The Science of Changing Your Mind

Changing one's mind in response to evidence is held to be a virtue, yet it is among the rarest of behaviours in public life. Politicians are routinely attacked for it — the label "flip-flopper" is used as a term of condemnation rather than description. This is a remarkable inversion, given that the capacity to update beliefs in light of new information is precisely what we consider rational.

Cognitive scientists have documented the mechanisms that make belief change difficult. Confirmation bias — the tendency to seek out and weight evidence that confirms existing beliefs — is among the most robust findings in the field. It operates not by making people irrational but by shaping what information they encounter and how they process it. The result is that people can be exposed to the same evidence and reach different conclusions, not because of different reasoning capacities but because of different prior beliefs that determine what counts as relevant.

A related phenomenon is the "backfire effect" — the finding, initially reported in 2010, that corrections to false beliefs sometimes make those beliefs more entrenched. Subsequent research has partially replicated and partially complicated this finding, suggesting that the effect is less universal than initially claimed, but that motivated reasoning — reasoning in service of reaching a predetermined conclusion — is real and pervasive.

What does seem to support belief change is a combination of factors: trust in the source of the new information, social permission to change — the sense that updating will not involve unacceptable costs to one's identity or community — and explicit acknowledgement of the new evidence's quality. None of these is primarily a matter of intelligence. They are matters of context and relationship, which is why individual-level explanations of motivated reasoning are often insufficient.