Belief perseverance

Belief perseverance is a cognitive bias in which people maintain a belief even after the evidence that originally supported it has been completely discredited. Once an idea takes root, showing that its foundation was false often fails to dislodge it — the belief persists on its own.

The classic demonstrations come from debriefing studies. Participants were given feedback suggesting they were unusually good (or bad) at a task, formed beliefs about their ability, and were then told the feedback had been fabricated. Even after this full debriefing, their self-assessments continued to reflect the phony feedback. The usual explanation is that people generate their own supporting reasons for a belief — "I probably am good at this because..." — and those self-generated explanations survive even when the original evidence is withdrawn.

Belief perseverance is related to, but distinct from, confirmation bias. Confirmation bias describes how we search for and interpret new information in ways that favor what we already believe; belief perseverance describes hanging on to a belief after its evidence is destroyed. Together they help explain why misinformation is hard to correct, why first impressions are sticky, and why debunking alone rarely changes minds. The most effective countermeasure identified in research is to consider the opposite — deliberately generate explanations for why the contrary belief could be true.

Belief perseverance is a named term on the AP Psychology exam, appearing in units on cognition and social psychology, and the MCAT's psychological, social, and biological foundations section tests it among the cognitive biases that shape thinking and attitude formation. Be ready to distinguish it from confirmation bias in a vignette.