Bias List

Decision-Making Biases


Automation Bias

The propensity for humans to favor suggestions from automated decision making systems and to ignore contradictory information made without automation, even if it is correct.


Bandwagon Effect

The tendency to do (or believe) things because many other people do (or believe) the same.


Bias Blind Spot

The tendency to see oneself as less biased than other people, or to be able to identify more cognitive biases in others than in oneself.


Congruence Bias

The tendency to test hypotheses exclusively through direct testing, instead of testing possible alternative hypotheses.


Contrast Effect

The enhancement or reduction of a certain perception's stimuli when compared with a recently observed, contrasting object.


Decoy Effect

A phenomenon in marketing where consumers have a specific change in preference between two choices after being presented with a third choice.


Déformation Professionnelle

A tendency to look at things from the point of view of one's own profession rather than from a broader perspective.


Denomination Effect

The tendency to spend more money when it is denominated in small amounts (e.g. coins) rather than large amounts (e.g. bills).


Distinction Bias

The tendency to view two options as more dissimilar when evaluating them simultaneously than when evaluating them separately.


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.


Experimenter's Bias

The tendency for experimenters to believe, certify, and publish data that agree with their expectations for the outcome of an experiment, and to disbelieve, discard, or downgrade the corresponding weightings for data that appear to conflict with those expectations.


Extraordinarity Bias

The individual and social tendency to value an object more than others in the same category as a result of an extraordinarity property of that object that does not change the value in itself.


Focusing Effect

The tendency to place too much importance on one aspect of an event.



Drawing different conclusions from the same information, depending on how that information is presented.


Functional Fixedness

The inability to utilize an object for something other than what it was originally intended for.


Hyperbolic Discounting

The tendency for people to have a stronger preference for more immediate payoffs relative to later payoffs. Hyperbolic discounting leads to choices that are inconsistent over time – people make choices today that their future selves would prefer not to have made, despite using the same reasoning.


Illusion of Control

The tendency to overestimate one's degree of influence over other external events.


Impact Bias

The tendency 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.


Interloper Effect

The tendency to value third party consultation as objective, confirming, and without motive.


Irrational Escalation

The phenomenon where people justify increased investment in a decision, based on the cumulative prior investment, despite new evidence suggesting that the decision was probably wrong. Also known as the sunk cost fallacy.


Loss Aversion

Refers to people's tendency to strongly prefer avoiding losses to acquiring gains. This leads to risk aversion when people evaluate an outcome comprising similar gains and losses; since people prefer avoiding losses to making gains.


Money Illusion

The tendency to concentrate on the nominal value (face value) of money rather than its value in terms of purchasing power.


Neglect of Probability

The tendency to completely disregard probability when making a decision under uncertainty.


Normalcy Bias

The refusal to plan for, or react to, a disaster which has never happened before.


Not Invented Here

Aversion to contact with or use of products, research, standards, or knowledge developed outside a group.


Omission Bias

The tendency to judge harmful actions as worse, or less moral, than equally harmful omissions (inactions).


Planning Fallacy

The tendency to underestimate how much time it will take to complete a task.


Post-Purchase Rationalization

The tendency to persuade oneself through rational argument that a purchase was a good value.


Pseudocertaintity Effect

The tendency to make risk-averse choices if the expected outcome is positive, but make risk-seeking choices to avoid negative outcomes.



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.


Restraint Bias

The tendency to overestimate one's ability to show restraint in the face of temptation.


Risk Compensation

The tendency to take greater risks when perceived safety increases.


Scope Neglect

Occurs when the valuation of a problem is not valued with a multiplicative relationship to its size.


Selective Perception

The tendency for expectations to affect perception.


Semmelweis Reflex

The tendency to reject new evidence that contradicts a paradigm.


Status Quo Bias

The tendency to like things to stay relatively the same.


Time-Saving Bias

The tendency to misestimate the time that could be saved (or lost) when increasing (or decreasing) speed.


Zero-Risk Bias

The preference for reducing a small risk to zero over a greater reduction in a larger risk. This plays to the desire to have complete control over a single, more minor outcome, over the desire for more — but not complete — control over a greater, more unpredictable outcome.