Cognitive biases: List

Decision-making and behavioral biases Many of these biases are studied for how they affect belief formation and business decisions and scientific research. Bandwagon effect — the tendency to do (or believe) things because many other people do (or believe) the same. Related to groupthink, crowd psychology, herd behaviour, and manias. Bias blind spot — the […]

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Decision-making, belief, and behavioral biases: List

Many of these biases affect belief formation, business and economic decisions, and human behavior in general. They arise as a replicable result to a specific condition: when confronted with a specific situation, the deviation from what is normally expected can be characterized by: Name Description Ambiguity effect The tendency to avoid options for which missing […]

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Social Biases: List

Most of these biases are labeled as attributional biases. Name Description Actor–observer bias The tendency for explanations of other individuals’ behaviors to overemphasize the influence of their personality and underemphasize the influence of their situation (see also Fundamental attribution error), and for explanations of one’s own behaviors to do the opposite (that is, to overemphasize […]

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Memory Biases: List

In psychology and cognitive science, a memory bias is a cognitive bias that either enhances or impairs the recall of a memory (either the chances that the memory will be recalled at all, or the amount of time it takes for it to be recalled, or both), or that alters the content of a reported […]

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The Current Moment Bias

Humans have a really hard time imagining ourselves in the future and altering our behaviors and expectations accordingly. Most of us would rather experience pleasure in the current moment, while leaving the pain for later. This is a bias that is of particular concern to economists (i.e. our unwillingness to not overspend and save money) […]

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Status-Quo Bias

Humans tend to be apprehensive of change, which often leads us to make choices that guarantee that things remain the same, or change as little as possible. Needless to say, this has ramifications in everything from politics to economics. We like to stick to our routines, political parties, and our favorite meals at restaurants. Part […]

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Observational Selection Bias

This is that effect of suddenly noticing things we didn’t notice that much before — but we wrongly assume that the frequency has increased. A perfect example is what happens after we buy a new car and we inexplicably start to see the same car virtually everywhere. A similar effect happens to pregnant women who […]

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Neglecting Probability

Very few of us have a problem getting into a car and going for a drive, but many of us experience great trepidation about stepping inside an airplane and flying at 35,000 feet. Flying, quite obviously, is a wholly unnatural and seemingly hazardous activity. Yet virtually all of us know and acknowledge the fact that […]

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Ingroup Bias

Somewhat similar to the confirmation bias is the ingroup bias, a manifestation of our innate tribalistic tendencies. And strangely, much of this effect may have to do with oxytocin — the so-called “love molecule.” This neurotransmitter, while helping us to forge tighter bonds with people in our ingroup, performs the exact opposite function for those […]

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Reactance

Reactance is a motivational reaction to offers, persons, rules, or regulations that threaten or eliminate specific behavioral freedoms. Reactance occurs when a person feels that someone or something is taking away his or her choices or limiting the range of alternatives. Reactance can occur when someone is heavily pressured to accept a certain view or attitude. Reactance can cause […]

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Reactive devaluation

Reactive devaluation is a cognitive bias that occurs when a proposal is devalued if it appears to originate from an antagonist. The bias was proposed by Lee Ross and Constance Stillinger. In an initial experiment conducted in 1991, Stillinger and co-authors asked pedestrians whether they would support a drastic bilateral nuclear arms reduction program. If they were told the proposal came from […]

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Recency illusion

The recency illusion is the belief or impression that a word or language usage is of recent origin when it is in fact long-established. The term was invented by Arnold Zwicky, a linguist at Stanford University who was primarily interested in examples involving words, meanings, phrases, and grammatical constructions. However, use of the term is not restricted to linguistic phenomena: Zwicky […]

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Restraint bias

Restraint bias is the tendency for people to overestimate their ability to control impulsive behavior. An inflated self-control belief may lead to greater exposure to temptation, and increased impulsiveness. Therefore, the restraint bias has bearing on addiction. For example, someone might experiment with drugs, simply because they believe they can resist any potential addiction. An individual’s inability to control, […]

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Rhyme-as-reason effect

The rhyme-as-reason effect (or Eaton-Rosen phenomenon) is a cognitive bias whereupon a saying or aphorism is judged as more accurate or truthful when it is rewritten to rhyme. In experiments, subjects judged variations of sayings which did and did not rhyme, and tended to evaluate those that rhymed as more truthful (controlled for meaning). For example, the statement “What sobriety conceals, alcohol reveals” […]

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Risk compensation

Risk compensation is a theory which suggests that people typically adjust their behavior in response to the perceived level of risk, becoming more careful where they sense greater risk and less careful if they feel more protected. Although usually small in comparison to the fundamental benefits of safety interventions, it may result in a lower net benefit than expected. By […]

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Selective perception

Selective perception is the tendency to not notice and more quickly forget stimuli that causes emotional discomfort and contradicts our prior beliefs. For example, a teacher may have a favorite student because they are biased by in-group favoritism. The teacher ignores the student’s poor attainment. Conversely, they might not notice the progress of their least favorite student. […]

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Semmelweis reflex

The Semmelweis reflex or “Semmelweis effect” is a metaphor for the reflex-like tendency to reject new evidence or new knowledge because it contradicts established norms, beliefs or paradigms. The term originated from the story of Ignaz Semmelweis, who discovered that childbed fever mortality rates reduced ten-fold when doctors washed their hands with a chlorine solution between patients. His hand-washing suggestions were rejected […]

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Subjective validation

Subjective validation, sometimes called personal validation effect, is a cognitive bias by which a person will consider a statement or another piece of information to be correct if it has any personal meaning or significance to them. In other words, a person whose opinion is affected by subjective validation will perceive two unrelated events (i.e., a coincidence) to be related […]

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Subadditivity effect

The subadditivity effect is the tendency to judge probability of the whole to be less than the probabilities of the parts. Example For instance, subjects in one experiment judged the probability of death from cancer in the United States was 18%, the probability from heart attack was 22%, and the probability of death from “other natural causes” was […]

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Framing effect

Framing effect is an example of cognitive bias, in which people react differently to a particular choice depending on whether it is presented as a loss or as a gain. People tend to avoid risk when a positive frame is presented but seek risks when a negative frame is presented. Gain and loss are defined in the scenario as […]

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Hard–easy effect

The hard–easy effect is a cognitive bias that occurs when, based on a specific level of difficulty of a given task, subjective judgements do not accurately reflect the true difficulty of that task. This manifests as a tendency to overestimate the probability of success in difficult tasks, and to underestimate the probability of success in easy tasks.

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Hostile media effect

The hostile media effect, originally deemed the hostile media phenomenon and sometimes called hostile media perception, is a perceptual theory of mass communication that refers to the finding that people with strong biases toward an issue (partisans) perceive media coverage as biased against their opinions, regardless of the reality. Proponents of the hostile media effect argue that this finding cannot be attributed to the presence […]

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Identifiable victim effect

Identifiable victim effect” refers to the tendency of individuals to offer greater aid when a specific, identifiable person (“victim”) is observed under hardship, as compared to a large, vaguely defined group with the same need. The effect is also observed when subjects administer punishment rather than reward. Participants in a study were more likely to mete out […]

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IKEA effect

The IKEA effect is a cognitive bias that occurs when consumers place a disproportionally high value on products they partially created. The name derives from the Swedish manufacturer and furniture retailer IKEA, which sells many furniture products that require assembly. Official experiment results on the IKEA effect were first published by Michael I. Norton of Harvard Business School, Daniel Mochon of Yale University, and Dan Ariely of Duke […]

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Illusion of control

The illusion of control is the tendency for people to overestimate their ability to control events, for instance to feel that they control outcomes that they demonstrably have no influence over. The effect was named by psychologist Ellen Langer and has been replicated in many different contexts. It is thought to influence gambling behavior and belief in the paranormal. Along with illusory superiority and optimism bias, the illusion […]

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Illusory correlation

Illusory correlation is the phenomenon of perceiving a relationship between variables (typically people, events, or behaviors) even when no such relationship exists. A common example of this phenomenon would be when people form false associations between membership in a statistical minority group and rare (typically negative) behaviors as variables that are novel or salient tend to capture the attention. This is one […]

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Impact bias

The impact bias, a form of which is the durability bias, in affective forecasting, is the tendency for people to overestimate the length or the intensity of future feeling states. Causes Other explanations for the occurrence of the impact bias are the following: Misconstrual of future events When predicting how an experience will impact us emotionally, events which have […]

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Information bias

Information bias is a type of cognitive bias, and involves e.g. distorted evaluation of information. An example of information bias is believing that the more information that can be acquired to make a decision, the better, even if that extra information is irrelevant for the decision.

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Insensitivity to sample size

Insensitivity to sample size is a cognitive bias that occurs when people judge the probability of obtaining a sample statistic without respect to the sample size. For example, in one study subjects assigned the same probability to the likelihood of obtaining a mean height of above six feet [183 cm] in samples of 10, 100, and 1,000 men. In other words, variation […]

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Escalation of commitment

Escalation of commitment was first described by Barry M. Staw in his 1976 paper, “Knee deep in the big muddy: A study of escalating commitment to a chosen course of action”. More recently the term sunk cost fallacy has been used to describe the phenomenon where people justify increased investment in a decision, based on the cumulative prior investment, despite new […]

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Less-is-better effect

The less-is-better effect is a type of preference reversal that occurs when the lesser or smaller alternative of a proposition is preferred when evaluated separately, but not evaluated together. The term was first proposed by Christopher Hsee. The effect has also been studied by Dan Ariely.

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Money illusion

In economics, money illusion, or price illusion, refers to the tendency of people to think of currency in nominal, rather than real, terms. In other words, the numerical/face value (nominal value) of money is mistaken for its purchasing power (real value). This is false, as modern fiat currencies have no intrinsic value and their real value is derived from their ability to be […]

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Negativity effect

In psychology, the negativity effect is the tendency of people, when evaluating the causes of the behaviors of a person they dislike, to attribute their positive behaviors to the environment and their negative behaviors to the person’s inherent nature. The negativity effect is the inverse of the positivity effect, which is found when people evaluate the causes of the behaviors of a person […]

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Selection bias

Selection bias is a statistical bias in which there is an error in choosing the individuals or groups to take part in a scientific study. It is sometimes referred to as the selection effect. The phrase “selection bias” most often refers to the distortion of a statisticalanalysis, resulting from the method of collecting samples. If the selection bias is not taken into account, […]

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Omission bias

The omission bias is an alleged type of cognitive bias. It is the tendency to judge harmful actions as worse, or less moral than equally harmful omissions (inactions) due to the fact that actions are more obvious than inactions. It is contentious as to whether this represents a systematic error in thinking, or is supported by a substantive moral […]

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Optimism bias

The optimism bias (also known as unrealistic or comparative optimism) is a bias that causes a person to believe that they are less at risk of experiencing a negative event compared to others. There are four factors that cause a person to be optimistically biased: their desired end state, their cognitive mechanisms, the information they have about themselves versus others, and overall […]

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Ostrich effect

In behavioral finance, the ostrich effect is the avoidance of apparently risky financial situations by pretending they do not exist. The name comes from the common (but false) legend that ostriches bury their heads in the sand to avoid danger. Galai and Sade (2006) explain differences in returns in the fixed income market by using a psychological explanation, which they name the “ostrich […]

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Outcome bias

The outcome bias is an error made in evaluating the quality of a decision when the outcome of that decision is already known. Specifically, the outcome effect occurs when the same “behavior produce[s] more ethical condemnation when it happen[s] to produce bad rather than good outcome, even if the outcome is determined by chance.” While similar to […]

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Pareidolia

Pareidolia  is a psychological phenomenon involving a vague and random stimulus (often an image or sound) being perceived as significant, a form of apophenia. Common examples include seeing images of animals or faces in clouds, the man in the moon or the Moon rabbit, and hearing hidden messages on records when played in reverse. The word comes from the Greek words para (παρά, “beside, alongside, instead”) in this context meaning something […]

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Conservatism

In cognitive psychology and decision science, conservatism or conservatism bias is a bias in human information processing. This bias describes human belief revision in which persons over-weigh the prior distribution (base rate) and under-weigh new sample evidence when compared to Bayesian belief-revision. According to the theory, “opinion change is very orderly, and usually proportional to the numbers of Bayes’ Theorem – but it is insufficient in amount”. In other words, persons update their […]

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Decoy effect

In marketing, the decoy effect (or asymmetric dominance effect) is the phenomenon whereby consumers will tend to have a specific change in preference between two options when also presented with a third option that isasymmetrically dominated. An option is asymmetrically dominated when it is inferior in all respects to one option; but, in comparison to the other option, it […]

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Pseudocertainty effect

In prospect theory, the pseudocertainty effect is people’s tendency to perceive an outcome as certain while in fact it is uncertain.[1] It is observed in multi-stage decisions, in which evaluation of outcomes in previous decision stage is discarded when making an option in subsequent stages. Example Kahneman and Tversky (1986) illustrated the pseudocertainty effect by the following examples. First, […]

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Pro-innovation bias

In diffusion of innovation theory, a pro-innovation bias is the belief that an innovation should be adopted by whole society without the need of its alteration. The innovation’s “champion” has such strong bias in favor of the innovation, that he/she may not see its limitations or weaknesses and continues to promote it nonetheless.

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Pessimism bias

Pessimism bias is an effect in which people exaggerate the likelihood that negative things will happen to them. It contrasts with optimism bias. The difference is that we are in an improbable way worried about our society’s future.Conversely, optimism bias is a tendency to underestimate personal risks and overestimate the likelihood of positive life events. Depressed people are particularly likely […]

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Availability cascade

Availability cascade, also known as The truth effect, the illusory truth effect or the illusion-of-truth effect is the tendency to believe information to be correct because we are exposed to it more times. Explanation The effect was first named and defined following the results in a study from 1977. Participants in it were given a list of 60 factoids which were plausible, but […]

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Observer-expectancy effect

The observer-expectancy effect (also called the experimenter-expectancy effect, expectancy bias, observer effect, or experimenter effect) is a form of reactivity in which a researcher’s cognitive bias causes them to unconsciously influence the participants of an experiment. Confirmation bias can lead to the experimenter interpreting results incorrectly because of the tendency to look for information that […]

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Acquiescence bias

Acquiescence bias is a category of response bias in which respondents to a survey have a tendency to agree with all the questions or to indicate a positive connotation. Acquiescence is sometimes referred to as “yea-saying” and is the tendency of a respondent to agree with a statement when in doubt. This particularly is in the […]

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Halo effect

The halo effect is a cognitive bias in which an observer’s overall impression of a person influences the observer’s feelings and thoughts about that person’s character. It was named by psychologist Edward Thorndike in reference to a person being perceived as having a halo.

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Self-selection bias

In statistics, self-selection bias arises in any situation in which individuals select themselves into a group, causing a biased sample with non-probability sampling. It is commonly used to describe situations where the characteristics of the people which cause them to select themselves in the group create abnormal or undesirable conditions in the group. Self-selection bias is a […]

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Systemic bias

Systemic bias is the inherent tendency of a process to support particular outcomes. The term is a neologism that generally refers to human systems such as institutions; the equivalent bias in non-human systems (such as measurement instruments or mathematical models used to estimate physical quantities) is often called systematic bias, and leads to systematic error […]

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