2008 would have been the yr for the Bradley effect. It didn't happen then so why now? Most voters already voted for him 2008 and know him. I'm sure a small percentage exist but not much. Same for the Mormon effect. I personally know people that won't vote for Romney because he's Mormon.
Yeah, if the bradley effect is even real to begin with, we would have seen it in 2008. Now people can genuinely say that they don't approve of his job approval and thus vote against him. There was no bradley effect in 2008 and there won't be one in 2012.