What is Belief updating?
Belief updating is the broader psychological process of revising one’s beliefs in response to new information, encompassing both rational Bayesian updating and the systematic biases that cause people to deviate from it.
How it works
Research shows that people update beliefs asymmetrically: they incorporate desirable information more readily than undesirable information (optimism bias in updating). Sharot et al. (2011) demonstrated that people hearing that cancer risk is lower than they estimated updated their beliefs significantly, while those hearing it was higher showed minimal updating. Belief updating is also influenced by source credibility, emotional state, and whether the new information threatens identity-relevant beliefs.
Applied example
A smoker who learns their specific genetic variant reduces lung cancer risk updates this belief readily. The same smoker who learns their family history increases risk shows less belief updating, because the information is threatening.
Why it matters
Understanding the biases in belief updating explains why correcting misinformation is so difficult and why simply presenting facts often fails to change minds.
