Why partisans see mass media as biased

Partisan groups, highly important actors in public discourse and the democratic process, appear to see mass media content as biased against their own point of view. Although this hostile media effect has been well documented in recent research, little is understood about the mechanisms that might explain it. Three processes have been proposed: (a) selective recall, in which partisans preferentially remember aspects of content hostile to their own side; (b) selective categorization, in which opposing partisans assign different valences to the same content, and (c) different standards, in which opposing partisans agree on content but see information favoring the other side as invalid or irrelevant. Using new field-experiment tests with groups of partisans who either supported (n = 87) or opposed (n = 63) the use of genetically modified/foods, we found evidence of selective categorization and different standards generally. However, only selective categorization appeared to explain the hostile media effect.