I'd take a different approach than Tim here. I think you look at different things moreso than looking at the same things which have changed. For instance, an immature male, when looking at a woman, will evaluate various body parts between her neck and her knees. As that boy becomes older and (hopefully) more mature, he changes his way of looking at things, and instead of evaluating women on those features, he'll metaphorically look at her personality, sense of humor, intelligence, beliefs, et cetera, or, if you want something more physical, will look at her eyes, her smile, and the like. He's changed the way he looks at women, and looks at entirely different things. So you have a science-y answer from Tim, and a more philosophical (not the word I want, but it will suffice) one from me.