I remember seeing some kind of a study, or maybe it was actually a social experiment, that tested people's opinions on different versions of a proposed policy change affecting different income brackets in different ways. And it showed that almost everyone's opinion changes depending specifically on when it affected *their own* income bracket in particular: in other words, it showed that most people vote out of self-interest above any other ideal about "what's good for society" or whatever.

But I've been looking for it and I can't find it. Does anyone know what study I'm talking about? If not, I'd like to see any studies or social experiments in the same vein.