Availability bias

The availability bias is a cognitive bias involving making quick judgments based on the speed with which memories are aroused and become available to the conscious mind. The main factors influencing the speed with which memories present themselves are recent frequency of similar experiences or messages, or the salient, dramatic, or personal nature of experiences. In our culture, the mass media plays an important role in affecting what comes to mind quickly when we think of the frequency, importance, or causes of things. Rational judgments should be made on the basis of a consideration of all the relevant evidence, but many judgments we consider rational are made based on the ease with which they come to us.

For example, a person might decide not to take a cruise to Alaska that she was about to book when she heard about the cruise ship Costa Concordia striking a reef hear the Tuscan island of Giglio, killing more than 20 passengers. The safety of a cruise to Alaska has not diminished because of what happened off the coast of Italy, but the news report and videos immediately bring to the mind the horror of dying on a capsized cruise ship. The decision not to take the planned cruise has been biased by the news of the Costa Concordia. Likewise, many people refuse to fly on a commercial airliner because someone they love died in an airplane crash, yet these same people will drive thousands of miles every year rather than fly, even though they are more likely to be killed in an automobile crash than in an airliner crash.

When asked for your opinion on teenage drug use, premarital sex, morals of politicians, good stocks to invest in, the incidence of violent crime, or any other subject that mass media outlets are likely to cover, the odds are that your answer will be based on what comes immediately to mind and that will be heavily influenced by what you´ve read, seen, or heard recently in the mass media. Or, your answer will be heavily influenced by personal experience. What is unlikely is that your opinion will be based on objective or scientific knowledge of the subject.

This tendency to make judgments by the ease with which ideas come to mind is called the availability heuristic. Scientific studies have shown that certain kinds of personality traits make one more susceptible to the availability bias. Scwartz et al. found that people who have great faith in intuition and people who are powerful (or made to feel powerful) tend to be affected more strongly by ease of retrieval than by the content they retrieve, if indeed they even bother with much content.

The way to mitigate the availability bias is to be aware of it and to take the necessary steps to get good data before making a judgment. For example, try to be aware that when the first thing evoked in memory is a stereotype (see Representativeness bias) or is accompanied by very pleasant feelings, it becomes more difficult to overcome the availability bias.

The availability bias is a central issue in my book A Portrait of a Lifeartist.

Excerpt from

A Dictionary of Thought Distortions

Copyright © 2014 by Morten Tolboll