Heuristics: The Psychology of Mental Shortcuts


Heuristics (also called “mental shortcuts” or “rules of thumb") are efficient mental processes that help humans solve problems and learn new concepts. These processes make problems less complex by ignoring some of the information that’s coming into the brain, either consciously or unconsciously. Today, heuristics have become an influential concept in the areas of judgment and decision-making.

History and Origins

Gestalt psychologists postulated that humans solve problems and perceive objects based on heuristics.

In the early 20th century, the psychologist Max Wertheimer identified laws by which humans group objects together into patterns (e.g. a cluster of dots in the shape of a rectangle).

The heuristics most commonly studied today are those that deal with decision-making. In the 1950s, economist and political scientist Herbert Simon published his A Behavioral Model of Rational Choice, which focused on the concept of on bounded rationality: the idea that people must make decisions with limited time, mental resources, and information.

In 1974, psychologists Amos Tversky and Daniel Kahneman pinpointed specific mental processes used to simplify decision-making. They showed that humans rely on a limited set of heuristics when making decisions with information about which they are uncertain—for example, when deciding whether to exchange money for a trip overseas now or a week from today. Tversky and Kahneman also showed that, although heuristics are useful, they can lead to errors in thinking that are both predictable and unpredictable.

In the 1990s, research on heuristics, as exemplified by the work of Gerd Gigerenzer’s research group, focused on how factors in the environment impact thinking–particularly, that the strategies the mind uses are influenced by the environment–rather than the idea that the mind uses mental shortcuts to save time and effort.

Significant Psychological Heuristics

Tversky and Kahneman’s 1974 work, Judgment under Uncertainty: Heuristics and Biases, introduced three key characteristics: representativeness, anchoring and adjustment, and availability. 

The representativeness heuristic allows people to judge the likelihood that an object belongs in a general category or class based on how similar the object is to members of that category.

To explain the representativeness heuristic, Tversky and Kahneman provided the example of an individual named Steve, who is “very shy and withdrawn, invariably helpful, but with little interest in people or reality. A meek and tidy soul, he has a need for order and structure, and a passion for detail.” What is the probability that Steve works in a specific occupation (e.g. librarian or doctor)? The researchers concluded that, when asked to judge this probability, individuals would make their judgment based on how similar Steve seemed to the stereotype of the given occupation.

The anchoring and adjustment heuristic allows people to estimate a number by starting at an initial value (the “anchor”) and adjusting that value up or down. However, different initial values lead to different estimates, which are in turn influenced by the initial value.

To demonstrate the anchoring and adjustment heuristic, Tversky and Kahneman asked participants to estimate the percentage of African countries in the UN. They found that, if participants were given an initial estimate as part of the question (for example, is the real percentage higher or lower than 65%?), their answers were rather close to the initial value, thus seeming to be "anchored" to the first value they heard.

The availability heuristic allows people to assess how often an event occurs or how likely it will occur, based on how easily that event can be brought to mind. For example, someone might estimate the percentage of middle-aged people at risk of a heart attack by thinking of the people they know who have had heart attacks.

Tversky and Kahneman's findings led to the development of the heuristics and biases research program.

Subsequent works by researchers have introduced a number of other heuristics.

The Usefulness of Heuristics

There are several theories for the usefulness of heuristics. The accuracy-effort trade-off theory states that humans and animals use heuristics because processing every piece of information that comes into the brain takes time and effort. With heuristics, the brain can make faster and more efficient decisions, albeit at the cost of accuracy. 

Some suggest that this theory works because not every decision is worth spending the time necessary to reach the best possible conclusion, and thus people use mental shortcuts to save time and energy. Another interpretation of this theory is that the brain simply does not have the capacity to process everything, and so we must use mental shortcuts.

Another explanation for the usefulness of heuristics is the ecological rationality theory. This theory states that some heuristics are best used in specific environments, such as uncertainty and redundancy. Thus, heuristics are particularly relevant and useful in specific situations, rather than at all times.

Key Takeaways

  • Heuristics are efficient mental processes (or "mental shortcuts") that help humans solve problems or learn a new concept.
  • In the 1970s, researchers Amos Tversky and Daniel Kahneman identified three key heuristics: representativeness, anchoring and adjustment, and availability.
  • The work of Tversky and Kahneman led to the development of the heuristics and biases research program.