Baby Vanity

Rolli has been obsessed with looking at himself in the mirror. Anytime we walk in the bathroom he gets this huge cheese smile on his face. I, of course, encourage this vanity by telling him how cute he is. I only slightly worry that this will become true vanity one day and not the self-confidence I hope to build with him.
I wonder at what point they truly recognize it as being themselves in the mirror. There is a theory that babies think that it is another baby looking back at them. I should get out my text books to find the proper reference. I tell him that that cute baby in the mirror is him, but I do wonder what he knows and thinks of this. Part of me wonders if they know it is themselves just because of their egocentrism. Everything revolves around them and there is not yet perspective taking, so why would it be a different baby in the mirror? If you know me, you know baby's brains fascinate me. I may someday get that phd in behavioral neuroscience so that I can do my own studies, but for now I just continue to wonder what they are thinking and what they know.
We have done lots of exploration with mirrors. Being a Mary Kay consultant, I happen to have lots of personal size mirrors. Different angles, under water, grouped together, separated, etc. he has spent the majority of several days looking in the mirror. Lol- can you blame him?