What makes people believe in conspiracy theories?

Conspiracy belief is not a marker of stupidity. It is produced by cognitive habits that are useful in general and misfire in specific conditions. Intelligent, educated people hold conspiracy beliefs at substantial rates, and intelligence mostly changes which ones.

Understanding it as ordinary psychology is both more accurate and more useful than treating believers as unusual.

Humans are built to find patterns in noise and intention behind events, because historically the cost of missing a real threat exceeded the cost of a false alarm. That bias produces constellations in random stars and plots in random events.

It is the same faculty that makes good detectives and good scientists. It simply has no automatic off switch.

People expect large effects to have large causes. A world-altering event caused by one unremarkable person, or by an accident, feels unbearable in a way that a vast plot does not.

A conspiracy restores proportion. It is, oddly, a comforting story: terrible things are at least being decided by someone.

Belief rises during crises, job insecurity and social upheaval. It also rises among people with real experience of institutions failing or lying to them — which is why communities with documented histories of being mistreated are more sceptical, reasonably so.

Knowing something others do not also supplies status, which is a genuine reward the belief keeps paying.

Recognise the pull in yourself rather than only in others. Notice when an explanation is attractive because it restores order rather than because it fits evidence.

And when talking to someone who believes, address the underlying worry — powerlessness, mistrust, fear — rather than only the factual claim. Facts alone almost never move a belief that is doing emotional work.