Why do conspiracy theories exist?

Listener Avalon from Australia wants to know why people use conspiracy theories to explain shocking events. Are we more likely to believe conspiracy theories in times of adversity? What purpose do conspiracy theories serve in society?

Marnie Chesterton speaks to the scientists to explain their popularity, even in the face of seemingly irrefutable evidence.
Presented by Marnie Chesterton. Produced by Caroline Steel for the BBC World Service.

Image: All-seeing eye of God inside triangle pyramid. Credit: paseven, Getty Images