Joachim Andersen

Accelerated Learning

Availability Heuristic: Why Vivid Examples Distort Our Sense of Risk

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A wide antique brass bowl of dull dark grey stone marbles with one large polished gold sphere on top catching a warm spotlight on a dark walnut desk at night
The one that shines is not the one that is most common.


The Availability Heuristic is the mental shortcut of judging how common or likely something is by how easily examples come to mind. If we can quickly think of several cases, we assume the thing must be frequent. If we struggle to think of any, we assume it must be rare.

Most of the time, this works well enough. Things that happen often are usually easier to remember. But memory is also shaped by what is recent, vivid, emotional or widely reported, and none of those have much to do with how often something actually happens.

We typically notice it most after reading the news. A single dramatic story can make a danger feel close and common for weeks, while much bigger risks that never make headlines hardly cross our mind. The same thing happens at work, where the last mistake someone made can shape our view of them more than years of solid work.

The essence of the Availability Heuristic is to ask: “Is this really common, or is it just easy to remember?”


Origin: The Letter K

The term was introduced by Amos Tversky and Daniel Kahneman in a 1973 paper in Cognitive Psychology. In one of their best-known demonstrations, they asked people whether a letter such as K is more likely to appear as the first letter of a word or as the third. Most people answered the first position, because words starting with K are much easier to bring to mind (and it’s more complex to think about word with a certain letter in the third “spot”), even though K actually appear more often in the third position.

In another experiment, participants listened to a list of 39 names. Some lists had 19 famous women and 20 less famous men, and others had 19 famous men and 20 less famous women. Afterwards, most participants incorrectly judged that the gender with the more famous names had been more frequent on the list. The famous names were easier to recall, so they seemed more numerous.


Key Concepts

  • Ease as Evidence
    We use the feeling that something is easy to recall as a signal of how common it is.

  • Vividness
    Dramatic, emotional and concrete events are remembered far better than dull statistics, so they feel more likely.

  • Recency
    Something that happened recently is easier to recall, so its probability feels higher right after it happens.

  • Media Amplification
    What gets reported is what is unusual, so news coverage can make rare events feel common.

  • Ease vs. Amount
    What matters is often not how many examples I can recall, but how easy it feels to recall them. If recalling is hard, I may conclude the opposite of what my examples suggest.

  • Personal Experience
    What has happened to us or people we know weighs more heavily than what happens to strangers.


Some Examples

  • The Twelve Examples
    In 1991, Norbert Schwarz and his colleagues asked students to describe either 6 or 12 situations in which they had behaved assertively. Recalling 6 was easy and recalling 12 was difficult. Those who described 12 assertive situations rated themselves as less assertive than those who described only 6, even though they had just listed more evidence. The feeling of difficulty mattered more than the content. In fact, those asked for 12 examples of unassertive behavior rated themselves as more assertive than those asked for 12 assertive ones(!)

  • Driving Instead of Flying
    After the attacks of September 11, 2001, many Americans avoided flying and drove instead. In 2004, Gerd Gigerenzer analyzed the traffic data for the following three months and concluded that the number of people who died on the roads by avoiding the risk of flying was higher than the total number of passengers killed on the four hijacked planes(!) A vivid, terrifying image made flying feel more dangerous than the much more ordinary risk of driving.

  • The Burglaries on My Street
    After a neighbor told me about a break-in, I suddenly felt that burglaries were everywhere. I double-checked the locks and started noticing every unfamiliar car. Nothing had changed except that one story was fresh in my mind.

  • The Last Project I Remember
    When I estimate how long a new project will take, I tend to remember the last project I worked on, or the one that went unusually well or badly. That single memory often shapes my estimate more than the average of all the projects I have done.


Applying the Availability Heuristic

I can’t stop my mind from using what is easy to recall, but I can check it before it drives an important judgment. This is the simple process I follow:

  1. Notice the Trigger
    When something feels very likely, I ask whether I have recently seen, heard or read about it.

  2. Look for the Numbers
    I look up base rates and statistics instead of relying on the examples I can remember, as I describe in Probabilistic Thinking.

  3. Compare Like with Ordinary Risks
    I compare the risk I am worried about with the ordinary risks I accept every day without thinking, such as driving, and ask which one is actually larger.

  4. Widen the Sample
    I deliberately recall cases that are less memorable, such as all my past projects and not just the most recent one.

  5. Discount the Story
    A vivid story is a reason to look for data, not a substitute for it, as I describe in Narrative Fallacy.


Pitfalls and Limitations

  • Availability is often a useful guide. Things I encounter a lot are usually common, and in a familiar environment, the shortcut can be fast and accurate.

  • Some findings are less robust than they seem. In 2021, Roy Groncki, Jennifer Beaudry and James Sauer tried and failed to replicate the original ease-of-retrieval finding by Schwarz and colleagues.

  • Real-world estimates are uncertain. In 2011, Raywat Deonandan and a colleague used a different method and did not confirm a statistically significant increase in traffic deaths after September 11, 2001.

  • Knowing about the bias does not remove it. Even when I know that a story is unrepresentative, it can still change how I feel about the risk.

  • Others can use it on me. Advertisers, campaigners and media outlets know that a repeated, vivid example is more persuasive than an accurate statistic, so I try to notice when a story is being used to make a point.


Related Mental Models

The Availability Heuristic reminds me that what comes to mind easily is not the same as what happens often. By noticing when a recent or vivid example is driving my judgment, and checking it against the numbers, I can keep my sense of risk closer to reality.



To learn more about mental models and philosophy,
check out: Wise: How to Attain a Deep Understanding of the World, History, Our Place in It, and How to Live Well



📚 Sources and References


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