Jane, at first, perked up and her smile grew when she realized that this was Thor's brother. That merged into confusion with his last statement. She was trying to remember meeting someone that looked like him but was smaller, like Scanlan.

"Oh you're Thor's brother, he's mentioned you a lot, but you were smaller before?" As soon as the words were out she thought back through what Thor had said about him. Before Loki could comment she said, "wait, Thor said something about practical jokes that you always played on him. Was that part of the smaller?"