Van Prooijen, J.-W., & Van Vugt, M. (in press). Conspiracy theories: Evolved functions and psychological mechanisms. Perspectives on Psychological Science.


Belief in conspiracy theories—such as that 9/11 was an inside job, or that the pharmaceutical industry deliberately spreads diseases—is a widespread and culturally universal phenomenon. Why do so many people around the globe believe conspiracy theories, and why are they so influential? Previous research focused on the proximate mechanisms underlying conspiracy beliefs, but ignored the distal, evolutionary origins and functions. We review evidence pertaining to two competing evolutionary hypotheses: (a) conspiracy beliefs are a byproduct of a suite of psychological mechanisms that evolved for different reasons (pattern recognition; agency detection; threat management; alliance detection); or (b) conspiracy beliefs are part of an evolved psychological mechanism specifically aimed at detecting dangerous coalitions. This latter perspective assumes that conspiracy theories are activated following specific coalition cues, which produce functional counterstrategies to cope with suspected conspiracies. Insights from social, cultural and evolutionary psychology provide tentative support for six propositions that follow from the adaptation hypothesis. We propose that people possess a functionally integrated mental system to detect conspiracies that in all likelihood has been shaped in an ancestral human environment in which hostile coalitions—that is, truly existing conspiracies—were a frequent cause of misery, death, and reproductive loss.