Belief perseverance

Belief perseverance (also known as conceptual conservatism) is maintaining a belief despite new information that firmly contradicts it. Such beliefs may even be strengthened when others attempt to present evidence debunking them, a phenomenon known as the backfire effect (compare boomerang effect). For example, in a 2014 article in The Atlantic, journalist Cari Romm describes a study involving vaccination hesitancy. In the study, the subjects expressed their concerns of the side effects of flu shots. After being told that the vaccination was completely safe, they became even less eager to accept them. This new knowledge pushed them to distrust the vaccine even more, reinforcing the idea that they already had before.

There are three kinds of backfire effects: Familiarity Backfire Effect (from making myths more familiar), Overkill Backfire Effect (from providing too many arguments), and Worldview Backfire Effect (from providing evidence that threatens someone’s worldview). According to Cook & Lewandowsky (2011), there are a number of techniques to debunk misinformation, such as emphasizing the core facts and not the myth, or providing explicit warnings that the upcoming information is false, and providing alternative explanations to fill the gaps left by debunking the misinformation. However, more recent studies provided evidence that the backfire effects are not as likely as once thought.

Since rationality involves conceptual flexibility, belief perseverance is consistent with the view that human beings act at times in an irrational manner. Philosopher F.C.S. Schiller holds that belief perseverance "deserves to rank among the fundamental 'laws' of nature".