Heuristics

What are Heuristics?

As cognitive misers, we have a bag of tools that help us organize our perceptions effortlessly. These shortcuts—handy rules of the thumb that are part of our cognitive arsenal—are called heuristics.

Heuristics are quick and easy, but can result in biased information processing. Three of the most commonly used types of heuristics are:

• representativeness,
• availability,
• anchoring and adjustment.

Within the remainder of this literature we’ll discuss each at length.

The Representativeness Heuristic

The representativeness heuristic is the tendency to allocate a set of attributes to someone that match the prototype of a given category. It is a quick and easy way of putting people into categories. For instance, if you arrive at a hospital in need of help, you look for the person wearing a white coat and stethoscope, because these specific attributes indicate that the person is (representative of) a doctor.

It is important to note one drawback of using this mental shortcut. The decisions or judgments made on the basis of this rule tend to ignore the base rates—the frequency with which the given events or patterns occur in the total population. For example, consider an individual who has been described by a former neighbor as follows:

Do you think that Steve is a salesperson or a librarian?

Using the representativeness heuristic Opens in new window, people would most probably guess that Steve is a librarian, because he resembles their model of a librarian. In reality, this is not a very wise guess, as it ignores the base rates of the librarians and the salespersons in the sample.

Virtually, everyone knows that salespersons outnumber librarians. This fact makes it much more likely that Steve is in sales. But in estimating probabilities, people often ignore information on the base rates. The considerations of base rate frequency, however, do not affect the similarity of Steve to the stereotypes of librarians and salespersons. If people evaluate the probability by representativeness, base rates will be neglected.

The Availability Heuristic

Perhaps, the simplest kind of heuristic reasoning is availability Opens in new window. The availability heuristic is a method of estimating the likelihood of something, based on how easily it comes to mind. For instance, we might assess the divorce rate by thinking of its prevalence, amongst the people we know personally. Or when buying a car, we might estimate reliability from the comments made by the acquaintances and the colleagues. Because there will generally be a correspondence between what comes to mind easily and the likelihood of the underlying event, this heuristic can be useful.

The availability heuristic tends to bias our interpretations, because the ease with which we can imagine an event affects our estimate of how frequently that event occurs. The television and newspapers, for example, tend to cover only the most visible, violent events. People therefore tend to overestimate the incidents of violence and crime, as well as, the number of deaths from accidents and murder, because these events are most memorable.

As with all the cognitive shortcuts, a biased judgment occurs, because the sample of people and events that we remember is unlikely to be fair and full. The availability heuristic can contribute to the false consensus effect Opens in new window.

The Anchoring and Adjustment Heuristic

Anchoring and adjustment Opens in new window is a cognitive bias, that describes the common human tendency to rely too heavily, or ‘anchor’ on one trait or piece of information when making decisions. During the normal decision-making, individuals anchor or overly rely on specific information or a specific value, and then adjust to that value to account for the other elements of the circumstance. Usually, once the anchor is set, there is a bias towards that value.

Take for example, a person looking to buy a used car—they may focus excessively on the odometer reading, and the model year of the car, and use those criteria as a basis for evaluating the value of the car, rather than considering how well the engine or the transmission is maintained.