The conspiracy-effect describes the finding that mere exposure to popular conspiracy theories can have a negative impact on pro-social decision-making and acceptance of established scientific principles. The term “conspiracy-effect” was coined by Sander van der Linden, a social-psychologist at Cambridge University. The conspiracy-effect refers to the idea that conspiracy theories are “sticky” and that even brief exposure to conspiratorial thinking may be sufficient to decrease civic engagement and cooperation in real-life social dilemmas, such as charitable giving, childhood vaccinations, support for actions that help reduce global warming and intentions to vote.
The finding is largely based on the fact that although public endorsement of popular conspiracy theories is growing, the majority of contemporary conspiracy theories lack credibility and scientific support and often propagate false information and harmful narratives. For example, recent research has found that espousal of some conspiracy theories may promote racist attitudes and political violence.
Research by Stephan Lewandowsky and colleagues has shown that belief in conspiracy theories is associated with the “motivated rejection of science”, including denial of the link between aids and HIV, smoking and lung cancer and CO2 emissions and global warming. Similar research has found that having people read articles about a particular conspiracy theory decreases inclinations to perform civic duties, such as intentions to vote and vaccinate.