False consensus in the echo chamber: Exposure to favorably biased social media news feeds leads to increased perception of public support for own opinions

Studies suggest that users of online social networking sites can tend to preferably connect with like-minded others, leading to “Echo Chambers” in which attitudinally congruent information circulates. However, little is known about how exposure to artifacts of Echo Chambers, such as biased attitudinally congruent online news feeds, affects individuals’ perceptions and behavior. This study experimentally tested if exposure to attitudinally congruent online news feeds affects individuals' False Consensus Effect, that is, how strongly individuals perceive public opinions as favorably biased and in support of their own opinions. It was predicted that the extent of the False Consensus Effect is influenced by the level of agreement individuals encounter in online news feeds, with high agreement leading to a higher estimate of public support for their own opinions than low agreement. Two online experiments (n1 = 331 and n2 = 207) exposed participants to nine news feeds, each containing four messages. Two factors were manipulated: Agreement expressed in message texts (all but one [Exp.1] / all [Exp.2] messages were congruent or incongruent to participants' attitudes) and endorsement of congruent messages by other users (congruent messages displayed higher or lower numbers of “likes” than incongruent messages). Additionally, based on Elaboration Likelihood Theory, interest in a topic was considered as a moderating variable. Both studies confirmed that participants infer public support for their own attitudes from the degree of agreement they encounter in online messages, yet are skeptical of the validity of “likes”, especially if their interest in a topic is high.