(a) He’s so obsessed with himself. He keeps looking at himself in the mirror.
(b) He’s so obsessed with himself. He keeps watching himself on the mirror.
As a native speaker of English, I know that sentence a is correct, and that sentence b feels wrong. Why? Well, that’s an important question that I need to figure out the answer to. Oxford Learner's Dictionary gives:
Look at (phrasal verb)
- To examine something closely.
- To think about, consider or study something.
- To view or consider something in a particular way.
- To look at somebody/something for a time, paying attention to what happens.
- To take care of somebody/something for a short time.
- To be careful about something.
- To pay attention to a situation so that you notice any changes.
- To observe somebody’s activities without their knowledge, especially over a period of time.
What the above definitions tell me is that while it makes sense to “look at yourself in the mirror,” it does not make sense to “watch yourself on the mirror.” Why? I think it is because nothing happens when you look at yourself in the mirror. If you substitute mirror for TV, it would be fine, because you be watching footage of yourself doing something.
I would appreciate any answers that I can get on this.