Knowledge Versus Beliefs: How Knowledge and Beliefs Mediate The Influence of Likeminded Media use on Political Polarization and Participation

Using cross-sectional data from the 2008 National Annenberg Election Survey, this study tests 2 models that explicate the relationship between politically likeminded media use and political polarization and participation. The knowledge model suggests that the effects of exposure to likeminded media on individuals’ attitudinal polarization and political participation are mediated by knowledge of candidate issue stances. The belief model proposes that likeminded media use indirectly influences political polarization and participation via political beliefs. The results provide evidence that individuals’ beliefs mediate the influence of likeminded media consumption on attitudinal polarization and participation, but there was no support for the knowledge model. These findings indicate that individuals who consume politically likeminded news tend to develop polarized attitudes and are motivated to participate in political activities by forming biased beliefs associated with candidates rather than by gaining factual issue knowledge.