The representativeness heuristic

Heuristics are mental shortcuts or rules of thumb we use to make judgments and decisions quickly and efficiently. While they are often helpful, they can also lead to mistakes.

The representativeness heuristic is one such shortcut, and involves classifying something or someone based on how similar it is to a prototype, or typical instance, of a category.

How the Heuristic Works

When we use the representativeness heuristic, we compare new information to our existing mental schemas, or prototypes.

If the new information fits well with the characteristics of a particular prototype, we tend to assume it belongs in that category, even if this conclusion isn't statistically the most likely one.

For example, if we meet someone who is tanned, likes surfing, and has a laid-back attitude, we might quickly classify them as "Californian" (assuming that's our prototype for a Californian), even though statistically there are many more people in other regions who also fit the bill. with that description.

Ignorance of Base Rate Information

One of the main problems with using the representativeness heuristic is that it often leads us to ignore base rate information, which is information about the relative frequency of members of different categories in the population.

Imagine that a person named Brian is described to us as someone who is quiet, wears glasses, and enjoys reading poetry.

If we were asked whether Brian was more likely to be a classics professor or a truck driver, many people would say he is a classics professor because the description better fits the prototype of that profession.

However, this ignores the fact that there are many, many more truck drivers than classics professors in the general population.

Even if the description is more representative of a classics professor, the statistical probability might favor him being a truck driver.

Consequences of Using the Heuristic

While the representativeness heuristic can be useful for making quick judgments in situations where information is limited, it can also lead to errors and the formation of stereotypes.

By basing our judgments on how representative something is of a category, we may overlook more reliable or statistically relevant information.

Being aware of this tendency to classify based on similarity to prototypes, and remembering to consider base-rate information when available, can help mitigate the errors associated with this mental shortcut.