Karen M. Douglas

Four pre-registered studies examined the semantic and causal relation between conspiracy mentality and belief in conspiracy theories. Study 1 ( N = 251) confirmed important differences between these two constructs. Participants perceived conspiracy mentality propositions as general rules and conspiracy theories as specific examples. This perception that conspiracy mentality statements are more general was associated with the perception that they are more plausible and, if shared, less likely to cause dispute and to stigmatize the communicator. Conceptualizing them as different constructs, Studies 2–4 together indicate that they might have a bidirectional causal relationship with each other. Affirming conspiracy theories set in real-world and fictional societies increased participants’ conspiracy mentality scores, relative to negations of conspiracy theories (Studies 2, 3) and a baseline condition (Study 4). Conversely, affirming conspiracy mentality statements increased participants’ endorsement of conspiracy theories (Study 4). The semantic relation between the two constructs means each may reinforce the other through inductive and deductive reasoning. Nonetheless, important social-psychological differences may emerge between them due to the greater specificity and epistemic riskiness of conspiracy theories compared to the conspiracy mentality.