Two salient but unrelated things are remembered as co-occurring, creating a relationship that is not there.
Chapman and Chapman's 1967 work on projective tests: clinicians reported diagnostic signs that were not in the data, because the pairing was memorable rather than frequent.
In practice
- A manager remembers that the two worst incidents both happened after a particular engineer's deploys, and has forgotten the eleven that did not.
- A parent is certain a food causes their child's bad nights, having noticed the coincidences and not the counter-instances.
- Further reading
- Wikipedia
- Subject
- Decision-making & Reasoning
- Essay
- The catalogue of predictable errors