Hi — officially designated paranoid schizophrenic checking in!
Interesting theory. I like your general ‘NP’ theory better than your conjecture about how and why it goes haywire, though.
I’m more inclined to stress context. If I plucked the average person up from their locale and plunked them down in an imaginary world where people’s behavior made no sense when one made the default assumption that they were all just ordinary people making reasonable assessments of things around them, that average person would most likely start wondering “what the fuck is up with these people?”, and, furthermore, because these people’s behavior isn’t following normal expected trajectories, that average person would feel a bit scared of them, right? If you can’t predict the behavior of people around you (in the general everyday “ordinary people do normal things” kind of way), you don’t know what they’re going to do next, right?
Well, people obtain their sense of logical “normal” behavior on the part of other people the same way they reality-check their own perceptions —we project what we think, feel, perceive, or think that we would think, feel, or perceive if we were in the other person’s situation as we comprehend it, and then we compare notes with other people to see if we’re all sort of seeing things the same way, give or take a small margin of variation.
When your estimation of how other people would logically behave totally tanks in the face of very different behavior, you could conclude “Aha, my brain is messed up, that’s why I’m not behaving just like these other jerks”, but it’s far more likely that you’re going to think there’s an in-joke that you’re just not in on (“All right, I give up, why is everyone hiding under their desks when the receptionist walks in instead of saying ‘Hi Judy did you have a nice vacation in Haiti’? What did I miss out on?”) — right? Then, if some initial probing seems to eliminate that possibility (your coworkers insist with seriousness and anger that hiding under the desks is the only rational behavior and they’re irritated that you’d question it or think something ‘funny’ is going on), it’s liable to make you angry, feel a bit threatened, and you start thinking they’re clued into something that you’re left out of but in a darker way. (“Oh shit, my whole office must be composed of folks who seriously believe that Judy’s voodoo jokes last week were for real…either I’m working with religious fundamentalist fruit-bats and never knew it or I’m the oblivious innocent about to be hexed by an evil bruja, either way get me out of here…”).
In other words, it’s mainly a normative emotional-perception reaction to not being on the same wavelength as the people around you to the point that you don’t feel safe around them. What compounds it is that when this is happening you don’t have anyone to compare notes with to whom the world makes the same kinds of sense as it does to you. (“Hey Rob, what’s your take on this? The way everyone in the office is so weirdly avoiding Judy? I asked Pete and Joanne and they got all bristly…”) So whatever notion you entertain as a possible explanation is one that you’ve got to embrace or discard on your own, you don’t get to do the reality-checking thing 'cuz there’s no one to do that with, you’re on your own. Which adds to your fear.