It's about recognizing differences in appearance based on association with others of the same species. If I've never looked in a mirror but I know what my mothe

It's about recognizing differences in appearance based on association with others of the same species. If I've never looked in a mirror but I know what my mothers face looks like, I don't need to have ever seen my own face to know that I probably have two eyes, a nose, and a mouth. They do this experiment with human babies: At a certain stage, if you put something on their head they will recognize that it doesn't belong there, because they recognize that something is "different" about the human appearance in the mirror.