It is difficult for people to be persuaded by competing media accounts during a contentious election campaign; the real consequence of online partisan media may be an erosion of trust in mainstream news

The consequences of online partisan media. Andrew M. Guess et al. Proceedings of the National Academy of Sciences, April 6, 2021 118 (14) e2013464118; https://doi.org/10.1073/pnas.2013464118

Significance: Popular wisdom suggests that the internet plays a major role in influencing people’s attitudes and behaviors related to politics, such as by providing slanted sources of information. Yet evidence for this proposition is elusive due to methodological difficulties and the multifaceted nature of online media effects. This study breaks ground by demonstrating a nudge-like approach for exploring these effects through a combination of real-world experimentation and computational social science techniques. The results confirm that it is difficult for people to be persuaded by competing media accounts during a contentious election campaign. At the same time, data from a longer time span suggest that the real consequence of online partisan media may be an erosion of trust in mainstream news.

Abstract: What role do ideologically extreme media play in the polarization of society? Here we report results from a randomized longitudinal field experiment embedded in a nationally representative online panel survey (N = 1,037) in which participants were incentivized to change their browser default settings and social media following patterns, boosting the likelihood of encountering news with either a left-leaning (HuffPost) or right-leaning (Fox News) slant during the 2018 US midterm election campaign. Data on ≈ 19 million web visits by respondents indicate that resulting changes in news consumption persisted for at least 8 wk. Greater exposure to partisan news can cause immediate but short-lived increases in website visits and knowledge of recent events. After adjusting for multiple comparisons, however, we find little evidence of a direct impact on opinions or affect. Still, results from later survey waves suggest that both treatments produce a lasting and meaningful decrease in trust in the mainstream media up to 1 y later. Consistent with the minimal-effects tradition, direct consequences of online partisan media are limited, although our findings raise questions about the possibility of subtle, cumulative dynamics. The combination of experimentation and computational social science techniques illustrates a powerful approach for studying the long-term consequences of exposure to partisan news.

Keywords: mediapoliticspolarizationcomputational social science