256 cognitive biases
Complete encyclopedia of cognitive biases and heuristics that affect your decisions.
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Showing: 256 biases
Confirmation bias
The tendency to search for, interpret, and remember information in a way that confirms our preexisting beliefs.
Anchoring effect
Over-reliance on the first piece of information encountered (the "anchor") when making decisions.
Sunk cost fallacy
Continuing an action because of already incurred costs, rather than evaluating future benefits.
Availability heuristic
Judging the likelihood of events based on how easily examples come to mind.
Loss aversion
Losses are psychologically about twice as powerful as equivalent gains.
Framing effect
Making different decisions depending on how the same information is presented.
Hindsight bias
The belief, after an event, that it was predictable ("I knew it all along").
Authority bias
Attributing greater credibility to opinions of people perceived as authorities.
Social proof
Following the actions of others in uncertain situations.
Halo effect
One positive trait influences the assessment of the entire person or product.
Optimism bias
The belief that we are less likely to experience negative events than others.
Dunning-Kruger effect
People with low competence overestimate their abilities, while experts underestimate theirs.
Bandwagon effect
Adopting beliefs or behaviors because many others do so.
Status quo bias
Preference for the current state of affairs, resistance to change.
Recency bias
Giving more weight to recent events than earlier ones.
Overconfidence bias
Overestimating one's own knowledge, skills, or prediction accuracy.
Endowment effect
Assigning greater value to things we own than to identical things we don't have.
Groupthink
The desire for harmony in a group leads to overlooking critical evaluation and alternative views.
Gambler's fallacy
The belief that past random events affect the probability of future ones.
Spotlight effect
Overestimating how much others pay attention to us.
Representativeness heuristic
Judging probability based on similarity to a typical case.
Base rate neglect
Ignoring general statistics in favor of specific information.
Conjunction fallacy
Assuming a detailed scenario is more likely than a general one.
Hot hand fallacy
The belief that a series of successes increases the chances of another success.
Neglect of probability
Ignoring probability when assessing risk, focusing on possibility of occurrence.
Zero-risk bias
Preferring complete elimination of a small risk over significant reduction of a larger one.
Affect heuristic
Making decisions based on current emotions rather than objective analysis.
Choice overload
Too many options lead to decision paralysis or worse choices.
Decoy effect
Adding an inferior option makes another option seem more attractive.
Rhyme-as-reason effect
Rhyming statements seem more truthful.
IKEA effect
Assigning greater value to things we created or assembled ourselves.
Peak-end rule
We judge experiences mainly based on their peak moment and ending.
Rosy retrospection
Remembering the past as better than it actually was.
Telescoping effect
Recent events seem more distant, while old events seem closer.
Leveling and sharpening
When retelling stories, we sharpen some details and flatten others.
Misinformation effect
Later information distorts memories of earlier events.
Cryptomnesia
Confusing others' ideas with your own, unconscious plagiarism.
Egocentric bias
Remembering the past in ways that present us in a better light.
Consistency bias
The belief that our current views have always been the same.
Self-serving bias
Attributing successes to ourselves and failures to external factors.
Fundamental attribution error
Attributing others' behavior to their character, but our own to circumstances.
Actor-observer asymmetry
Different explanations for the same behaviors in ourselves and others.
Just-world hypothesis
The belief that people get what they deserve.
In-group favoritism
Preferring members of your own group over outsiders.
Out-group homogeneity
Perceiving members of other groups as more similar to each other.
Moral credential effect
Past good deeds "entitle" us to later unethical behavior.
Belief perseverance
Maintaining beliefs despite evidence refuting them.
Semmelweis reflex
Automatic rejection of new evidence contradicting established norms.
Backfire effect
Contrary evidence strengthens existing beliefs instead of weakening them.
Reactive devaluation
Rejecting proposals simply because they come from an "opponent."
Naïve realism
The belief that we see the world objectively, while others are biased.
Bias blind spot
Recognizing biases in others but not in ourselves.
False consensus effect
Overestimating how many people agree with our views.
False uniqueness effect
Underestimating how many people have similar positive traits.
Illusion of control
The belief that we have influence over random events.
Illusion of validity
Excessive confidence in predictions based on consistent patterns.
Planning fallacy
Underestimating time, costs, and risks; overestimating benefits.
Hyperbolic discounting
Preferring smaller rewards now over larger ones later.
Present bias
Placing disproportionate weight on immediate benefits.
Projection bias
Assuming our current preferences will persist in the future.
Restraint bias
Overestimating our ability to resist temptation.
Impact bias
Overestimating the lasting emotional impact of future events.
Distinction bias
Overestimating differences when directly comparing options.
Functional fixedness
Difficulty seeing alternative uses for objects.
Denomination effect
Reluctance to spend large denominations compared to small ones.
Money illusion
Focusing on nominal value of money rather than real value.
Mental accounting
Treating money differently depending on its "category."
Bizarreness effect
We remember bizarre things better than ordinary ones.
Generation effect
We remember information we generated ourselves better.
Picture superiority effect
Images are remembered better than words.
Humor effect
Funny things are remembered better.
Spacing effect
Information spread over time is remembered better than cramming.
Serial position effect
Better remembering of first and last items on a list.
Suffix effect
Additional information at the end of a list weakens memory of last items.
Google effect
Poorer memory for information that can be easily searched online.
Next-in-line effect
Poor memory of what the predecessor said just before our turn.
Testing effect
Information is better retained when actively retrieved, not just read.
Tip-of-the-tongue phenomenon
The feeling that we almost remember a word but can't retrieve it.
Cheerleader effect
People seem more attractive in a group than individually.
Contrast effect
Our assessment of something changes depending on what it's compared to.
Focusing effect
Placing too much weight on one aspect of an event.
Frequency illusion (Baader-Meinhof)
After noticing something new, we start seeing it "everywhere."
Clustering illusion
Seeing patterns in random sequences of data.
Texas sharpshooter fallacy
Fitting a hypothesis to data after the fact, ignoring non-fitting data.
Survivorship bias
Focusing on successes, ignoring invisible failures.
Outcome bias
Judging decision quality based on outcome, not process.
Normalcy bias
Underestimating the probability and effects of a disaster.
Appeal to probability
Treating possibility as certainty.
Subadditivity effect
The sum of probabilities of detailed events > probability of the general event.
Murphy's law
"Whatever can go wrong, will go wrong" - selective memory of failures.
Curse of knowledge
Difficulty imagining that someone doesn't know what we know.
Illusion of transparency
Overestimating how well others can read our emotions.
Hard-easy effect
Overconfidence in hard tasks, underconfidence in easy ones.
Above-average effect
Most people consider themselves better than average (mathematically impossible).
Worse-than-average effect
In very difficult tasks, people underestimate their abilities.
Defensive attribution
Blaming victims to protect ourselves from anxiety.
Trait ascription bias
Perceiving ourselves as more variable than others.
Effort justification
Assigning greater value to things that required a lot of effort.
Ben Franklin effect
People who have done us a favor like us more.
Bystander effect
The more witnesses, the lower the chance someone will help.
System justification
Tendency to defend the status quo and existing systems.
Well-traveled road effect
A familiar route seems shorter than an unfamiliar one of the same length.
Cross-race effect
Difficulty distinguishing faces of people from other ethnic groups.
Negativity bias
Negative information has greater impact than positive.
Positivity effect
Older people remember and notice more positive information.
Forer effect (Barnum effect)
Accepting general descriptions as accurately describing oneself.
Pygmalion effect
Higher expectations lead to better performance.
Golem effect
Lower expectations lead to worse performance.
Placebo effect
Expectation of an effect causes an actual change.
Nocebo effect
Negative expectations cause negative effects.
Mere exposure effect
We prefer things we have frequent contact with.
Propinquity effect
We more often befriend people physically close to us.
Similarity-attraction effect
We like people similar to us.
"Beautiful is good" stereotype
Attributing positive character traits to attractive people.
Ambiguity effect
Avoiding options with unknown probability.
Risk compensation
Increasing risky behavior when feeling safer.
Peltzman effect
Safety regulations lead to riskier behavior.
Pseudocertainty effect
Different decisions for the same problem depending on framing.
Omission bias
Perceiving harm from action as worse than equal harm from inaction.
Commission bias
Tendency to act even when inaction would be better.
Unit bias
Tendency to eat/use the whole "unit" regardless of its size.
Law of triviality (bikeshedding)
Spending disproportionately much time on trivial issues.
Rhyme as reason effect
Rhyming statements seem more true.
Continued influence effect
Debunked information continues to influence our thinking.
Illusory correlation
Seeing relationships between unrelated events.
Selection bias
Drawing conclusions from non-representative data.
Observer-expectancy effect
Researcher expectations unconsciously influence study results.
Ostrich effect
Avoiding negative information.
Information bias
Seeking more information than needed for a decision.
Automation bias
Excessive trust in automated systems.
Digital amnesia
Forgetting information that can be found on the internet.
Psychological reactance
Opposition to something when we feel our freedoms are being restricted.
Reverse psychology
Using reactance for manipulation.
Naïve allocation
Dividing resources equally instead of optimally.
Less-is-better effect
Preferring smaller quantity of high quality over larger quantity of mixed quality.
Conjunction effect
Separate evaluation of products gives different results than joint evaluation.
Identifiable victim effect
Greater empathy toward a specific person than a group.
Scope insensitivity
Lack of proportional response to differences in scale.
Compassion fade
Decline in empathy as the number of victims increases.
Identifiable perpetrator effect
Greater anger at a specific perpetrator than at an abstract system.
Denomination effect
Greater tendency to spend small change than bills.
Drop-in-the-bucket effect
Giving up on action because it seems insignificant given the scale of the problem.
Zero-sum bias
Treating situations as zero-sum games when they are not.
Proportionality bias
Expecting proportionality between cause and effect.
Congruence bias
Testing only direct hypotheses, ignoring alternatives.
Belief bias
Evaluating an argument based on the believability of the conclusion.
Expectation bias
Perceiving things according to expectations.
Attentional bias
Selectively paying attention to certain stimuli.
Selective perception
Perceiving reality through the lens of one's own beliefs.
Wishful thinking
Believing something because we want it to be true.
Empathy gap
Underestimating the influence of emotional states on decisions.
Moral luck
Judging morality based on outcome, not intention.
Rule of three
Three examples seem more convincing than one or two.
Spotlight effect
Overestimating how much others notice us.
Illusion of asymmetric insight
Believing we understand others better than they understand us.
Naive cynicism
Assuming others are more self-interested than they actually are.
Disposition effect
The tendency to sell assets that have gained value too quickly while holding onto assets that have lost value for too long.
Horns effect
The opposite of the halo effect — one negative trait makes us perceive a person or product as worse in every way.
Zeigarnik effect
We remember uncompleted tasks better than completed ones, which causes intrusive thoughts about them.
Inertia bias
The tendency to maintain the current state of affairs due to the effort required for change, even when change would be beneficial.
Pro-innovation bias
Overvaluing the usefulness of a new technology or innovation while ignoring its limitations.
Primacy and recency effects
Better recall of items from the beginning (primacy effect) and end (recency effect) of a list or presentation.
Context effect
The surrounding environment and situational context influence how we perceive and evaluate information.
Premature closure
Accepting the first explanation or solution without considering alternatives, especially under time pressure.
Emotional contagion
Unconsciously absorbing other people's emotions, which influences our decisions and assessments of situations.
Facial feedback effect
Our facial expressions influence the emotions we feel — smiling can improve mood, while frowning can worsen it.
Scarcity bias
Assigning greater value to things that are rare or have limited availability.
Time pressure bias
Making worse decisions under the influence of artificial or real time constraints.
Narrative commitment
Once we publicly tell our decision story, it becomes harder to change it, even when new facts emerge.
Conflict avoidance bias
Choosing options that minimize confrontation, even at the cost of a better solution.
End-of-history illusion
The belief that we have changed significantly in the past but are now essentially 'finished' and won't change much in the future.
Moral licensing
After doing something good, we allow ourselves worse behavior because we feel we've 'earned it'.
Narrative fallacy
Creating coherent stories from random events, assigning them false cause-and-effect relationships.
Not invented here syndrome
Rejecting ideas, solutions, or products from outside in favor of one's own, often inferior ones.
Pessimism bias
Systematically overestimating the probability of negative outcomes and underestimating positive ones.
Salience bias
Focusing attention on the most conspicuous features while ignoring less visible but more important aspects.
Social desirability bias
The tendency to present oneself favorably, answering according to social expectations rather than honestly.
Third-person effect
The belief that media and advertising influence others, but not ourselves.
Von Restorff effect
An item that stands out from a group of similar items is remembered better than the rest (isolation effect).
Stereotyping bias
Attributing characteristics of an entire group to a specific individual without considering their individuality.
Weber-Fechner law bias
We perceive change proportionally, not absolutely — the same amount of savings feels better on a cheap product than an expensive one.
Automation bias
Excessive trust in results generated by automated systems or AI, even when they are incorrect.
AI authority bias
Treating AI responses as authoritative and reliable, despite models being capable of hallucination and error.
Algorithmic aversion
Rejecting an algorithm's recommendations after seeing one error, despite it being statistically better than humans.
AI anchoring effect
The first AI suggestion becomes an anchor around which we build further thinking, limiting creativity.
Output length bias
Longer and more detailed AI responses are perceived as more credible, even when they are incorrect.
AI personification bias
Attributing human traits to AI — empathy, intention, understanding — which leads to excessive trust.
Prompt framing effect
How you phrase a question to AI drastically changes the response, but users treat each answer as objective.
AI sycophancy bias
AI models tend to agree with users and tell them what they want to hear, rather than the truth.
Reductionism bias
Oversimplifying complex problems to a single factor, ignoring the interdependencies of many variables.
Illusion of explanatory depth
We believe we understand complex mechanisms much better than we actually do, until we have to explain them.
Duration neglect
We judge experiences based on their peaks and endings, ignoring total duration.
Extrinsic incentive bias
We believe others are mainly motivated by money, while we ourselves are driven by values and passion.
Illusion of control (extended)
The belief that we can influence random events, especially when personally involved.
Irrational escalation
Continuing to invest in a failing project because 'we've put in too much to back out now'.
Telescoping effect
Recent events seem further in time, while distant events seem closer than they actually are.
Leveling and sharpening
When passing on information, certain details are omitted (leveling) while others are exaggerated (sharpening).
Somatic marker hypothesis
The body sends emotional signals (tension, gut feelings) that unconsciously influence our decisions.
Family pressure bias
Making decisions that align with family expectations rather than one's own needs and values.
Perspective gap
The inability to understand the perspective of someone in a different emotional state or life situation.
Urgency effect
Choosing urgent tasks over important ones, even when urgent tasks deliver less value.
Effort heuristic
Assigning greater value to things that required more effort — regardless of actual quality.
Curse of expertise
Experts can't imagine how people without their knowledge think, making their communication incomprehensible.
Ambiguity aversion
We prefer known risks over unknown ones — we prefer a certain 50% chance over an unclear 'maybe more'.
Hindsight bias
The belief that 'I knew it all along' once we know the outcome — falsifying memory of our own predictions.
Self-serving bias
Attributing successes to ourselves (internal traits) and failures to external circumstances.
Simulation heuristic
We judge the probability of events based on how easily we can mentally simulate them. The easier a scenario is to imagine, the more probable it seems.
Recognition heuristic
If we recognize one of two options, we automatically assign it higher value. Recognition = quality in our minds.
Regression to the mean
After an extreme result (very good or bad), the next one tends to be closer to the average — but we look for causes of this 'decline' or 'improvement' where there are none.
Scope neglect
We don't feel a proportional difference between small and large numbers. 10 victims and 10,000 victims trigger similar emotional responses.
Attribute substitution
When facing a hard question, we unconsciously substitute it with an easier one. Instead of 'Is this a good investment?' we answer 'Do I like it?'.
Reciprocity bias
We feel obligated to return a favor, even if it was small or unwanted. A powerful manipulation tool.
Commitment and consistency bias
After making even a small commitment, we feel internal pressure to be consistent — even when it's irrational. The 'foot in the door' technique.
Liking bias
We more easily comply with people we like — those who are physically attractive, similar to us, or who compliment us.
Unity principle
People from our identity group (family, nation, school) have disproportionately large influence on us. 'Our people' sound more convincing.
Default effect
People rarely change the default option — whoever sets it effectively makes the decision for you.
Zero price effect
'Free' triggers an irrationally strong preference. The difference between $0 and $1 is psychologically huge — bigger than between $1 and $2.
Filter bubble
Social media algorithms show you content confirming your views, creating the illusion that 'everyone thinks this way'. Amplifies confirmation bias.
Doomscrolling effect
Compulsive scrolling through negative news, even though it worsens mood and distorts our worldview.
Attention economy bias
In the battle for your attention, shocking and emotional content wins, not the most important. This distorts your view of reality.
Comparison trap
You compare your real life to the idealized versions of others' lives on social media.
Phantom vibration syndrome
You feel your phone vibrating when it's not there. Your brain has learned to expect notifications and 'produces' them.
Abilene paradox
A group makes a decision nobody actually agrees with — because everyone assumes the others want it.
Risky shift (group polarization)
Groups make more risky or extreme decisions than individuals — group discussion radicalizes positions.
Information cascade
People mimic predecessors' decisions, ignoring their own information. The more people follow a trend, the harder it is to resist.
Shared information bias
Groups mainly discuss information that everyone already knows, ignoring unique knowledge held by individual members.
Winner's curse
The winner of an auction or tender typically overpays — because winning means your valuation was the highest (and probably inflated).
Fixed pie bias
The belief that negotiations are a zero-sum game — what I gain, you lose. Ignores win-win possibilities.
BATNA neglect
Ignoring your alternatives in negotiations makes you accept worse terms than you need to.
Impostor syndrome
The belief that your successes are due to luck, chance, or fraud — and that you'll 'soon be exposed'.
Introspection illusion
We believe we know the real reasons for our decisions — but research shows we often fabricate explanations after the fact.
Metacognitive myopia
The inability to evaluate the quality of our own thinking. We don't know what we don't know — and can't verify it.
Anticipatory regret
You avoid making decisions out of fear of future regret. The paradox: not deciding is also a decision — often a worse one.
Emotional reasoning
Treating your own feelings as evidence of facts. 'I feel it's true, so it must be true.'
Affect labeling effect
Simply naming the emotion you're feeling reduces its intensity. Awareness of a bias is the first step to a better decision.
Declinism
The belief that things were better in the past and are now getting worse. Combines with nostalgia and selective memory.
Diagnosis momentum
An initial diagnosis or label gains 'momentum' — the more people repeat it, the harder it becomes to question.
Feature positive effect
We notice the presence of something more easily than its absence. Missing information, unasked questions — they're invisible.
Arbitrary coherence
The first price you see shapes all subsequent price expectations — even if it was random.
Catastrophizing
Automatically predicting the worst possible outcome, even when evidence barely supports it. 'If I lose this job, I'll never find another and end up homeless.' This distortion paralyzes action and amplifies anxiety.
Dichotomous thinking (black-and-white)
Seeing the world in 'all or nothing' terms — success or failure, perfect or hopeless. No room for shades of gray. Aaron Beck described this as a fundamental cognitive distortion in depression.
Mind reading bias
Assuming you know what other people think — without asking them. 'They definitely think I'm stupid.' One of the most common errors in interpersonal relationships, described by Aaron Beck.
Fortune telling bias
Predicting a negative outcome for a future event and treating that prediction as fact. 'No point applying — they won't hire me anyway.' A self-fulfilling prophecy, because you give up before trying.
Magnification and minimization
Exaggerating the significance of negative events while downplaying positive ones. Your mistakes are enormous, your successes — 'no big deal.' Also called the 'binocular trick' in cognitive therapy.
Disqualifying the positive
Rejecting positive experiences as 'irrelevant' or 'accidental.' 'I got promoted? Probably because nobody else wanted the job.' Maintains a negative self-image despite evidence of success.
Overgeneralization
Drawing sweeping conclusions from a single event. 'I failed this exam — I'm terrible at everything.' Aaron Beck identified this as a key cognitive distortion. One failure becomes proof of global inadequacy.
Personalization bias
Taking full responsibility for events over which you had minimal influence. 'The team lost — it must be my fault.' The opposite of self-serving bias — here you blame yourself for everything bad.
Should statements (tyranny of shoulds)
Imposing rigid rules on yourself and others: 'I must,' 'I should,' 'one ought to.' Karen Horney called this the 'tyranny of the shoulds.' Generates guilt when you fail your own unrealistic standards, and frustration toward others.
Mental filtering
Focusing exclusively on the negative aspects of a situation while ignoring everything positive. Like a filter that only lets through bad news. Aaron Beck described this as a mechanism that maintains depression.
Post-purchase rationalization
After making a purchase, you convince yourself it was a good decision — even if objectively it wasn't. The mind reduces cognitive dissonance by seeking arguments 'for' and ignoring those 'against.' The more expensive the purchase, the stronger the rationalization.
Nirvana fallacy
Rejecting practical solutions because they aren't perfect. Comparing real options to an unattainable ideal leads to inaction. 'No point running for 15 minutes — it's an hour or nothing.' Perfect is the enemy of good.
Prosecutor's fallacy
Incorrectly reversing conditional probability. 'The probability of this evidence given innocence is 1 in a million, so the defendant is 99.9999% guilty.' But it ignores the question: how many people in the population match this profile?
Professional deformation
Viewing the world exclusively through the lens of your profession. A lawyer sees legal risks everywhere, a marketer — campaigns, a doctor — symptoms. 'If all you have is a hammer, everything looks like a nail' — Abraham Maslow.
G.I. Joe fallacy
The belief that knowing about a problem is enough to solve it. 'I know it's a cognitive bias — so it doesn't affect me.' But awareness of a bias doesn't automatically protect you. Active strategies are needed, not just knowledge.
Pareidolia
Seeing meaningful patterns — especially faces — in random stimuli. The face on Mars, the Virgin Mary on toast, a rabbit in the clouds. Evolutionarily useful (better to see a face that isn't there than miss a predator), but leads to false conclusions.
Apophenia
Perceiving meaningful patterns and connections in random, unrelated data. Broader than pareidolia — encompasses seeing conspiracies, 'signs of fate,' correlations where none exist. Klaus Conrad coined the term in 1958.