I'm always on the lookout for further evidence that preconceptions shape our perception of reality. Princeton professor and political scientist Larry Bartels showed how political beliefs shape our perception of objective economic facts. His abstract reads:
In contrast to the notion of partisanship as a simple 'running tally' of poltical assessments, I show that party identification is a pervasive dynamic force shaping citizens' perceptions of, and reactions to, the political world...I conclude that partisan bias in political perceptions plays a crucial role in perpetuating and reinforcing sharp differences in opinion between Democrats and Republicans. This conclusion handsomely validates the emphasis placed by the authors of The American Voter on 'the role of enduring partisan cimmitments in shaping attitudes toward political objects.'
He goes on to show how self-identification as a Democrat or Republican influences how a person perceives objective economic facts, such as unemployment or inflation.