Magic Mirror

Wondering something:

All three of our girls have the habit of talking into mirrors. I don't mean they go off by themselves and do goofy stuff in front of the mirror - everybody does that.

I mean, you're having a conversation with one of them, and instead of looking at you when she's talking, she's looking at herself in a mirror (e.g., a dresser mirror in the bedroom or the door mirror in the bathroom).

I can't count how many times I've said to them, "Talk to me, not the mirror." India seems to be growing out of it, but Anya and Quinn do it all the time.

What I'm wondering is, is this normal? Do other kids do this, or is this just another data point for the weirdness of our family?