ABSTRACT
Conspiracy theories explain the ultimate causes of significant events and circumstances as the secret actions of malevolent groups who cover up information to suit their own interests (e.g. Douglas et al. 2017). Well-known conspiracy theories propose that climate change is a hoax orchestrated by the world’s scientists to secure research funding, that Diana, Princess of Wales was murdered by members of the British government and that the harms of vaccines are being covered up so that pharmaceutical companies can continue to make huge profits. Conspiracy theories are popular, and some research suggests that around half of the U.S. population believes at least one (Oliver, Wood 2014). In recent years, psychologists have made significant progress in understanding why so many millions of people believe in conspiracy theories (see Douglas et al. 2017 for a review). However, much less is known about their consequences. In this chapter, we outline what is known to date, and review the psychological research on the positive and negative consequences of conspiracy theories. Overwhelmingly, this research suggests that conspiracy theories are harmful. We, therefore, argue that future research efforts should attempt to address the negative psychological and behavioural consequences of conspiracy theories.
