Conspiracy in the pub

Dr Daniel Jolley (Staffordshire University) opened a fascinating Psychologists in the Pub talk at the Gunmakers Arms in Birmingham with evidence conspiracy theories are on the rise. Despite the often-held view that such theories are believed by only a small number of people, Jolley remarked that around 20 per cent of people believe Princess Diana was assassinated.

The internet may be partly responsible for making these beliefs more widespread. Jolley pointed out that the first hit on Google for the question 'Should I vaccinate my child?' is a so-called anti-vax website.

But why do people believe in them? Jolley said certain cognitive shortcuts could partly explain this belief.

For example, he said, the proportionality bias causes us to point to large causes for large events, rather than accepting more mundane explanations. For example, JFK's assassination led to scores of conspiracy theories, while the attempted assassination of Ronald Reagan did not – if it had been, might there have been such theories surrounding his death too?

People who believe in one conspiracy believe in several others, but they sometimes believe in contradictory theories. Jolley pointed to the killing of Osama bin Laden – some believe theories that say he is dead and at the same time think he may still be alive. He explained that this points to a higher-order belief system and said: 'If you endorse the belief that the US is hiding important information it doesn't matter what the theory is as long as it meets the essential viewpoint that they're hiding something.'

As Jolley pointed out, many people hold this sort of belief, but are these theories harmless and interesting or more sinister? He gave evidence that the belief that HIV and AIDs are manmade is related to a more negative attitude towards condom use, and that a larger belief in such theories makes a person more likely to potentially avoid treatment for HIV. 

Jolley's own research has asked 89 British parents to fill in a questionnaire asking about their belief in anti-vaccine conspiracy theories and then indicate their vaccination intention for a child against a fictional disease. He found those with higher belief in conspiracy theories indicated a lower intention to vaccinate their child – adding proof to his theory that conspiracy theories may translate into real-world harm.

In a second experiment, participants were either exposed to material endorsing conspiracy theories or a more mainstream account that vaccines are safe. He saw that those exposed to conspiracy accounts had a higher belief in anti-vaccine conspiracies, these people also indicated less intention to vaccinate. Another study found that exposure to government conspiracies leads to less intention to engage with politics and a lower likelihood of voting.

Jolley also looked into the role of conspiracy theories in changing perceptions of social groups. In ongoing work, he found being exposed to conspiracy theories about Jewish people leads to more negative feelings towards this group and makes people less likely to vote for them in a fictional European Parliament election. He concluded: 'Conspiracy theories don't just have negative practical influences but can also change how you see other people and as a result could impact on group relations.'