After reading this one, I've really noticed that I at least behave just like that. My brains tends to guess what people are talking about, when I hear someone talking to the phone. That's just funny. If you pay attention to this, you probably notice the same.
I think this gives us right to overhear phone conversations.
I just hope I would have taken note which study it was and where it has been made. It would be nice to dig bit more on it.