity has been often referred to as closing a knowledge gap. And this goes back to Burlein's work, goes back to a lot of work being done by Litmen and his colleagues presently would distinguish between two forms of curiosity, interest, epistemic curiosity and knowledge gap curiosity, deprivation they call it. The reason why they call it deprivation is because there has been an argument that if you are curious there is a certain kind of negative feeling that you experience before your curiosity is satisfied. And once you have this answer you feel a relief and a positive feeling comes over you. We argue that if you are interested and you are searching for more information that is a rewarding experience and you do not necessarily or you are unlikely to have any aversive feeling, except you can have negative feelings develop because you have a problem in your search. But that's different than trying to close a knowledge gap. The way that I can best demonstrate you how we consider curiosity and interest to be different is by telling you to think about when you read a detective story. When you read a detective story the minute you find out who actually is the murder you might not even want to finish your book. And compare that to reading let's say Harry Potter or some really well constructed book that you're not simply trying to find out a knowledge gap, you are interested in many of the characters, you are interested in the ideas, you are interested in the relationships and you will keep on reading that book. Not only is the length of time different and the aversion different but also the purpose is different. Like when you are interested you are searching for a lot of information, not just a specific information to close the knowledge gap. Now, there are some unanswered issues about this. For example, what happens if you have interest in a content but there is a knowledge gap that you're closing, is that now different from just being curious? And we argue that it is. Because, for example, take a bridge expert who loves playing bridge, he is reading a book with many, many puzzles solving bridge hands. He goes and solves a knowledge gap and then continues going on to other questions, other puzzles because he has that individual interest in the content that propels him to go on for further activity.