Social influence on social media. How majority and in-/outgroup opinions on personal newsfeeds impact opinion formation on new issues

Social media platforms play a central role in shaping public opinion on political and societal issues. Users are constantly exposed to a mix of algorithmically and socially filtered content, which can influence how they perceive new topics and form attitudes. Drawing on theories of heuristic information processing, social impact, and social identity, an experimental study explored the impact of opinions in a social media newsfeed on users’ selective attention, evaluation, and opinion formation. A 2x2 design with N = 197 participants, integrating forced and selective exposure elements, confronted subjects with a novel (fictitious) issue and a feed of six related opinion posts. Two factors were analyzed: (1) whether posts – in favor or against the issue – came from voices that participants identified as ingroup versus outgroup, and (2) whether the pro or con posts were in the majority versus minority. Results show that posts from ingroup voices do not receive more attention than outgroup posts but are perceived as more credible in general and are more persuasive under certain conditions: When ingroup posts are in the majority and when users are low-involved. The persuasive effect also occurs when the ingroup is hardly related to the issue under discussion. This underscores that no impermeable filter bubbles are needed to influence user opinions on social media. According to the results, persuasion takes place on social media when individuals are predominantly confronted with the opinions of people with whom they feel close and connected–regardless of whether this connection is topic-specific or not.