Cognitive Biases — Availability heuristic

Judging situations based on recall rather than fact

Michael Gearon
5 min readNov 4, 2018
Kelly Sikkema — Unsplash

The availability heuristic is a type of bias where people make a decision or a judgement based ease of retrievability and recall. The idea is if a person can recall something quickly then it must be important. For our brains it’s a shortcut to make conclusions with little mental effort or strain.

“The attention which we lend to an experience is proportional to its vivid or interesting character; and it is a notorious fact that what interests us most vividly at the time is, other things equal, what we remember best.”
— William James from the book The Principles Of Psychology

The mechanics of the availability heuristic

Think about a time when you’ve made a decision. Consider how previous influences or events have shaped that decision and, when considering an action to take, how memorable events jump to the forefront of your mind.

When something instantly jumps into your mind this can heavily influence your decision-making abilities. Like with most biases, the pioneers in this area were Amos Tversky and Daniel Kahneman. In Thinking Fast and Slow, Kahneman writes:

People tend to assess the relative importance of issues by the ease with which they are retrieved from memory — and this is largely determined by the extent of coverage in the media.

In one experiment conducted by Tversky and Kahneman, subjects were presented with several letters from the alphabet. They were asked to judge whether each of these letters appeared more frequently as the first or third letter in a word.

The letters, K, L, N, R and V, all occur more frequently as the third letter in English words.

In every case, subjects believed that the letters occurred more frequently in the first position, by a ratio of approximately 2:1.

Photo by Jelleke Vanooteghem on Unsplash

Kahneman and Tversky believed this occurred because it was far easier to recall words that started with a particular letter as opposed to words with a letter in the third position. That is, these “first position” words were more “available” to the subjects.

As part of this same research, Kahneman and Tversky conducted an additional experiment. The subjects were split into two groups and asked to listen to a tape recorded list of 39 names.

For one group, the list contained 19 famous male names and 20 less famous female names. For the other group, the list contained 19 famous female names and 20 less famous male names.

Out of 86 participants, only 13 recalled a greater number of less famous names. Out of 99 subjects, 80 believed that their tape recorded list contained more famous than less famous names.

Again, Kahneman and Tversky concluded that ease of recall led people to miscalculate the frequency of a scenario.

Designing better products

How does the availability heuristic help me design better products or market the product? Well, with this bias in mind, we should aim to create something memorable, especially at the start of a journey, like a landing page, and then another memorable experience at the end of the journey, this could be an order confirmation page.

Karlsson, Loewenstein, and Ariely (2008) showed that people are more likely to purchase insurance to protect themselves after a natural disaster they’ve just experienced than they are to purchase insurance on this type of disaster before it happens.

UK Lottery Promotional Banner

Another example of how companies use the availability heuristic is where lottery companies are employing the availability heuristic when they remind us of recent winners. We subsequently overestimate our own likelihood of winning and divert money towards the purchase of lottery tickets.

Looking at the above example that “Miss P” from London just won £100,00 and that I could be next. Technically it’s true, but what is the likelihood I would be?

More often than not it’s reported on social media, news sites and through marketing that this couple or person are now richer than a celebrity because they won the lottery.

Photo by David Clode on Unsplash

But if you try and recall a time when you’ve seen the opposite, where millions of people have not won the lottery, it would be very difficult. This is the availability heuristic being used, as we’re judging situations and probabilities on the basis of how easily examples come to mind.

The same applies to shark attacks. We are exposed from a young age that shark attacks happen and we must be careful. However, do you know how many shark attacks happen each year? Realistically, what is the probability it will happen to you?

What we have to remember is our memory has limitations. If we create or market products that have a powerful narrative, it improves the ease of recall for people. When it comes to winning the lottery, or that person who won a competition against the odds, these stories are more unique. They stand out and therefore we believe it’s more likely to happen to us because we remember it so clearly.

When creating products we often look towards what other competitors are doing — “competitor research”. We take bits from their website as “inspiration” but we walk blindly into this; we don’t know for sure that what they’re doing is actually good marketing or a mistake.

Instead of relying on competitor research, make your own informed decisions, think about your customers and what their needs are. Do spilt tests, customer feedback and use other ways to collect data instead of relying on guesswork.

The conclusion of all this is to not rely on memories alone, but use facts and figures to make reasoned decisions. Consider the odds if you entered the lottery this evening or decided to do something on pure ‘chance’ — what’s the likelihood that you will come out on top?

If you’re designing products, think about how your customers will interact with your product. Create an intuitive journey people will remember, with particular emphasis on the start and finish of that journey as these points will stick the most clearly in people’s minds.

Further reading



Michael Gearon

Senior Interaction Designer and Co-Author to Tiny CSS Projects