I think I'm a slow thinker. And that's because I have ADHD and a number of learning disabilities including dyslexia and dyscalculia, and also short term memory problems. It takes me twice as long to do things as normal people. I'm smart, but if the game is "do this thing quickly and accurately" then my results will make me seem very dumb. I did manage to get a Ph.D. but only because it's the kind of thing that doesn't require you to be fast and accurate, but slow and deliberate. I can do that very well. But then people see the Ph.D. and think that means I'm a fast thinker, and they are often very disappointed I am not.

So you're right, I do self limit by labeling myself as a slow thinker, but I think it's for the best because otherwise people overestimate me and end up disappointed.

Yeah, it sounds like this label might fit on you, but I'd still be interested in seeing any studies about it.

I do feel that most people who label themselves as "slow thinker" aren't actually having the kind of issues you describe though, similarly how most people say they have "bad memory" even though most people have typical memory.