# 5.3 Types of Heuristics: Availability, Representativeness & Base-Rate

Did you know that our brain uses strategies to process information and draw conclusions? Although we’re able to reach conclusions through these mental strategies, sometimes, our reasoning can be off. Read on to discover how our brain draws these conclusions and why they can be wrong.

## Heuristics

We make decisions and judgments every day – if we can trust someone, if we should do something (or not), which route to take, how to respond to someone who’s upset… the list goes on and on. If we carefully considered and analyzed every possible outcome of these decisions and judgments, we would never do anything else!

Thankfully, our mind makes things easier for us by using efficient thinking strategies known as heuristics. A heuristic is a mental shortcut that helps us make decisions and judgments quickly without having to spend a lot of time researching and analyzing information.

For example, when walking down the street, you see a piano tied to a rope above the sidewalk. Without a break in stride, you would likely choose to walk around that area instead of directly underneath the piano. Your intuition would tell you that walking under the piano could be dangerous, so you make a snap judgment to walk around the danger zone. You would probably not stop and assess the entire situation or calculate the probability of the piano falling on you or your chances of survival if that happened. You would use a heuristic to make the decision quickly and without using much mental effort.

Most of the time, heuristics are extremely helpful, but they can lead to errors in judgment. There are several different categories or types of heuristics. Let’s discuss three that, although useful in many situations, can lead even the most intelligent people to make dumb decisions: availability, representativeness, and base-rate heuristics.

## Availability Heuristic

First, the availability heuristic is a mental shortcut which helps us make a decision based on how easy it is to bring something to mind. In other words, we often rely on how easy it is to think of examples when making a decision or judgment.

For instance, in 2011, what percentage of crimes do you suppose involved violence? Most people are likely to guess a high percentage because of all the violent crimes – murder, rape, robbery, and assault – that are highlighted on the news. Yet the FBI reported that violent crimes made up less than 12% of all crimes in the United States in 2011.

The problem with the availability heuristic is that we assume that if several examples are readily available in our mind, the event or subject matter is commonplace. But, as with our example of violent crime, that assumption is not always correct.

However, there are many situations in which the availability heuristic is useful and accurate. For example, it’s part of what makes us careful in dangerous situations. If we can think of a similar situation that ended badly for someone else, we are more likely to be cautious and better protect ourselves.

## Representativeness Heuristic

Another type of heuristic is a representativeness heuristic, a mental shortcut which helps us make a decision by comparing information to our mental prototypes. For example, if someone was to describe an older woman as warm and caring with a great love of children, most of us would assume that the older woman is a grandmother. She fits our mental representation of a grandmother, so we automatically classify her into that category.

This heuristic, like others, saves us time and energy. We make a snap decision and assumption without thinking very much. Unfortunately, many examples of the representativeness heuristic involve succumbing to stereotypes. We might assume that someone who loves skateboarding is always getting into trouble or that a child dislikes healthy food.

## Base-Rate Heuristic

The final type of heuristic we’ll discuss in this lesson is the base-rate heuristic, a mental shortcut that helps us make a decision based on probability. For an example, imagine you live in a big city and hear an animal howling around midnight. You would probably assume it was just a dog, as wolves aren’t likely to be found in the city. Statistically, a wolf howling in the city would be very improbable.

Now, what do you think most people would do if presented with a situation in which they could either use the representativeness or base-rate heuristic? For example, Gail loves to play chess and listens to classical music. In her spare time, she enjoys shopping at used bookstores and touring museums. Now, is Gail more likely to be a nurse or a librarian? Which heuristic do you think most people would use to answer this question?

If you guessed the representativeness heuristic, you would be correct. Most would answer that Gail is probably a librarian. They used the representativeness heuristic, as she is representative of the mental image or prototype that we have of a librarian because she appears to be intelligent and loves to read.

In reality, though, it is far more likely that Gail is a nurse because there are far more nurses than librarians in the world. Yet, few people use the base-rate heuristic, partly because the representativeness information is so compelling.

## Lesson Summary

In summary, a heuristic is a mental shortcut that helps us make decisions and judgments quickly without having to spend a lot of time researching and analyzing information. Most of the time, heuristics are extremely helpful, but they can lead to errors in judgment.

The availability heuristic is a mental shortcut that helps us make a decision based on how easy it is to bring something to mind. We tend to assume that if several examples are readily available in our mind, the event or subject matter is commonplace.

The representativeness heuristic is a mental shortcut that helps us make a decision by comparing information to our mental prototypes. Unfortunately, many examples of the representativeness heuristic involve succumbing to stereotypes.

Finally, the base-rate heuristic is a mental shortcut that helps us make a decision based on probability. This is when we make a snap judgment based on our knowledge of how likely something is to occur or be true statistically.

## Key Terms

• Heuristic: a mental shortcut that helps us make judgements quickly
• Availability Heuristic: a mental shortcut that helps us make a decision based on how easy it is to remember something
• Representativeness Heuristic: a mental shortcut that helps us make decisions by comparing information to our mental prototypes
• Base-Rate Heuristic: a mental shortcut that helps us make decisions based on probability

## Learning Outcomes

Absorbing facts about heuristics via this lesson could prepare you to:

• Cite an example of a heuristic
• Specify and describe the three types of heuristics
• Discuss the benefits and drawbacks of each type