Investigating the effects of news sharing and political interest on social media network heterogeneity

•We investigated whether SNS use promotes the encounters with dissimilar ideas.•Frequent SNS use entails a greater chance of interacting with heterogeneous others.•News sharing activities mediate the link between SNS use and network heterogeneity.•Political interest moderates the link between news sharing and network heterogeneity. This research investigated whether the use of social networking services (SNSs) promotes or restricts the likelihood of citizens’ exposure to political disagreement by focusing on two different types of news sharing activities on SNSs – news externalizing and internalizing – and on individuals’ level of political interest. The results show that frequent SNS use may entail higher chances of interacting with heterogeneous others, but the influence is only indirectly exerted through its effects on two news sharing activities. Findings also indicate that political interest and news sharing activities interact with each other in predicting the degree of network heterogeneity. The study is conducted with a nationally representative survey.