Judgment under Uncertainty: Heuristics and Biases

Judgment under Uncertainty: Heuristics and Biases

Amos Tversky and Daniel Kahneman. 1974. (View Paper → )

When we make calls under uncertainty we lean on three shortcuts:

• Representativeness - Judging probability by similarity to stereotypes, often ignoring statistical factors like base rates
• Availability - Estimating frequency based on how easily examples come to mind, making recent or memorable events seem more common
• Anchoring - Starting with an initial reference point that biases final estimates, even when that anchor is arbitrary

They are fast but they reliably skew our judgment (base-rate neglect, overconfidence from tiny samples, and anchoring on the first number we see).