The Devil is in the Detail: An Investigation into Belief in Conspiracy Theories

Researchers disagree on how to capture people's tendency to believe in conspiracy theories. Some researchers argue the conspiracy mentality is this general tendency (Imhoff et al., 2022a) and the predisposition to it (Imhoff & Bruder, 2014), while others argue that this tendency is found in the aggregate beliefs of conspiracy theories (Sutton & Douglas, 2020). This debate notwithstanding, researchers tend to treat beliefs in conspiracy theories and the conspiracy mentality as the same construct, often using measures interchangeably (Imhoff et al., 2022a). This thesis presents a sustained investigation of differences between these measures and the constructs with which they are associated: namely, the conspiracy mentality (scales comprising abstract items about elites deceiving and controlling the public) and belief in conspiracy theories (scales comprising disparate, specific conspiracy theories, e.g., about JFK and AIDS). It provides the first empirical evidence for their psychometric and functional differences as well as their causal relationship. In Chapter 2, factor analyses of seven self-report surveys (n = 2719) showed scales of conspiracy mentality and of belief in conspiracy theories to be distinct constructs. In regression models, these studies further showed that belief in conspiracy theories uniquely predicts climate change denial and other anti- science attitudes. In Chapter 3, an additional study showed that this might be because conspiracy mentality statements are considered as general rules, and as such more plausible, less likely to cause dispute and to stigmatize the communicator, than belief in conspiracy theory statements. Four experiments then showed that these two constructs might have a bidirectional causal relationship. I conclude that conspiracism has two distinct aspects: the general sentiment behind conspiracy theories (captured with the conspiracy mentality), and the specific narrative of conspiracy theories (captured through belief in conspiracy theories). This conclusion paves the way to a new research agenda in which the conspiracy mentality and belief in conspiracy theories are studied independently, and, mindful of their conceptual differences, adopted to investigate the unique contribution of each to the social consequences of conspiracism.