Those examples are ones that can happen without knowing where you are, or who exactly you are currently talking to. Dementia can take that away, as well; but often people notice people with dementia not engaging directly and specifically with them in the now.

As an example, my grandparents would often think I was my father when I would visit them. If I tried to get them to talk to me, as me, expect confusion and nothing to make sense. Let them just talk, though, and what they were saying would make sense. Especially once I realized they were largely taking up a context I just wasn't in.