Hard-Easy Effect
Discriminability Effect · Difficulty Effect
The tendency to be overconfident on hard tasks and underconfident on easy ones. We overestimate our chances when things look difficult, and underestimate them when things look simple.
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Origin
Documented in calibration research by Fischhoff, Slovic, and Lichtenstein in the 1970s and 1980s. They found a systematic pattern: when people answered difficult trivia questions, they were more confident than their accuracy warranted; for easy questions, they were less confident than they should have been. The effect has been replicated across domains from general knowledge to medical diagnosis.
Updated February 22, 2026