[new2628]

That's an interesting response, thanks! I think where I disagree is that I think people are pretty smart, at least in one thing, which is survival -- the proof of that is that those who were not, quickly exited the gene pool. That is a powerful filtering that tunes our estimators.

I agree with your last paragraph, but I think it supports my point. I wear a mask because it has zero cost, and it may save my life. When I took this decision, I didn't estimate any probabilities and I haven't used Bayes theorem. Understanding what a mask does exactly and how aerosol transmission of viruses work precisely is almost irrelevant to my decision -- I could be improving my knowledge ("my priors") by studying virology, but there would still be so many uncertainties, that it would hardly influence my decision.