Interest (emotion)

Interest is a feeling or emotion that causes attention to focus on an object, event, or process. In contemporary psychology of interest, the term is used as a general concept that may encompass other more specific psychological terms, such as curiosity and to a much lesser degree surprise.

The emotion of interest does have its own facial expression, of which the most prominent component is having dilated pupils.

https://en.wikipedia.org/wiki/Interest_(emotion)