Jessica Winter has a great list on Slate of breakthrough performances with an unusual focus. I always love the thrill of discovering a new talent; it is one of the greatest pleasures the movies bring us. But Ms. Winter makes the point that these mesmerizing newcomers can do something a star cannot. We are happy to buy tickets to see our established favorites like Will Smith, Tom Hanks, and Julia Roberts. But the very thing we love about them — our knowledge of them, even our sense of a fan relationship with them — makes it impossible for them to disappear into a role the way a newcomer does. Every time we see an actor we learn a little more about the individual as we observe the performance. There are gestures and expressions that stay the same from role to role. But a first performance can transfix us into dissolving the line between actor and character. Winter’s examples all come with very telling clips illustrating her point.