Psychological interventions against misinformation and ideological bias

As the world faces crises such as the Russian war against Ukraine, climate change, and COVID-19, evidence-based responses are crucial. Yet, the widespread dissemination of false, biased, and manipulative information threatens informed decision-making. This dissertation explores how psychological interventions can counter misinformation and ideological bias. It aims to (1) systematically review existing interventions, (2) highlight the roles of social identity and ideology in motivated reasoning, and (3) test selected interventions in real-world contexts. Study 1 presents a systematic review of 176 research articles on psychological interventions against misinformation. Most studies focused on fact-checking, lacked theoretical integration, and rarely addressed motivated reasoning. Study 2 tested a strategic, text-based inoculation against Russian disinformation. Social identity emerged as a key susceptibility factor in motivated reasoning. The inoculation reduced the perceived credibility of Russian disinformation and even shifted attitudes on the Russian war against Ukraine—regardless of identification strength. Study 3 examined a feedback intervention to reduce ideological bias in interpreting scientific evidence. Feedback significantly reduced ideological bias among both liberals and conservatives. However, adding a social norm nudge had no additional benefit. This dissertation deepens the understanding of the emerging, interdisciplinary research field of interventions against misinformation and ideological bias. It theoretically advances the field by introducing novel concepts and illuminating the roles of social identity and ideology in information processing. Moreover, it emphasizes the need for scalable solutions to strengthen resilience against misinformation and ideological bias at both individual and societal levels.