I have a piece up for The Guardian’s new Comment is Free Belief site, The use and abuse of statistics – Prophecies of the extinction of religion, or its triumph, fall prey to the weaknesses of linear prediction. Implicit in my argument are these sorts of dynamics:
Bearman and Brückner have also identified a peculiar dilemma: in some schools, if too many teens pledge, the effort basically collapses. Pledgers apparently gather strength from the sense that they are an embattled minority; once their numbers exceed thirty per cent, and proclaimed chastity becomes the norm, that special identity is lost….
This is in regards to virginity, but the insight is generalizable. You don’t have to know anything about dynamics though, just read a cultural history of France since the Revolution and you’ll see what I mean.