The life cycle of conspiracy theories: evidence from a long-term panel survey on conspiracy beliefs in Italy

Abstract Conspiracy theories are gaining increasing interest in academic and public debate. A broad research agenda focused on the socio-political and psychological determinants of conspiracy theory beliefs, on the effect of social media as a new channel of dissemination, on the role played by populist leaders in explaining those theories, and on the impact on social and political outputs. This introduction to the special issue proposes a summary of this growing literature and addresses an aspect that is still under-investigated: the life cycle of conspiracy theories. Previous empirical studies investigated the topic either in a cross-sectional fashion or by employing short-term panels – focusing on how conspiracy theories change over a small period (e.g., before and after an election). Using panel survey data, we take a medium-term approach. We base our investigation on a longitudinal study composed of two survey waves, administered in 2016 and late 2020. Respondents were asked to rate the plausibility of different ‘classic’ conspiracy theories. This allows comparing changes in beliefs in those conspiracy theories over this 4-year time frame. Results show that believes in these theories decrease over time. Furthermore, this decline can only be marginally explained by individual socio-demographic characteristics or political orientations. After thoroughly describing these differences over time, we speculate on why this decline occurs, mainly basing our argument on the role of the media landscape in shaping public opinion.