What Is Cognitive Bias? | Definition, Types & Examples

Cognitive bias is the tendency to act in an irrational way due to our limited ability to process information objectively. It is not always negative, but it can cloud our judgment and affect how clearly we perceive situations, people, or potential risks.

Example: Cognitive bias
One common manifestation of cognitive bias is the stereotype that women are less competent or less committed to their jobs. These stereotypes may linger in managers’ subconscious, influencing their hiring and promoting decisions. This, in turn, can lead to workplace discrimination.

Everyone is susceptible to cognitive bias, and researchers are no exception to that. Therefore, cognitive bias can be a source of research bias.

What is cognitive bias?

Cognitive bias is an umbrella term used to describe our systematic but flawed patterns of responses to judgment- and decision-related problems. These patterns are predictably nonrandom. While based on our beliefs and experiences, they often go against logic or probability.

Although we like to think of ourselves as rational beings who process all information before making a decision, this is often not the case. Everyone is prone to cognitive bias to a different degree.

Cognitive biases are hardwired into our brains and can help us navigate the information overload inherent to everyday life. If we had to think carefully before all of our actions, it would be really hard to function.

To be more efficient, our brains rely on our experiences and beliefs more than we realize. These become mental shortcuts (also called heuristics). These rules of thumb help us make judgments and predictions. Because this process is intuitive or subconscious, people often don’t realize they are acting based on biases or preconceived notions.

What causes cognitive bias?

Our tendency towards cognitive bias can come from many different sources. A few of these include:

  • Limited information-processing capacity. Because our minds have a limited ability to store and recall information, we simply can’t consider all the relevant information when we make an inference or decision. Usually, we are forced to focus on a subset of the available information.
  • Emotions. If our decision involves our loved ones, as opposed to total strangers, we will evaluate the situation differently.
  • Motivation. Our judgments are influenced by our existing attitudes and beliefs. We are very likely to choose the beliefs and strategies that are most likely to help us arrive at the conclusions we want to arrive at.
  • Social influence. People have a tendency to conform to the opinions expressed earlier by others or to act in socially desirable ways. This can influence collective behaviors, such as voting.
  • Heuristics, or mental shortcuts. Our minds use simple rules to arrive at a conclusion in a “fast-and-frugal” way. The aim is not to capture the problem in all its complexity, or even to arrive at the optimal solution, but to arrive at a “good enough” solution quickly while minimizing mental effort.
  • Age. There is evidence suggesting that older people show less cognitive flexibility. This implies that as we get older, we are more likely to exhibit cognitive bias.

Impact of cognitive bias

Relying on mental shortcuts in our everyday life is effective and leads to faster decision-making when timing is more important than accuracy. However, cognitive bias can lead us to misunderstand events, facts, or other people. This, in turn, can affect our behavior in a wide range of situations.

Cognitive biases can negatively impact:

  • Our decision-making ability, limiting how receptive we are to new or contradictory information.
  • How accurately we can recall incidents—for example, an event where we were an eyewitness. Inaccurate or incomplete recollection of events can lead to recall bias.
  • Our anxiety levels, making us focus only on negative events or aspects of our lives.
  • Our relationships with others, when we are too quick to judge their personality on the basis of a single trait.
  • Our critical thinking, leading us to perpetuate misconceptions or misinformation that can be harmful to others.

What are different types of cognitive bias?

Although there is no exhaustive list of all types of cognitive bias, below are some common ones that often distort our thinking.

  • Anchoring bias is the tendency to rely on the first piece of information offered. It applies particularly to numbers. Negotiators use anchoring bias by starting with a number that is too low or too high. They know that this number will set the bar for subsequent offers.
  • The framing effect occurs when people make a choice based on whether the options presented to them are phrased in a positive or a negative way, for example in terms of loss or gain, reward or punishment.
  • Actor–observer bias is the tendency to attribute our actions to external factors and other people’s actions to internal ones. For example, if you and a classmate both fail an exam, you may think that your failure was due to the difficulty of the questions, while your classmate’s was due to poor preparation.
  • The availability heuristic (or availability bias) applies when we place greater value on information that is available to us or comes to mind quickly. Because of this, we tend to overestimate the probability of similar things happening again.
  • Confirmation bias refers to our tendency to look for evidence confirming what we already believe, viewing facts and ideas we encounter as further confirmation. Confirmation bias also leads us to ignore any evidence that seems to support an opposing view.
  • The halo effect refers to how our perception of a single trait can influence how we perceive other aspects, particularly in regards to someone’s personality. For example, when we consider someone to be physically attractive, it often determines how we rate their other qualities.
  • The Baader–Meinhof phenomenon (or frequency illusion) is the tendency to see new information, names, or patterns “everywhere” soon after they’re first brought to our attention.
  • The belief bias describes the tendency to judge an argument based on how plausible we find the conclusion to be, rather than how much evidence is provided to support this conclusions over the course of the argument.
  • The affect heuristic occurs when our current emotional state or mood influences our decisions. Instead of evaluating the situation objectively, we rely on our “gut feelings” and respond according to how we feel.
  • The representativeness heuristic occurs when we estimate the probability of an event based on how similar it is to a known situation. In other words, we compare it to a situation, prototype, or stereotype we already have in mind.

Cognitive bias examples

Because cognitive bias often causes us to perceive the world around us in an oversimplified way, it can have far-reaching consequences.

Example: Cognitive bias in decision-making 
Anchoring bias is a type of cognitive bias often used in sales. For example, Apple first introduced the iPhone at a price of $600 and then quickly discounted it to $400. This, of course, was deliberate. By imprinting the price of $600 in people’s minds, Apple was able to make consumers think that $400 was a real bargain.

The traditional approach to price setting would be to ask focus groups about various price tags for the phone and, based on participants’ feedback, pick the price they thought would be most profitable ($400).

But the phone was innovative; consumers had never seen such a product before. If Apple had set the initial price at $400, consumers wouldn’t be in a position to decide whether the phone was worth its price tag, as they would have had no basis for comparison.

In a medical context, cognitive bias can lead even seasoned doctors to wrong diagnoses.

Example: Cognitive bias in medicine
A common mistake in medical diagnosis is the so-called bandwagon effect. This is the tendency to adopt certain behaviors or opinions simply because others are doing so.

For example, the nurses in an emergency department ask the doctor to see and quickly discharge a patient. They explain that she is a “regular” in the department and is seeking drugs. However, labels like this can stick to a patient and lead to misdiagnosis. When the patient visits again with abdominal pain, the doctor, who is very busy, performs a quick physical exam and prescribes painkillers.

Due to the bandwagon effect (“if everyone thinks so, it must be right”), the doctor doesn’t take the necessary steps to arrive at a diagnosis independent of the labels applied by others, and she misses that the patient had appendicitis.

In everyday life, we are often tricked by cognitive bias and over- or underestimate how risky our choices might be.

Example: Cognitive bias in real life 
Many people think that traveling by plane is more dangerous than traveling by car. This, in part, is due to the availability heuristic (availability bias).

Dramatic images of plane crashes are often in the news and therefore more vivid and readily available in our minds than similar images of car crashes. This can make us believe that plane crashes are more frequent than they actually are.

Other types of research bias

Frequently asked questions

What is the bandwagon effect?

The bandwagon effect is a type of cognitive bias. It describes the tendency of people to adopt behaviors or opinions simply because others are doing so, regardless of their own beliefs.

What is attention bias?

Attention bias is a common cognitive bias that means we are ignoring important information. Because our attention is limited, we tend to direct our awareness to specific things in our environment, while filtering out others.

Although this mechanism generally makes us more efficient, it can cause us to filter out information or signals in the environment that we shouldn’t be ignoring, leading to research bias.

What are signs of cognitive bias?

Although it’s harder to identity cognitive bias in our own thinking than in that of others, here are a few examples of “red flags” to bear in mind:

  • Selecting information that is in line with our existing beliefs
  • Focusing too much on initial information and failing to adjust our judgment when new information becomes available
  • Making overgeneralizations or jumping to conclusions when the evidence is scarce
  • Blaming external factors for our failures, while taking all the credit for our successes
What is myside bias?

Myside bias is a type of cognitive bias where individuals process information in a way that favors their prior beliefs and attitudes. It occurs when people search for, interpret, and recall information that confirms their opinions, and refute opinions different from their own—such as selecting news sources that agree with one’s political affiliation, while ignoring any opposing arguments from other sources.

Myside bias is closely related to confirmation bias. Although some researchers use the terms interchangeably, others use myside bias to refer to the tendency of processing information that supports one’s own position.

Sources in this article

We strongly encourage students to use sources in their work. You can cite our article (APA Style) or take a deep dive into the articles below.

This Scribbr article

Nikolopoulou, K. (2023, December 11). What Is Cognitive Bias? | Definition, Types & Examples. Scribbr. Retrieved June 18, 2024, from https://www.scribbr.com/research-bias/cognitive-bias/


Blanco, F. (2017). Cognitive Bias. In: Vonk, J., Shackelford, T. (eds) Encyclopedia of Animal Cognition and Behavior. Springer, Cham. https://doi.org/10.1007/978-3-319-47829-6_1244-1

Wilson, C. G., Nusbaum, A. T., Whitney, P., & Hinson, J. M. (2017). Age-differences in cognitive flexibility when overcoming a preexisting bias through feedback. Journal of Clinical and Experimental Neuropsychology, 40(6), 586–594. https://doi.org/10.1080/13803395.2017.1398311

The Canadian Medical Protective Association. (2012, April 26). CMPA Good Practices Guide : common cognitive biases. CMPA. https://www.cmpa-acpm.ca/serve/docs/ela/goodpracticesguide/pages/human_factors/Cognitive_biases/pdf/hf_common_cognitive_biases-e.pdf

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Kassiani Nikolopoulou

Kassiani has an academic background in Communication, Bioeconomy and Circular Economy. As a former journalist she enjoys turning complex scientific information into easily accessible articles to help students. She specializes in writing about research methods and research bias.