People judge frequency or probability by how easily instances come to mind. If examples are retrievable, the class feels numerous — a useful clue that becomes biased when retrieval is driven by factors other than frequency.
What skews availability
- Salience: a house fire on the highway raises perceived accident risk
- Recency: recent events overweight the past
- Fame: lists where men were more famous were judged to have more men than women lists where women were more famous
- Emotion: dread risks (plane crashes, terrorism) dominate statistics (stroke, diabetes)
Availability drives media-shaped fears, hot-hand beliefs (Gilovich: basketball streaks are random), and CEO reputation from vivid outcomes rather than base rates.
Relation to substitution
The question "how risky is X?" is often answered by "how easily can I recall bad outcomes of X?" — a substitution pattern.
Sources
- thinking-fast-and-slow
- fooled-by-randomness — vividness and narrative overweight noise