Illusory correlation
Seeing a relationship between two things that aren't actually linked.
What it means
Illusory correlation is the perception of a relationship between two variables — often between membership in a group and some behavior or trait — where no relationship exists or where it is far weaker than believed. The classic mechanism is distinctiveness: when two rare or unusual events co-occur, the pairing is especially salient and over-encoded in memory, so it is later recalled as more frequent than it was, seeding and sustaining stereotypes about minority groups whose members and whose negative acts are both comparatively infrequent. A second route is expectancy-driven: when we already believe two things go together, confirming instances are noticed and remembered while disconfirming ones slip by, so prior theory manufactures the very correlation that seems to confirm it. The effect is robust and helps explain superstition, the persistence of pseudoscientific health claims, and the durability of prejudice even among people exposed to neutral data. It matters because accurate judgment of covariation is foundational to learning what causes what, and illusory correlations quietly substitute a vivid story for the unglamorous base rates.
Examples
People are sure their arthritis pain tracks the weather, vividly recalling the achy rainy days while forgetting the painless ones — though careful studies find no reliable link.
A three-person team's one missed deadline is still being mentioned months later while the eighty-person department's identical slips blur into background noise, and 'that team is unreliable' hardens into fact.
A recruiter is sure graduates of one university underperform, recalling the two who did while the many who thrived leave no trace. The belief quietly filters the evidence that seems to confirm it.
First described in Chapman & Chapman (1967).