Chapter 12 - The science of availability

The science of availability 

Availability heuristic = the process of judging frequency by “the ease with which instances come to mind”. Both systems are involved.

It is a heuristic of judgement which substitutes one question for another: you wish to estimate the size of a category/frequency of an event, but you report an impression of the ease with which instances come to mind. It is indeed a systematic error which can lead to biases.

How to realize that it creates a bias?

You have to make a list of factors that are not frequency that make it easy to come up with instances. Each of these factors will be a potential source of bias.

Examples:

è  A striking event will be easily be remembered. Divorces among Hollywood celebrities and sex scandals among politicians attract a lot of attention. Indeed, you will have many examples of it. Therefore, you will be likely to exaggerate the frequency of Hollywood divorces and political sex scandals

è  If a dramatic event occurs, it will increase the availability of this category. If you see a plane crash on the news, massively covered by media, you will think more about accidents and lack of security, and if you see another car accident, you will think for a while that the world is a dangerous place.

You can fight again this bias but it takes a lot of energy. You have to reconsider your impressions and intuitions. “Do I think that teenagers committing thefts is a major problem because there are many instances of it in my neighbourhood?”

Many studies have proved that it is a good thing to be aware of your own biases because it can solve many issues in relationships or in marriage for example.

è  Study of spouses who were asked about their personal contribution to keep the house tidy: availability bias because you remember much more your own efforts. It leads to a difference in judged frequency.

Another question: How the number of instances retrieved and the ease with which they come to mind affect your judgment?

It appears that self-ratings are dominated by the ease with which examples come to mind. The experience of fluent retrieval of instances is more powerful than the number of examples retrieved.

è  Study of people self-assessment as assertive

BUT judgments are no longer influenced by ease of retrieval when the experience of fluency is given a spurious explanation (music making much harder to remember).

Link with system 1 and 2:

The ease with which instances come to mind is part of system 1, which is replaced by a focus on content when system 2 is more engaged. People who let themselves be guided by system 1 are more susceptible to availability bias than they other who are more vigilant.

Examples of availability biases:

·       “Because of the coincidence of two planes crashing last month, she now prefers to take the train. That’s silly. The risk hasn’t really changed; it is an availability bias.”

·       “She has been watching too many spy movies recently, so she’s seeing conspiracies everywhere.”

·       “The CEO has had several successes in a row, so failure doesn’t come easily to her mind. The availability bias is making her overconfident.”