The proportionality bias is the tendency to assume that significant events are caused by equally significant factors. This cognitive bias leads people to believe that major occurrences, such as natural disasters or historical events, must have large or elaborate causes. It plays a role in the acceptance of conspiracy theories, as individuals find it difficult to reconcile the idea that a small cause could lead to a monumental effect.
For instance, the widespread belief that Princess Diana's tragic car accident was the result of a conspiracy stems from the proportionality bias, as many find it hard to accept that such a major public figure could die from what seems like a mundane accident.
To overcome the proportionality bias, it is essential to consciously evaluate the evidence for causes of major events and consider that significant outcomes can stem from small random factors. Engaging critically with information and seeking diverse perspectives can also help counteract this bias.