Résumé

What are the underlying cognitive mechanisms that support belief in conspiracies? Common dual-process perspectives suggest that deliberation helps people make more accurate decisions and decreases belief in conspiracy theories that have been proven wrong (therefore, bringing people closer to objective accuracy). However, evidence for this stance is i) mostly correlational and ii) existing causal evidence might be influenced by experimental demand effects and/or a lack of suitable control conditions. Furthermore, recent work has found that analytic thinking tends to increase the coherence between prior beliefs and new information, which may not always lead to accurate conclusions. In two studies, participants were asked to evaluate the strength of conspiratorial (or non-conspiratorial) explanations of events. In the first study, which used well-known conspiracy theories, deliberation had no effect. In the second study, which used relatively unknown conspiracy theories, we found that experimentally manipulating deliberation did increase belief accuracy - but only among people with a strong ‘anti-conspiracy’ or strong ‘pro-conspiracy’ mindset from the outset, and not among those with an intermediate conspiratorial mindset. Although these results generally support the idea that encouraging people to deliberate can help to counter the growth of novel conspiracy theories, they also indicate that the effect of deliberation on conspiratorial beliefs is more complicated than previously thought.