Examining the Availability Heuristic

The availability heuristic is when people predict the frequency of an event based on how easily an example can be brought to mind.

fig. 1

Risk of Death vs Cause

Availability heuristics shape the way we view our world. Although you are significantly more likely to die in an auto accident (1 in 6,029) than you are to die in a terrorist attack (1 in 97,927), in light of the recent media attention about terrorist activity, people falsely believe due to the availability heuristic that terrorist attacks are more eminent.

KEY POINTS

We are more likely to respond to an event the more recent the memory of its occurrence is. So if something happens often or frequently enough, it will come to mind effortlessly and vividly, making it appear more available.
Another way that we tend to respond quickly with solutions is when we use theavailability heuristic to estimate the likelihood of an event occurring again based on whether a similar event has occurred previously.
One important corollary finding to this heuristic is that people asked to imagine an outcome tend to immediately view it as more likely than people who were not asked to imagine the specific outcome.

TERMS

Availability heuristic
A mental shortcut that uses the ease with which examples come to mind to make judgments about the probability of events.

EXAMPLES

The news can affect our availability heuristic by producing vivid memories that are more readily available. For instance, if the news has recently reported on large forest fires, we are more likely to believe that forest fires are on the rise because the memory appears vivid and is readily available.

The availability heuristic is a phenomenon (which can result in a cognitive bias) in which people predict the frequency of an event, or a proportion within a population, based on how easily an example can be brought to mind. This phenomenon was first reported by psychologists Amos Tversky and Daniel Kahneman, who also identified the representativeness heuristic.

Essentially, the availability heuristic operates on the notion that "if you can think of it, it must be important." Media coverage can help fuel a person's example bias with widespread and extensive coverage of unusual events, such as homicide or airline accidents, and less coverage of more routine, less sensational events, such as common diseases or car accidents.

For example, when asked to rate the probability of a variety of causes of death, people tend to rate more "newsworthy" events as more likely because they can more readily recall an example from memory (Figure 1). To this point, people rate the chance of death by homicide higher than the chance of death by stomach cancer, even though death by stomach cancer is five times more common than death by homicide. Another instance of biased ratings is the relative overestimation of plane crash deaths compared to car accident deaths.

One important corollary finding to this heuristic is that people asked to imagine an outcome tend to immediately view it as more likely than people who were not asked to imagine the specific outcome. If group A were asked to imagine a specific outcome and then asked if it were a likely outcome, and group B were asked whether the same specific outcome were likely without being asked to imagine it first, the members of group A tend to view the outcome as more likely than the members of group B. This result demonstrates the tendency toward using an availability heuristic as a basis for logic (Caroll, 1978).

The content of this page is licensed under a Creative Commons Attribution Share-Alike License except for any elements that may be licensed differently. The content of this page includes:

Examining the Availability Heuristic was created by Boundless under a Creative Commons Attribution Share-Alike License
Original content contributed by Lumen Learning

If you believe that a portion of this Open Course Framework infringes another's copyright, contact us.

Boundless curates and validates high quality, openly licensed content from around the Internet. This particular unit used the following sources: