Claude Fischer writes:
"a pair of studies in the Quarterly Journal of Political Science (here and here) make the case that seeming conflicts between Democratic and Republican survey respondents on facts–say, on the unemployment rate, or on crime trends–are best understood not as expressions of different realities, but rather as expressions of identities. Many partisans take factual questions posed by pollsters as opportunities to declare who they are and whose side they are on. For instance, partisan respondents describe the economy as booming when their party holds the White House and as miserable when their party doesn’t. However, if pollsters offer respondents money for a correct answer (or to admit that they do not know the answer), the big gaps between Democrats’ and Republicans’ replies narrow greatly. Identity and emotion lie behind the answers at least as much as understandings of the facts."