I think it's interesting to note the lack of significant correlation between either IQ or calibration(as a proxy for rationality and/or sanity) and various beliefs such as many worlds. It's a common sentiment here that beliefs are a gauge of intelligence and rationality, but that doesn't seem to be true.

It would be interesting to include a small set of IQ test like questions, to confirm that there is a huge correlation between IQ and correct answers in general.