Availability heuristic
Judging how likely something is by how easily an example comes to mind.
1 min read
Reviewed by Shariq Refai, MD, MBA, FAPA. Verify: ORCID, Wikidata, NPI Registry, all links.
The availability heuristic is a shortcut the brain uses to answer questions about probability. Instead of doing the math, it asks how quickly an example jumps to mind. Fast and vivid examples feel likely. Slow and boring ones feel rare. This works well often enough that we keep using it, and misfires badly enough to matter.
Where it shows up
Vivid events feel common
Plane crashes make news, so people overestimate flight risk. Car crashes rarely make the news, and people underestimate driving risk. Available beats accurate.
Recent events feel typical
The last thing that happened to you or someone you know feels like the base rate. One recent breakup can make relationships in general look doomed.
Personal experience outweighs data
A single stark story about a medication side effect can outweigh a clean safety profile. The story is available. The statistics are not.
In health anxiety
Hearing about a rare disease brings it to mind easily, and the symptoms you already have suddenly seem to point at it. Availability, not evidence, is doing the work.
In social judgment
You judge how a group behaves by the loudest examples you have encountered. Loud is available. Typical is not.
How to use this page
- When something feels obviously likely, ask what the base rate actually is. Look it up rather than trust the mental sample.
- When a story is vivid, notice that. Vividness is not evidence.
- In big decisions, count how many examples you actually have. Two loud ones do not out-vote a hundred quiet ones.
Worth knowing
The availability heuristic is not a flaw. It is a fast-and-frugal way to make decisions in a world without unlimited time. The correction is not to stop using it. It is to notice when the answer matters enough to slow down and check.
Introduced by Amos Tversky and Daniel Kahneman in 1973. One of the foundational ideas of modern behavioral science.
See also on ShrinkDaily
- ShrinkDaily's daily concept on availability heuristic
For a three-minute daily read on the same idea, see ShrinkDaily's daily concept on availability heuristic.
How to cite this page
- Short
Availability heuristic. Shrinkopedia, medically reviewed by Shariq Refai, MD, MBA. https://shrinkopedia.com/library/availability-heuristic/- APA
Shrinkopedia. (n.d.). Availability heuristic. Medically reviewed by Shariq Refai, MD, MBA. https://shrinkopedia.com/library/availability-heuristic/- MLA
"Availability heuristic." Shrinkopedia, https://shrinkopedia.com/library/availability-heuristic/.
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