What does it take to sustain the illusion: addendum

I forgot about social pressure!

That is, how many people claim that they still believe something either because it’s embarrassing to admit they were wrong, or because doing so means weakening their ties to the social networks that nurtured and sustained their beliefs in the first place–and losing a lot of friends in the process?

Put another way, for any given difficult-to-sustain belief, how many apparent believers are merely pretending?