Cognitive bias is distortion in the way humans perceive reality (see also cognitive distortion). See also the lists of thinking-related topics. Some of these have been verified empirically in the field of psychology, others are considered general categories of bias. This article or section does not cite its references or sources. ... Reality in everyday usage means the state of things as they actually exist. ... Cognitive therapy and its variants traditionally identify ten cognitive distortions that maintain negative thinking and help to maintain negative emotions. ... Below is a list of lists of mental processes, methods of thinking (thinking skills), thinking styles, types of thought, and related topics which augment or exemplify these. ... A central concept in science and the scientific method is that all evidence must be empirical, or empirically based, that is, dependent on evidence or consequences that are observable by the senses. ... Psychology (from Greek: ψυχή, psukhē, spirit, soul; and λόγος, logos, knowledge) is an academic / applied discipline involving the scientific study of mental processes and behavior of humans and animals. ... This article does not cite any references or sources. ...

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, herd behaviour, and manias.
• Bias blind spot — the tendency not to compensate for one's own cognitive biases.
• Choice-supportive bias — the tendency to remember one's choices as better than they actually were.
• Confirmation bias — the tendency to search for or interpret information in a way that confirms one's preconceptions.
• Congruence bias — the tendency to test hypotheses exclusively through direct testing, in contrast to tests of possible alternative hypotheses.
• Contrast effect — the enhancement or diminishment of a weight or other measurement when compared with recently observed contrasting object.
• Déformation professionnelle — the tendency to look at things according to the conventions of one's own profession, forgetting any broader point of view.
• Endowment effect — "the fact that people often demand much more to give up an object than they would be willing to pay to acquire it".^[1]
• Focusing effect — prediction bias occurring when people place too much importance on one aspect of an event; causes error in accurately predicting the utility of a future outcome.
• Hyperbolic discounting — the tendency for people to have a stronger preference for more immediate payoffs relative to later payoffs, the closer to the present both payoffs are.
• Illusion of control — the tendency for human beings to believe they can control or at least influence outcomes that they clearly cannot.
• Impact bias — the tendency for people to overestimate the length or the intensity of the impact of future feeling states.
• Information bias — the tendency to seek information even when it cannot affect action.
• Irrational escalation — the tendency to make irrational decisions based upon rational decisions in the past or to justify actions already taken.
• Loss aversion — "the disutility of giving up an object is greater than the utility associated with acquiring it".^[2] (see also sunk cost effects and Endowment effect).
• Neglect of probability — the tendency to completely disregard probability when making a decision under uncertainty.
• Mere exposure effect — the tendency for people to express undue liking for things merely because they are familiar with them.
• Omission bias — The tendency to judge harmful actions as worse, or less moral, than equally harmful omissions (inactions).
• Outcome bias — the tendency to judge a decision by its eventual outcome instead of based on the quality of the decision at the time it was made.
• Planning fallacy — the tendency to underestimate task-completion times.
• Post-purchase rationalization — the tendency to persuade oneself through rational argument that a purchase was a good value.
• Pseudocertainty effect — the tendency to make risk-averse choices if the expected outcome is positive, but make risk-seeking choices to avoid negative outcomes.
• Reactance - the urge to do the opposite of what someone wants you to do out of a need to resist a perceived attempt to constrain your freedom of choice.
• Selective perception — the tendency for expectations to affect perception.
• Status quo bias — the tendency for people to like things to stay relatively the same (see also Loss aversion and Endowment effect).^[3]
• Unit bias — the tendency to want to finish a given unit of a task or an item with strong effects on the consumption of food in particular
• Von Restorff effect — the tendency for an item that "stands out like a sore thumb" to be more likely to be remembered than other items.
• Zero-risk bias — preference for reducing a small risk to zero over a greater reduction in a larger risk.

The bandwagon effect is the observation that people often do (or believe) things because many other people do (or believe) the same. ... Groupthink is a type of thought exhibited by group members who try to minimize conflict and reach consensus without critically testing, analyzing, and evaluating ideas. ... Herd behaviour is the term used to describe situations in which the individuals of any particular group react coherently. ... Mania is a severe medical condition characterized by extremely elevated mood, energy, and thought patterns. ... The bias blind spot is a cognitive bias about not compensating for ones own cognitive biases. ... A choice-supportive bias is an effect seen in memory when people are more likely to remember positive attributes as having been part of the option they chose than of the option they rejected. ... It has been suggested that Myside bias be merged into this article or section. ... Congruence bias is a type of cognitive bias similar to confirmation bias. ... A contrast effect is the enhancement or diminishment, relative to normal, of a perception and related performance as a result of immediately previous or simultaneous exposure to a stimulus of lesser or greater value in the same dimension. ... Déformation professionnelle is a French phrase, meaning a tendency to look at things from the point of view of ones own profession and forget a broader perspective. ... The endowment effect is a hypothesis that people value a good (object) more once their property right to it has been established. ... The focusing effect (or focusing illusion) is a cognitive bias that occurs when people place too much importance on one aspect of an event; this bias causes error in accurately predicting the utility of a future outcome. ... In behavioral economics, hyperbolic discounting refers to the empirical finding that people generally prefer smaller payoffs to larger payoffs when the smaller payoffs come sooner in time than the larger; when all the payoffs are either distant or proximal in time, people tend to prefer the larger. ... The illusion of control is the tendency for human beings to believe they can control or at least influence outcomes which they clearly cannot. ... The durability bias, later renamed impact bias, in affective forecasting refers to the tendency for people to overestimate the length of future feeling states. ... Information bias is a type of cognitive bias. ... Irrational escalation (sometimes referred to as Irrational escalation of commitment) is a term frequently used in psychology, philosophy, economics, and game theory to refer to a situation in which people can make irrational decisions based upon rational decisions in the past or to justify actions already taken. ... In prospect theory, loss aversion. ... It has been suggested that Bygones principle be merged into this article or section. ... The endowment effect is a hypothesis that people value a good (object) more once their property right to it has been established. ... The Neglect of Probability Bias, a type of cognitive bias, is the tendency to completely disregard probability when making a decision under uncertainty and is one simple way in which people regularly violate the normative rules for decision making. ... The mere exposure effect is a psychological artifact well known to advertisers: people express undue liking for things merely because they are familiar with them. ... The Omission Bias is a type of cognitive bias. ... The outcome bias is an error made in evaluating the quality of a decision when the outcome of that decision is already known. ... The planning fallacy refers to the tendency to underestimate task-completion times. ... It is a common phenomenon after people have invested a lot of time, money, or effort in something to convince themselves that it must have been worth it. ... The pseudocertainty effect is a concept from prospect theory. ... Reactance is an action in direct contradiction to rules and/or regulations that threaten or eliminate specific behavioral freedoms; it can occur when someone is heavily pressured to accept a certain view or attitude. ... Selective perception may refer to any number of cognitive biases in psychology related to the way expectations affect perception. ... Status quo bias is cognitive bias for the status quo; in other words, people like things to stay relatively the same. ... In prospect theory, loss aversion. ... The endowment effect is a hypothesis that people value a good (object) more once their property right to it has been established. ... The Von Restoff effect (named after Hedwig von Restorff), also called the isolation effect, predicts that an item that stands out like a sore thumb (called distinctive encoding) will be more likely to be remembered than other items. ... Zero-risk bias is a heuristic based on imperfect correlations. ...

Biases in probability and belief

Many of these biases are often studied for how they affect business and economic decisions and how they affect experimental research.

• Ambiguity effect — the avoidance of options for which missing information makes the probability seem "unknown".
• Anchoring — the tendency to rely too heavily, or "anchor," on one trait or piece of information when making decisions.
• Anthropic bias — the tendency for one's evidence to be biased by observation selection effects.
• Attentional bias — neglect of relevant data when making judgments of a correlation or association.
• Availability heuristic — a biased prediction, due to the tendency to focus on the most salient and emotionally-charged outcome.
• Clustering illusion — the tendency to see patterns where actually none exist.
• Conjunction fallacy — the tendency to assume that specific conditions are more probable than general ones.
• Gambler's fallacy — the tendency to assume that individual random events are influenced by previous random events. For example, "I've flipped heads with this coin so many times that tails is bound to come up sooner or later."
• Hindsight bias — sometimes called the "I-knew-it-all-along" effect, the inclination to see past events as being predictable.
• Illusory correlation — beliefs that inaccurately suppose a relationship between a certain type of action and an effect.
• Ludic fallacy — the analysis of chance related problems with the narrow frame of games. Ignoring the complexity of reality, and the non-gaussian distribution of many things.
• Neglect of prior base rates effect — the tendency to fail to incorporate prior known probabilities which are pertinent to the decision at hand.
• Observer-expectancy effect — when a researcher expects a given result and therefore unconsciously manipulates an experiment or misinterprets data in order to find it (see also subject-expectancy effect).
• Optimism bias — the systematic tendency to be over-optimistic about the outcome of planned actions.
• Overconfidence effect — the tendency to overestimate one's own abilities.
• Positive outcome bias — a tendency in prediction to overestimate the probability of good things happening to them (see also wishful thinking, optimism bias and valence effect).
• Primacy effect — the tendency to weigh initial events more than subsequent events.
• Recency effect — the tendency to weigh recent events more than earlier events (see also peak-end rule).
• Reminiscence bump — the effect that people tend to recall more personal events from adolescence and early adulthood than from other lifetime periods.
• Rosy retrospection — the tendency to rate past events more positively than they had actually rated them when the event occurred.
• Subadditivity effect — the tendency to judge probability of the whole to be less than the probabilities of the parts.
• Telescoping effect — the effect that recent events appear to have occurred more remotely and remote events appear to have occurred more recently.
• Texas sharpshooter fallacy — the fallacy of selecting or adjusting a hypothesis after the data are collected, making it impossible to test the hypothesis fairly.

The ambiguity effect is a cognitive bias where decision-making is affected due to a lack of information, or an “ambiguity. ... Anchoring or focalism is a term used in psychology to describe the common human tendency to rely too heavily, or anchor, on one trait or piece of information when making decisions. ... Anthropic bias is the bias arising when your evidence is biased by observation selection effects, according to philosopher Nick Bostrom. ... Attentional bias is a form of cognitive bias in which a person does not examine all possible outcomes when making a decision. ... The availability heuristic is a rule of thumb, heuristic, or cognitive bias, where people base their prediction of an outcome on the vividness and emotional impact rather than on actual probablity. ... The clustering illusion is the natural human tendency to see patterns where actually none exist. ... The conjunction fallacy is a logical fallacy that occurs when it is assumed that specific conditions are more probable than general ones. ... The gamblers fallacy is a logical fallacy which encompasses any of the following misconceptions: A random event is more likely to occur because it has not happened for a period of time; A random event is less likely to occur because it has not happened for a period of... Hindsight bias, sometimes called the I-knew-it-all-along effect, is the inclination to see events that have occurred as more predictable than they in fact were before they took place. ... Illusory correlations are beliefs that inaccurately suppose a relationship between a certain type of action and an effect. ... Ludic fallacy is a term coined by the philosopher of human knowledge Nassim Taleb. ... Generally, the word gaussian pertains to Carl Friedrich Gauss and his ideas. ... The effect of neglecting prior base rates is related to the representative heuristic. ... The observer-expectancy effect, in science, is a cognitive bias that occurs in science when a researcher expects a given result and therefore unconsciously manipulates an experiment or misinterprets data in order to find it. ... The Subject-expectancy effect, in science, is a cognitive bias that occurs in science when a subject expects a given result and therefore unconsciously manipulates an experiment or reports the expected result. ... Optimism bias is the demonstrated systematic tendency for people to be over-optimistic about the outcome of planned actions. ... Many people tend to be overconfident. ... The valence effect of prediction is the tendency for people to simply overestimate the likelihood of good things happening rather than bad things. ... Wishful thinking is the formation of beliefs and making decisions according to what might be pleasing to imagine instead of by appealing to evidence or rationality. ... Optimism bias is the demonstrated systematic tendency for people to be over-optimistic about the outcome of planned actions. ... The valence effect of prediction is the tendency for people to simply overestimate the likelihood of good things happening rather than bad things. ... The primacy effect, in psychology and sociology, is a cognitive bias that results from disproportionate salience of initial stimuli or observations. ... The recency effect, in psychology, is a cognitive bias that results from disproportionate salience of recent stimuli or observations. ... According to the peak-end rule, we judge our past experiences almost entirely on how they were at their peak (pleasant or unpleasant) and how they ended. ... The reminiscence bump is the effect in the temporal distribution of autobiographical memory revealed in research by David Rubin and others that people tend to recall more personal events from adolescence and early adulthood (10-25 years) than personal events from other lifetime periods. ... A kind of memory bias, rosy retrospection refers to the finding that subjects later rate past events more positively than they had actually rated them when the event occurred. ... The subadditivity effect is the tendency to judge probability of the whole to be less than the probabilities of the parts. ... In psychology and cognitive science, the telescoping effect is peoples tendency to perceive recent events as being more remote than they are, and to perceive distant events as being more recent than they are. ... The Texas sharpshooter fallacy is a logical fallacy where a cluster of statistically non-significant data is taken from its context, and therefore thought to have a common cause. ...

Social biases

Most of these biases are labeled as attributional biases. Attributional biases are cognitive biases which affect attribution -- the way we determine who or what was responsible for an event or action. ...

• Actor-observer bias — the tendency for explanations for other individual's behaviors to overemphasize the influence of their personality and underemphasize the influence of their situation. This is coupled with the opposite tendency for the self in that one's explanations for their own behaviors overemphasize their situation and underemphasize the influence of their personality. (see also fundamental attribution error).
• Egocentric bias — occurs when people claim more responsibility for themselves for the results of a joint action than an outside observer would.
• Forer effect (aka Barnum Effect) — the tendency to give high accuracy ratings to descriptions of their personality that supposedly are tailored specifically for them, but are in fact vague and general enough to apply to a wide range of people. For example, horoscopes.
• False consensus effect — the tendency for people to overestimate the degree to which others agree with them.
• Fundamental attribution error — the tendency for people to over-emphasize personality-based explanations for behaviors observed in others while under-emphasizing the role and power of situational influences on the same behavior (see also actor-observer bias, group attribution error, positivity effect, and negativity effect).
• Halo effect — the tendency for a person's positive or negative traits to "spill over" from one area of their personality to another in others' perceptions of them (see also physical attractiveness stereotype).
• Illusion of asymmetric insight — people perceive their knowledge of their peers to surpass their peers' knowledge of them.
• Illusion of transparency — people overestimate others' ability to know them, and they also overestimate their ability to know others.
• Ingroup bias — the tendency for people to give preferential treatment to others they perceive to be members of their own groups.
• Just-world phenomenon — the tendency for people to believe that the world is "just" and therefore people "get what they deserve."
• Lake Wobegon effect — the human tendency to report flattering beliefs about oneself and believe that one is above average (see also worse-than-average effect, and overconfidence effect).
• Notational bias — a form of cultural bias in which a notation induces the appearance of a nonexistent natural law.
• Outgroup homogeneity bias — individuals see members of their own group as being relatively more varied than members of other groups.
• Projection bias — the tendency to unconsciously assume that others share the same or similar thoughts, beliefs, values, or positions.
• Self-serving bias — the tendency to claim more responsibility for successes than failures. It may also manifest itself as a tendency for people to evaluate ambiguous information in a way beneficial to their interests (see also group-serving bias).
• Self-fulfilling prophecy — the tendency to engage in behaviors that elicit results which will (consciously or subconsciously) confirm our beliefs.
• System justification — the tendency to defend and bolster the status quo, i.e. existing social, economic, and political arrangements tend to be preferred, and alternatives disparaged sometimes even at the expense of individual and collective self-interest.
• Trait ascription bias — the tendency for people to view themselves as relatively variable in terms of personality, behavior and mood while viewing others as much more predictable.

In attribution theory, the fundamental attribution error (sometimes referred to as the actor-observer bias) is the tendency for people to over-emphasize dispositional, or personality-based, explanations for behaviors observed in others while under-emphasizing the role and power of situational influences on the same behavior. ... In attribution theory, the fundamental attribution error (also known as correspondence bias or overattribution effect and frequently confused with the actor-observer bias) is the tendency for people to over-emphasize dispositional, or personality-based, explanations for behaviors observed in others while under-emphasizing the role and power of situational... Egocentric bias occurs when people claim more responsibility for themselves for the results of a joint action than an outside observer would. ... Many skeptics believe the popularity of horoscopes (and astrology in general) is due to the Forer Effect. ... A horoscope calculated for January 1, 2000 at 12:01:00 A.M. Eastern Standard Time in New York City, New York, USA (Longitude: 074W0023 - Latitude: 40N4251). In astrology, a horoscope is a chart or diagram representing the positions of the Sun, Moon, and planets, the astrological aspects... The false consensus effect refers to the tendency for people to overestimate the degree to which others agree with them. ... In attribution theory, the fundamental attribution error (also known as correspondence bias or overattribution effect and frequently confused with the actor-observer bias) is the tendency for people to over-emphasize dispositional, or personality-based, explanations for behaviors observed in others while under-emphasizing the role and power of situational... In attribution theory, the fundamental attribution error (sometimes referred to as the actor-observer bias) is the tendency for people to over-emphasize dispositional, or personality-based, explanations for behaviors observed in others while under-emphasizing the role and power of situational influences on the same behavior. ... The group attribution error is a group-serving, attributional bias identical to the fundamental attribution error except that it occurs between members of different groups rather than different individuals. ... In psychology and cognitive science, the positivity effect is the tendency of people, when evaluating the causes of the behaviors of a person they like, to attribute positive behaviors to the persons inherent disposition and negative behaviors to situations surrounding the behaviors. ... The negativity effect is an attributional bias that occurs when subjects are asked what they think caused actions of other people whom they dislike. ... Halo effect refers to the cognitive bias in which in series of perceptions the interpretation of later ones are influenced by perception of former ones. ... The physical attractiveness stereotype is a term that psychologists use to refer to the tendency to assume that people who are physically attractive also possess other socially desirable personality traits. ... The illusion of asymmetric insight is a cognitive bias that involves the fact that people perceive their knowledge of others to surpass other peoples knowledge of them. ... The illusion of transparency is a tendency for people to overestimate the degree to which their personal mental state is known by others. ... Ingroup bias is the preferential treatment people give to whom they perceive to be members of their own groups. ... The just-world phenomenon, also called the just-world theory, just-world effect or just-world hypothesis, refers to the tendency for people to believe that the world is just and so therefore people get what they deserve. ... The Lake Wobegon effect is the human tendency to overestimate ones achievements and capabilities in relation to others. ... The worse-than-average effect or below-average effect is the opposite of the usually-pervasive Lake Wobegon effect (which may be called the better-than-average effect in contexts where the two are compared). ... Many people tend to be overconfident. ... Notational bias is a form of cultural bias in which a notation induces the appearance of a nonexistent natural law. ... Natural law or the law of nature (Latin lex naturalis) is a law whose content is set by nature, and that therefore has validity everywhere. ... According to the outgroup homogeneity bias, individuals see members of their own group as being relatively more varied than members of other groups. ... Psychological projection (or projection bias) can be defined as unconsciously assuming that others share the same or similar thoughts, beliefs, values, or positions on any given subject. ... A self-serving bias occurs when people are more likely to claim responsibility for successes than failures. ... Group-serving bias is identical to self-serving bias except that it takes place between groups rather than individuals, under which group members make dispositional attributions for their groups successes and situational attributions for group failures, and vice versa for outsider groups. ... This article or section needs copy editing for grammar, style, cohesion, tone and/or spelling. ... System justification refers to a social psychological tendency to defend and bolster the status quo, that is, to see it as good, fair, legitimate, and desirable. ... Trait ascription bias is the tendency for people to view themselves as relatively variable in terms of personality, behavior and mood while viewing others as much more predictable in their personal traits across different situations. ...

Memory errors

Further information: Memory bias

• False memory
• Hindsight bias, also known as the 'I-knew-it-all-along effect'.
• Selective Memory

Memory biases may either enhance or impair the recall of memory, or they may alter the content of what we report remembering. ... For the novel, see False Memory (novel) It has been suggested that Synthetic memory be merged into this article or section. ... Hindsight bias, sometimes called the I-knew-it-all-along effect, is the inclination to see events that have occurred as more predictable than they in fact were before they took place. ...

Common theoretical causes of some cognitive biases

• Attribution theory, especially:
  • Salience
• Cognitive dissonance, and related:
  • Impression management
  • Self-perception theory
• Heuristics, including:
  • Availability heuristic
  • Representativeness heuristic
• Adaptive Bias

Attribution theory is a social psychology theory developed by Fritz Heider, Harold Kelley, Edward E. Jones, and Lee Ross. ... Because too much data can cause “cognitive clutter”, individuals need a system to enable them to rank available data in terms of its immediate importance. ... Cognitive dissonance is a psychological term which describes the uncomfortable tension that comes from holding two conflicting thoughts at the same time, or from engaging in behavior that conflicts with ones beliefs. ... In sociology and social psychology, impression management is the process through which people try to control the impressions other people form of them. ... Self-perception theory is an account of attitude change developed by psychologist Daryl Bem. ... Look up Heuristic in Wiktionary, the free dictionary. ... The availability heuristic is a rule of thumb, heuristic, or cognitive bias, where people base their prediction of an outcome on the vividness and emotional impact rather than on actual probablity. ... The representativeness heuristic is a heuristic wherein we assume commonality between objects of similar appearance. ... Adaptive Bias is the idea that the human brain has evolved to reason adaptively, rather than truthfully or even rationally, and that Cognitive bias may have evolved as a mechanism to reduce the overall cost of cognitive errors as opposed to merely reducing the number of cognitive errors, when faced...

Notes

1. ^ (Kahneman, Knetsch, and Thaler 1991: 193) Richard Thaler coined the term "endowment effect."
2. ^ (Kahneman, Knetsch, and Thaler 1991: 193) Daniel Kahneman, together with Amos Tversky, coined the term "loss aversion."
3. ^ (Kahneman, Knetsch, and Thaler 1991: 193)

References

• Baron, J. (2000). Thinking and deciding (3d. edition). New York: Cambridge University Press. ISBN 0-521-65030-5
• Bishop, Michael A & Trout, J.D. (2004). Epistemology and the Psychology of Human Judgment. New York: Oxford University Press. ISBN 0-19-516229-3
• Gilovich, T. (1993). How We Know What Isn't So: The Fallibility of Human Reason in Everyday Life. New York: The Free Press. ISBN 0-02-911706-2
• Gilovich, T., Griffin D. & Kahneman, D. (Eds.). (2002). Heuristics and biases: The psychology of intuitive judgment. Cambridge, UK: Cambridge University Press. ISBN 0-521-79679-2
• Kahneman, D., Slovic, P. & Tversky, A. (Eds.). (1982). Judgment under Uncertainty: Heuristics and Biases. Cambridge, UK: Cambridge University Press. ISBN 0-521-28414-7
• Kahneman, Daniel, Jack L. Knetsch, and Richard H. Thaler. (1991). "Anomalies: The Endowment Effect, Loss Aversion, and Status Quo Bias." The Journal of Economic Perspectives 5(1):193-206.
• Plous, S. (1993). The Psychology of Judgment and Decision Making. New York: McGraw-Hill. ISBN 0-07-050477-6
• Tetlock, Philip E. (2005). Expert Politcal Judgment: how good is it? how can we know?. Princeton: Princeton University Press. ISBN 978-0-691-12302-8

See also

• Attribution theory
• Systematic bias
• Groupthink
• Logical fallacy
• Media bias
• Self-deception
• System justification