This one is a weird situation that came to a head yesterday but, now that I look back on it, the behaviour has been there for months.
My seven year old has indoor and outdoor shoes at school. The indoor shoes are labeled with his name, written in my wife's handwriting on very specific labels. Yesterday, he got confused because he thought that the shoes had a pure white "S" on them when in fact the "S" is black. He convinced himself that these were not his shoes.
Usually, I'd expect this to clear itself up quickly - a talk about how maybe he forgot exactly what color the S was supposed to be, showing him the labels on his other things and how they are the same label with the same writing, that sort of thing. But he just won't accept that. He is referring to them as "the shoes you are forcing me to wear" and adamantly refuses to believe that they are actually his shoes. He is coming up with more and more elaborate reasons why they aren't his shoes (perhaps another kid swapped out their shoes and moved the label, perhaps we are lying to him and swapped them ourselves etc).
Now, I know my son and I know that he's not just saying these things to avoid having to admit he was wrong. He actually believes that these are not his shoes, and as such I'm a bit concerned. When I look back I can see that he has done similar things in the past, but up until now I just assumed he was trying to cover up his embarrassment about being wrong. As an example here, he made a mess with water in the bathroom but told us that it must have just been the "steam" coming off of the sink, and he similarly talks about that incident as "the steam on the floor" rather than splashing water. There are lots of other incidents of this happening.
So...has anyone seen this before? What might be the cause of it? Is it something to be concerned about? I tagged the question as "discipline" but that's probably not right, I just couldn't think of a tag that even begins to describe this.