Judging the frequency or probability of events by how easily examples come to mind, leading to overestimation of vivid, recent, or emotional events.
System 1 assesses frequency by ease of recall: if examples come easily to mind, we assume the category is common. This works when memorable events are actually frequent, but fails when vivid, recent, or emotional events are overrepresented in memory. After seeing news coverage of plane crashes, people overestimate aviation risk and choose to drive instead, even though driving is statistically more dangerous. The heuristic makes us vulnerable to media-driven panics and explains why we overestimate dramatic risks while underestimating mundane ones.
Doctors who recently saw a rare disease diagnose it more frequently in subsequent patients. People overestimate terrorism risk after media coverage but underestimate heart disease risk despite it being far more common.
If you can easily think of examples, the event must be common—in reality, ease of recall reflects memorability (vividness, recency, emotion) not actual frequency.
Why does the availability heuristic lead to overestimation of dramatic risks like terrorism while underestimating mundane risks like heart disease?
True or False: If you can easily think of examples of something, it's probably common.
Logically equivalent choices produce different decisions when framed differently (as gains vs. losses, or with different reference points).
PrincipleContinuing an endeavor because of previously invested resources (time, money, effort) that cannot be recovered, even when continuing is irrational.
PrincipleFast, automatic, unconscious cognitive processing that operates through pattern recognition and associative memory without deliberate effort.
Mental ModelSlow, effortful, conscious cognitive processing required for complex calculations, unfamiliar tasks, and deliberate reasoning.
Mental ModelThe tendency to rely too heavily on the first piece of information encountered (the anchor) when making decisions, even when it's arbitrary or irrelevant.
PrincipleJudging probability by similarity to stereotypes or prototypes, while ignoring base rates and sample size.
PrincipleWhen faced with a difficult question, System 1 automatically substitutes an easier question without conscious awareness of the switch.
FrameworkLosses hurt approximately twice as much as equivalent gains feel good, making people risk-averse for gains and risk-seeking for losses.
PrincipleJudging the frequency or probability of events by how easily examples come to mind, leading to overestimation of vivid, recent, or emotional events.
Doctors who recently saw a rare disease diagnose it more frequently in subsequent patients. People overestimate terrorism risk after media coverage but underestimate heart disease risk despite it being far more common.
If you can easily think of examples, the event must be common—in reality, ease of recall reflects memorability (vividness, recency, emotion) not actual frequency.
Availability Heuristic is explored in depth in "Thinking, Fast and Slow" by Daniel Kahneman. Distilo provides a deep AI-powered analysis with key insights, audio narration, and practical frameworks.