From Daniel Kahneman “Thinking, fast and slow”
Beware of the Availability Heuristic!
- When you are trying to estimate the frequency of something, you will make an estimate based on how easily you can recall it in your mind. This is called the Availability Heuristic. It’s an illusion!
- “We defined the availability heuristic as the process of judging frequency by “the ease with which instances come to mind.” (p. 129)
- “The world in our heads is not a precise replica of reality; our expectations about the frequency of events are distorted by the prevalence and emotional intensity of the messages to which we are exposed.” (p. 138)
- “The lesson is clear: estimates of causes of death are warped by media coverage. The coverage is itself biased toward novelty and poignancy. The media do not just shape what the public is interested in, but also are shaped by it.” (p. 138)
Examples of the Availability Heuristic:
- You probably think Terrorist attacks happen much more frequently than reality. This is because you can easily recall the attacks in your mind. The media helped give you these vivid images.
- Let’s say you see a plane crash on the news. You will probably think it is more dangerous to fly on a plane than reality.
- Let’s say you see a car burning on the side of the road. You will probably think the world is more dangerous than reality.
- “Personal experiences, pictures, and vivid examples are more available than incidents that happened to others, or mere words, or statistics.” (p. 130)
- “Divorces among Hollywood celebrities and sex scandals among politicians attract much attention, and instances will come easily to mind. You are therefore likely to exaggerate the frequency of both Hollywood divorces and political sex scandals.” (p. 130)
- If you can easily recall friends who had a heart attack at middle age, you probably will think it happens more often than reality.
- “A judicial error that affects you will undermine your faith in the justice system more than a similar incident you read about in a newspaper.” (p. 130)
- Kahneman was wondering what the divorce rate is for professors in his University. He quickly recalled all the professors he knew that were divorced. Kahneman realized he was affected by the Availability Heuristic. Just because he could easily recall the professors who were divorced, does not mean the rate of divorce is high.
- A list of names were given for people to read. Then they were asked if there were more men or women on the list. If the list had some famous male names, the participants said there were more men. If the list had some famous female names, the participants said there were more women.
- “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.”(p. 136)
- “He underestimates the risks of indoor pollution because there are few media stories on them. That’s an availability effect. He should look at the statistics.”(p. 136)“
- “Is our belief that thefts by teenagers are a major problem due to a few recent instances in our neighborhood?” (p. 131)
- “Could it be that I feel no need to get a flu shot because none of my acquaintances got the flu last year?” (p. 131)
- “She has been watching too many spy movies recently, so she’s seeing conspiracies everywhere.”(p. 136)
“One of the best-known studies of availability suggests that awareness of your own biases can contribute to peace in marriages, and probably in other joint projects.”
Spouses were asked these questions:
- How large was your personal contribution to keeping the place tidy, in percentages?
- How large was your personal contribution to taking out the garbage, in percentages?
- How large was your personal contribution to initiating social engagements, in percentages?
- And many other questions.
The spouses answers were recorded. Theoretically, the estimated contributions of both spouses should add up to 100%. Did they?
Usually it added up to more than 100%! It’s not possible that the contributions added up to more than 100%.
Why is this? “The explanation is a simple availability bias: both spouses remember their own individual efforts and contributions much more clearly than those of the other, and the difference in availability leads to a difference in judged frequency.” (p. 131)
“The same bias contributes to the common observation that many members of a collaborative team feel they have done more than their share and also feel that the others are not adequately grateful for their individual contributions.” (p.131)
How Do You Avoid the Availability Heuristic?
- Use statistics and probabilities.
- “”Maintaining one’s vigilance against biases is a chore—but the chance to avoid a costly mistake is sometimes worth the effort. (p. 131)
- “I am generally not optimistic about the potential for personal control of biases, but this is an exception. The opportunity for successful debiasing exists because the circumstances in which issues of credit allocation come up are easy to identify, the more so because tensions often arise when several people at once feel that their efforts are not adequately recognized. The mere observation that there is usually more than 100% credit to go around is sometimes sufficient to defuse the situation.” (p. 131)
- “You must make the effort to reconsider your impressions and intuitions by asking such questions as,
“Is our belief that thefts by teenagers are a major problem due to a few recent instances in our neighborhood?” or “Could it be that I feel no need to get a flu shot because none of my acquaintances got the flu last year?”
Other Notes About the Availability Heuristic:
- When something is easy to recall in your mind, you will be overconfident about it.
- If you can easily recall 3 examples of something, you will be overconfident. If someone asks you to list 12 examples of something and you have a hard time coming up with 12 examples, you will be under confident.
- “The contest yielded a clear-cut winner: people who had just listed twelve instances rated themselves as less assertive than people who had listed only six. Furthermore, participants who had been asked to list twelve cases in which they had not behaved assertively ended up thinking of themselves as quite assertive!” (p. 132)