I wouldn't say that. I think generally he's always open to learn new things and since he's a very intelligent person it's not hard for him to expand his horizons. I don't think it's necessarily because of Yennefer, although it is true he always tried to please her and that she prefers people of a certain intellectual level. She did indeed rub off some of her personality/quirks on him. For example she taught him to eat with a fork and knife and wouldn't let him do it any other way when they lived together.