Say It Ain't So.
Manuel Castells bored me rigid tonight while discussing his new book about power relations and networked societies, but he did suggest that a nugget of information is five times more likely to register in one's brain if it conforms to one's existing beliefs.
He suggested that this was why liberals listened to NPR and Republicans watched Fox News and that the media didn't actually lead opinions. I saw it as powerful confirmation of the idea that communications can only bolster what people already believe about specific products and services. If your product/service isn't credible, you can't convince people otherwise.