Conservatives and Humor

Via HuffPo, it seems that conservatives have difficulty detecting satire.

This study investigated biased message processing of political satire in The Colbert Report and the influence of political ideology on perceptions of Stephen Colbert. Results indicate that political ideology influences biased processing of ambiguous political messages and source in late-night comedy. Using data from an experiment (N = 332), we found that individual-level political ideology significantly predicted perceptions of Colbert's political ideology. Additionally, there was no significant difference between the groups in thinking Colbert was funny, but conservatives were more likely to report that Colbert only pretends to be joking and genuinely meant what he said while liberals were more likely to report that Colbert used satire and was not serious when offering political statements. Conservatism also significantly predicted perceptions that Colbert disliked liberalism. Finally, a post hoc analysis revealed that perceptions of Colbert's political opinions fully mediated the relationship between political ideology and individual-level opinion.

It would be easy to just laugh at those dumb conservatives, but I'm genuinely curious as to why this is so. Why do conservatives have a harder time realizing that Colbert is a parody? By the same token, if there was a similar show with a conservative ideological bent, would liberals be able to identify it as satire?