The biggest reason, they found, was that our perceptions have little to do with politics or passions, but more to do with our understanding of the world and our place in it. If we don't feel a threat to our immediate world, we will change our beliefs; say, a friend corrects you about how a vacuum works. But when the information changes something we've long held on to as truth, sparks fly. This is because we internalize information that affects our world--being a good mom means watching out for my child's wellbeing, for example. If being told that vaccinating my child will harm my child, I may change my belief's on vaccines to keep that identity I've created of what makes a good mom. When we feel like our sense of self is threatened, we rally even stronger around these misconceptions.
Similarly, in the book Age of Propaganda by Pratkanis and Aronson, the authors note that our desire to be consistent in our beliefs and actions can lead us to do sometimes illogical things to defend our image. If we feel our sense of self threatened, we either change our attitude about the subject, or we change our behavior (suddenly becoming and ardent proponent or blind follower, for example). This can mean rationalizing a misconception and refusing to "hear" the facts, all in the same of self preservation.
The New Yorker, May 2014
