The availability heuristic is a mental shortcut in which we estimate the likelihood of an event based on how easily examples of it come to mind. If instances are vivid, recent, or frequently discussed, they feel more probable — regardless of what the actual statistics show. If they are hard to recall, they feel rare, even when they are not.

The heuristic was identified and named by Amos Tversky and Daniel Kahneman in their 1973 paper "Availability: A heuristic for judging frequency and probability." Their central finding was that the ease with which examples can be retrieved from memory is a genuinely useful proxy for frequency in many situations — things that happen often do tend to be easier to recall. The problem is that ease of recall is influenced by many factors that have nothing to do with frequency: vividness, emotional impact, recency, media coverage, and personal relevance all make events more memorable without making them more common.

How the Heuristic Distorts Risk Perception

The availability heuristic produces some of the most consistently observed distortions in risk estimation:

• Flying vs driving: Plane crashes receive intense media coverage and are viscerally memorable. Car accidents are statistically far more deadly but individually unremarkable. As a result, many people significantly overestimate their risk of dying in a plane crash relative to a car journey of equivalent distance.
• Shark attacks vs coconuts: Shark attacks are dramatic, newsworthy, and memorable. Deaths from falling coconuts are statistically comparable in some regions but are never reported. Availability, not statistics, drives fear.
• Crime perception: Periods of intense news coverage of violent crime reliably increase public perception that crime is rising, even when crime statistics are falling. Availability — not base rates — shapes the felt sense of danger.
• Lottery and rare events: Extensive media coverage of lottery winners makes winning feel more probable. Hearing no news about the millions who did not win is statistically informative, but it is not memorable.

Why Media and Technology Amplify the Heuristic

The availability heuristic was observed before 24-hour news cycles and social media existed. Those environments have dramatically amplified its distorting effects. Platforms that reward emotional engagement and shareability systematically surface vivid, alarming, and unusual content. This shapes what is available in memory — and therefore what people believe is common, likely, and important.

The result is a significant divergence between perceived and actual risks. Dramatic rare events — terrorism, plane crashes, abductions — consume vastly more mental bandwidth than the genuinely high-probability threats that kill far more people: cardiovascular disease, road accidents, falls in the home.

Availability vs Representativeness

The availability heuristic is sometimes confused with the representativeness heuristic, which judges probability based on how well an example matches a prototype. Both are mental shortcuts that bypass statistical reasoning, and they often operate together. When a scenario is both vivid and matches our mental prototype of a risk category, availability and representativeness compound each other.

How to Counteract the Availability Heuristic

• Seek base rate statistics. When assessing a risk, look for the actual frequency data rather than relying on what comes easily to mind. How many people are actually affected by this event annually? What is the reference class?
• Ask why you remember this. Is this example easy to recall because it is genuinely common, or because it is vivid, recent, or extensively covered? Separating memorability from frequency is the core correction.
• Deliberately search for the invisible cases. If you are estimating how common something is, think about the cases you would not normally hear about — the uneventful flights, the safe crossings, the unremarkable days. These are statistically far more numerous but contribute almost nothing to availability.
• Slow down on decisions involving emotional content. Vivid, frightening, or exciting information is exactly where the availability heuristic is most active and most misleading.

Practise Recognising It

The availability heuristic is one of the most consequential biases in everyday life because it directly shapes how we vote, what we buy, what we fear, and how we invest. Sharpen your recognition in the Dojo and explore how it connects to Confirmation Bias and Survivorship Bias in the Library.