Bias accusations have eroded trust in journalism to impartially check facts. Traditionally journalists have avoided responding to such accusations, resulting in an imbalanced flow of arguments about the news media. This study tests what would happen if journalists spoke up more in defense of their profession, while simultaneously also testing effects of doing more fact checking. A five-day field experiment manipulated whether an online news portal included fact check stories and opinion pieces defending journalism. Fact checking was beneficial in terms of three democratically desirable outcomes–media trust, epistemic political efficacy, and future news use intent–only when defense of journalism stories were also present. No partisan differences were found in effects: Republicans, Democrats, and Independents were all affected alike. These results have important implications for journalistic practice as well as for theories and methods of news effects.

President Donald Trump faced substantial scandal coverage early in his presidency. Can these stories about presidential controversies change the opinions of Trump’s fellow Republicans, or are the efforts of the news media to inform partisans about prominent issues futile? Past research on partisan reactions to major political scandals were confounded by problems with self-reported media use and single-shot experimental treatments. We address these concerns using a unique, repeated-exposure experimental design that either randomly supplied participants with news about the Trump-Russia scandal, or removed most of those stories from view, over the course of one week in June 2017. This design mimics sustained media attention to a political scandal and disentangles the effects of media coverage from selection in the context of a high-choice media environment. We find that Republicans randomly assigned to see more Trump-Russia headlines reacted more negatively than Democrats or Independents, rating Trump’s performance lower and expressing more negative emotions about him. Republicans’ perceptions of media bias were not affected by Trump-Russia stories, and effects were not contingent upon clicking the articles. Intense media focus on a story can alter partisans’ evaluations of politicians by shifting the balance of headlines.

Previous study demonstrates that partisans perceive in-party news outlets as fair, and out-party news outlets as unfair. However, much of this study relies on one-shot designs. We create an ecologically valid design that randomly assigns participants to news feeds within a week-long online news portal where the balance of in-party and out-party news outlets has been manipulated. We find that sustained exposure to a feed that features out-party news media attenuates Democrats' beliefs that Fox News is unfair, but the same is not true for Republican's perceptions of MSNBC's fairness. Unexpectedly, repeated exposure to in-party news did increase Republicans' beliefs that Fox News is unfair. This study updates our understanding of partisan news effects in a fragmented online news environment.

What happens when news aggregators tailor their newsfeeds to include partisan news aimed at users with a known party preference? Relying on a custom-made news portal featuring real, timely articles, this study examines the influence of partisan news sources on participant headline exposure, clicks on news stories to read, and perceptions about the portal’s ability to reliably and comprehensively provide the most important news of the day. Over a period of 12 days, participants preferring either the Republican or Democratic party were randomly assigned to newsfeeds containing increased dosages of real news articles from sources supportive of the participant’s preferred party. Results demonstrate that partisan personalization can benefit a news aggregator by increasing usage and perceptions of its quality, while potentially harming society by decreasing attention to high-quality mainstream sources.

Publics hold chief executives uniquely responsible for national well-being, and they learn about national conditions through news. But when news disproportionately covers problems, what happens to democratic accountability? Here, we experimentally test how leader approval changes when crime loses prominence in news for a sustained period. We create an online news environment coding real news in real time, then experimentally filter news for nationally diverse U.S. panelists over 1 week. We find causal evidence that reducing crime news raises presidential approval and depresses problem importance evaluations for crime. No other leaders are credited, and reducing all problems produces no further gains. These effects persist well after exposure but dissipate within a week. We conclude with broad implications for journalism and democratic judgment.