People seek, notice, and recall evidence that fits what they already believe, and set the rest aside.
In Wason's 1960 rule-discovery task, many participants generated tests expected to fit their current hypothesis rather than tests designed to rule it out; only six of twenty-nine reached the correct rule without first announcing an incorrect one.
In practice
- An analyst convinced a supplier is unreliable notices every late delivery and codes the early ones as luck.
- A manager who has decided a hire was a mistake reads their next four pieces of work as confirmation.
- Further reading
- Wikipedia
- Subject
- Decision-making & Reasoning
- Essay
- The catalogue of predictable errors