Proximate or Primary Source? How Multiple Layers of News Sources on Social Media Predict News Influence

News shared on social media presents multiple layers of sources, from reputable news organizations to individual users who share news on social media. A web-based experiment investigated (a) whether the influence of a primary news source (news organization) on viewers decreases as it becomes less proximate with the presence of a more immediate source (individual user who shared news), and (b) if so, how the evaluations of both sources, along with a varying degree of issue relevance, affect viewers' agreement with news position. Participants read one news article either shared on Facebook by a well-known celebrity or directly posted onto a news website. The perceived credibility of news organizations predicted viewers' agreement with the news position, but only when the news was presented on a news web page so that the news organization was shown as the proximate source. When multiple sources were displayed, the influence of news organization credibility disappeared when the given news lacked personal relevance.