Illusory Truth and Partisan Motivated Reasoning

• In Event: The Online and Offline Effect of Misinformation

Abstract

The proliferation of “fake news" has been a growing concern, particularly with technological advancements and the widespread use of social media platforms. A long-standing question in this literature has been the psychological drivers behind beliefs in misinformation. While motivated reasoning is often explored by political scientists as a primary driver shaping belief in misinformation, cognitive psychologists have advanced an alternative mechanism through which social media makes misinformation more believable by simply facilitating users' exposure to false rumors online.

Extensive research in cognitive science demonstrates that prior and repeated exposure to a statement increases the likelihood that participants will judge it as accurate, particularly outside of politics ​​(see Fazio et al. 2015). More recently, Pennycook et al. (2018) tested these theories in the context of highly partisan online misinformation, assessing the possibility that motivated reasoning imposes certain scope conditions on ‘illusory truth effects’. The authors find that even a single exposure to false headlines increases subsequent perceptions of accuracy, both within the same survey and in a subsequent survey after a week.

Our study builds on this literature to assess if prior exposure to online misinformation affects accuracy judgments and the extent to which partisan-motivated reasoning moderates these results. Our survey experiment builds on existing designs in the field (Pennycook et al., 2018; Lyons, 2023). We measure the effects of familiarizing participants with false and true headlines in the first stage of the survey, and measuring the effects of this prior exposure on accuracy statements at the end of the same survey and a second wave taken one day later.

Our design modifies previous experiments in three main directions. First, we focus on between and within-subject treatment effects by preserving a pure control group that gets familiarized with false statements that do not appear in the accuracy judgments later. Second, to measure the role of motivated reasoning, we add source cues from well-known liberal and conservative media outlets on the headlines used during the experiment. Third, our designs used a high-quality online sample with quotas to match the demographics of the United States adult population.

By experimentally manipulating both the prior exposure to a headline, as well as the partisan congruence of the headline’s source and content, we subject two dominant perspectives on belief in misinformation to a test. Does the illusory truth effect dominate belief in fake news, as concluded by the psychology literature? Or is partisan motivated reasoning paramount, as suggested by the political science literature? Furthermore, how do these two frameworks interact?

We have pre-registered our hypotheses, experimental design, and empirical specifications at OSF, and have begun collecting data in partnership with Qualtrics, using a nationally representative sample of Americans along the dimensions of age, gender, race, partisanship, and region. Our experiment is in the field from January 16th through January 24th, 2024. We look forward to analyzing the data in the spring, addressing an important gap in the social scientist’s consensus on the drivers of belief in fake news.

Authors

• Tiago Augusto da Silva Ventura, Georgetown University

• James Hodgdon Bisbee, Vanderbilt University

• Sarah Graham