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The Abilene paradox occurs when a group collectively decides on a course of action that no individual member actually wants, because each person mistakenly believes the others want it and goes along to avoid conflict. Where groupthink is convergence on a leader's or majority's view, Abilene is unanimous agreement to something nobody prefers.
Absent-mindedness is forgetting an intended action or location because attention was elsewhere when the memory cue needed to be created.
Action bias is the tendency to favor doing something over doing nothing, even when there is no evidence that acting produces better outcomes — and sometimes when the evidence favors waiting. Action feels like competence and control; inaction feels like negligence, even when it is the optimal strategy.
The actor–observer bias is the tendency to attribute our own behavior to situational factors while attributing other people's behavior to their character. When I miss a deadline, it's because the week was chaotic; when you miss one, it's because you're disorganized.
The affect heuristic is the tendency to let an immediate feeling of 'good' or 'bad' stand in for a deliberate evaluation of risks and benefits. Things we like are judged to be low-risk and high-benefit; things we dislike are judged high-risk and low-benefit — even though in reality risk and benefit are often positively correlated.
Ambiguity bias is preferring a known risk over an unknown one, even when the unknown option may have equal or better expected value. Uncertainty about the probabilities themselves feels like extra danger beyond the outcomes at stake.
Anchoring is the pull of an initial number, price, or estimate on later judgment — even when the starting point is arbitrary. We adjust away from the anchor, but usually not far enough.
The anecdotal fallacy is treating one vivid story as evidence of a general rule while ignoring how representative the story is. An anecdote can make a possibility emotionally real; it cannot by itself establish frequency, cause, or typical outcome.
Anthropomorphism is interpreting an animal, object, system, or natural event through human intentions, emotions, or social traits.
The appeal to novelty is treating newness as evidence of superiority. A product, idea, or method feels like progress because it is new, even when its outcomes, fit, and reliability have not yet earned that conclusion.
The appeal-to-probability fallacy is treating a possible outcome as though it were inevitable simply because nothing rules it out.
The argument from fallacy, or fallacy fallacy, is concluding that a claim is false because someone made a bad argument for it. Bad reasoning fails to establish a conclusion; it does not establish the opposite conclusion.
Attentional bias is repeatedly noticing information that fits a current concern, goal, fear, or desire while giving less attention to other relevant signals.
Authority bias is giving a claim extra weight because it comes from a prestigious, powerful, or credentialed person, beyond what their relevant evidence and expertise justify. Authority becomes a substitute for checking the claim itself.
Automation bias is giving an automated recommendation more trust than its reliability and the surrounding evidence justify.
An availability cascade is a self-reinforcing cycle in which a claim or risk becomes more believed simply because it is more discussed: media coverage makes it mentally available, availability makes it feel true and important, which generates more coverage and social pressure to agree. Public perception can thereby detach almost completely from underlying facts.
The availability heuristic is judging frequency, danger, or importance by how easily examples come to mind. What is vivid, recent, emotional, or repeatedly covered by media feels common — even when the base rate says otherwise.
The backfire effect is the proposed possibility that a correction makes a false belief stronger rather than weaker. It became a popular explanation for polarized debate, but large studies suggest it is rare; resistance to correction is real, yet people usually become more accurate when given a clear correction.
The bandwagon effect is adopting a belief, product, or action because many other people appear to have adopted it. Popularity becomes a shortcut for truth, quality, or safety — and each new adopter makes the signal look stronger.
The base-rate fallacy is judging a specific case from a vivid clue while neglecting how common the outcome was before the clue appeared. A compelling story can feel more diagnostic than the numbers that should set the starting odds.
Belief bias is judging an argument's logic by whether its conclusion feels believable. A valid argument can be rejected because its conclusion seems false, while an invalid argument can be accepted because its conclusion matches what we already think.
Belief perseverance is the tendency to maintain a belief even after the evidence that originally supported it has been completely discredited. Once a belief exists, it recruits its own supporting structure — explanations, connections, identity — and survives the removal of its foundations.
The Ben Franklin effect is the tendency to like someone more after doing them a favor — rather than only doing favors for people we already like. The causal arrow runs backward from folk intuition: behavior shapes attitude.
The bias blind spot is readily detecting bias in other people while treating our own judgment as unusually objective. Because our reasoning feels sincere from the inside, the absence of a felt motive is mistaken for the absence of bias.
The bizarreness effect is remembering unusual or incongruous material better than ordinary material in some learning settings.
The bystander effect is the tendency for individuals to be less likely to help — or act at all — when other people are present. Responsibility diffuses across the group, everyone assumes someone else will step in, and each person reads the others' inaction as evidence that action isn't needed.
The certainty effect is the tendency to overweight outcomes that are certain relative to outcomes that are merely probable. Reducing risk from 5% to 0% feels far more valuable than reducing it from 10% to 5%, though both remove the same five points of probability — certainty carries a premium that distorts otherwise consistent preferences.
Change blindness is the failure to detect substantial changes to a visual scene when the change coincides with a brief disruption — a blink, a cut, a flicker, or a moment of occlusion. Large objects can be removed, swapped, or recolored without observers noticing, revealing how sparse our internal representation of the world really is.
The cheerleader effect is the finding that a face can be judged more attractive when seen in a group than when seen alone.
Choice overload is the phenomenon whereby having too many options can make deciding harder, reduce satisfaction with the chosen option, and sometimes prevent choosing at all. More choice is not monotonically better: beyond a point, each added option adds comparison cost, anticipated regret, and doubt.
Choice-supportive bias is revising memory so the option we chose looks better and the options we rejected look worse than they did at the time. The decision becomes evidence of its own quality.
The clustering illusion is seeing meaningful runs, clusters, or hot spots in data that random variation can produce on its own. Randomness is lumpy; we expect it to look more evenly mixed than it does.
Compassion fade is the tendency for empathy and willingness to help to decrease as the number of people in need increases. Concern peaks for a single identified individual and begins declining as early as the second person — the emotional inverse of what the arithmetic of suffering demands.
Confabulation is producing a confident, coherent account to fill a gap in memory or explanation without intending to deceive.
Confirmation bias is the tendency to treat evidence as a lawyer for what we already believe rather than a test of whether we are right. It shapes what we search for, notice, remember, and count as convincing — often without feeling like bias at all.
Congruence bias is testing a hypothesis only in ways that could confirm it, rather than seeking observations that might rule it out.
The conjunction fallacy is judging a detailed story as more likely than a broader category that includes it. A description can feel highly representative, but 'A and B' can never be more probable than 'A' alone.
Conservatism cognitive bias refers to the tendency of individuals to insufficiently revise their beliefs when presented with new evidence. This bias falls under the broader category of information overload, as people tend to give disproportionate weight to their prior knowledge or beliefs and do not adequately adjust them with fresh information. The phenomenon is closely associated with the psychological difficulty of abandoning previously held concepts and the innate preference for consistency.
The context effect cognitive bias refers to the influence that environmental factors can have on a person's perception and memory retrieval. When information is repeated in varied contexts, it can have an impactful influence on how effectively memory is encoded, stored, and later retrieved. Under the subcategory of repetition and memory is noticed, it highlights how external cues from the environment can either aid or hinder memory recall. Often associated with cue-dependent forgetting, the presence or absence of specific associative cues can determine the accessibility of memories.
The continued influence effect is using misinformation in reasoning after learning that it was false. A correction can update a stated belief while the original claim continues to supply the causal story that explains what happened.
The cross-race effect, also known as own-race bias, refers to the tendency for people to more easily recognize faces of their own race compared to faces of other races. This cognitive bias is prevalent in facial recognition tasks and has significant implications in various fields, such as criminal justice, psychological research, and social interactions.
Cryptomnesia is mistaking a remembered idea for an original one because its source has been forgotten.
The curse of knowledge is forgetting what it is like not to know something. Once information becomes obvious to us, we overestimate how much other people can infer, understand, or hear in what we say.
Decision fatigue is the claimed deterioration in decision quality after a long sequence of decisions: later choices drift toward defaults, avoidance, and impulsivity as the effort of active deciding accumulates. It is practically influential — and scientifically contested.
Declinism is the tendency to see a society, institution, or culture as broadly worsening while idealizing a selectively remembered past.
The decoy effect is a shift in preference caused by adding a third option that nobody should choose. The decoy makes one target option look clearly superior by comparison, even though it does not improve that option itself.
Defensive attribution is assigning blame in ways that protect your sense that the same misfortune could not happen to you.
The Delmore effect is the tendency to set clear, detailed, and articulate goals for the lower-priority areas of our lives, while our most important ambitions remain vague and unarticulated. Named after the poet Delmore Schwartz, it describes why people often have precise plans for minor tasks but only hazy intentions for the goals that matter most to them.
The denomination effect is spending the same amount of money more freely when it is divided into smaller, easier-to-part-with units.
A gain feels ready to celebrate; a loss feels easier to postpone. The disposition effect is investors’ tendency to sell winning positions relatively quickly while holding losing positions too long, even when the next decision should depend on future prospects rather than the purchase price.
Distinction bias is exaggerating the importance of small differences when options are compared side by side, even though the difference would barely matter in use.
The Dunning–Kruger effect is the debated finding that low performers can overestimate their ability, partly because the knowledge needed to perform a task also helps a person judge performance. The popular caricature — ignorant people are always supremely confident and experts always humble — goes far beyond the evidence.
Duration neglect is underweighting how long an experience lasted when remembering or choosing it. Retrospective evaluation often follows the peak and the ending more than the total amount of pleasure, pain, effort, or time.
Effort justification is valuing something more because getting it was costly, painful, or difficult.
Egocentric bias is overweighting your own perspective, effort, and role because it is more available to you than everyone else's.
The empathy gap is failing to appreciate how strongly a different emotional or bodily state will shape our own or another person's choices. Calm selves underestimate hunger, pain, fear, craving, anger, and stress; hot selves underestimate what calm reflection will want.
The end-of-history illusion is the tendency to believe that who we are right now is who we will remain — that our present values, preferences, and personality are the finished product, even while readily acknowledging how much we've changed in the past. At every age, people report substantial past change and predict minimal future change.
The endowment effect is valuing an item more once it is ours than we valued the identical item before owning it. Ownership changes the reference point: giving it up feels like a loss, while acquiring it had felt like a possible gain.
A bad bet can become harder to leave precisely because so much has already gone into it. Escalation of commitment is the tendency to add time, money, or reputation to a failing course in order to justify an earlier decision, rather than deciding from the remaining costs and expected benefits.
Essentialism is treating membership in a category as evidence of a fixed inner essence that explains how its members naturally are.
Extrinsic incentive error is overestimating how much other people are driven by visible rewards while underestimating interest, meaning, identity, and other internal motives.
Fading affect bias is the tendency for the emotional sting of many negative memories to fade faster than the warmth of positive ones.
The false-consensus effect is overestimating how many other people share your view, preference, or behavior.
A false memory is a remembered event or detail that is inaccurate or did not occur, yet can feel as vivid and sincere as a true memory. Memory is reconstructive: it combines fragments, meaning, expectation, later information, and source cues rather than preserving a perfect recording.
The focusing illusion is the tendency to exaggerate the importance of whatever we are currently thinking about. As Kahneman put it: nothing in life is as important as you think it is, while you are thinking about it. Attention inflates the weight of the attended factor in judgments of happiness, value, and choice.
The framing effect is changing a choice by changing its presentation while leaving the underlying facts the same. A 90% survival rate and a 10% mortality rate describe the same outcome, yet they invite different feelings, attention, and decisions.
The frequency illusion, often called the Baader–Meinhof phenomenon, is the sense that something suddenly appears everywhere after we first notice it. Attention changes what enters awareness, and the new sightings are mistaken for evidence that the world changed.
Functional fixedness is overlooking a useful solution because an object or idea is locked into its familiar role.
The fundamental attribution error is the tendency to explain other people's behavior by character while underweighting the situation they were in. We see the person clearly and the pressures, incentives, and missing information around them only dimly.
The gambler's fallacy is expecting an independent random process to correct itself in the next draw. After a streak, a reversal feels due — but a fair coin, roulette wheel, or lottery machine has no memory of the sequence.
The generation effect is remembering information better when we produce it ourselves rather than only reading or hearing it. Filling in an answer, completing a word, or explaining an idea creates a richer memory trace than passive exposure alone.
The Google effect, or digital offloading, is remembering where information can be found rather than remembering the information itself when we expect reliable access to it later. External memory changes what is worth encoding, not necessarily whether we can think.
Group attribution error is treating a group's average, a prominent member's act, or an official position as though it describes every individual in the group.
Groupthink is a mode of thinking in cohesive groups where the desire for harmony and consensus overrides realistic appraisal of alternatives. Members self-censor doubts, dissenters are pressured, and the group converges on a decision that many individuals privately question — while feeling more confident than any of them would alone.
The halo effect is letting one positive trait — attractiveness, prestige, polish, friendliness, a famous brand — spill into judgments about unrelated traits. A good first impression quietly becomes evidence of competence, honesty, or quality.
The hard-easy effect is a calibration pattern: confidence is often too high on difficult tasks and too low on easy ones.
Hindsight bias is seeing an outcome as obvious after it happens and remembering our earlier uncertainty as smaller than it was. Once we know the answer, it becomes hard to reconstruct a world in which the answer was still unknown.
Hostile attribution bias is the tendency to interpret ambiguous behavior by others as intentionally hostile. The bumped shoulder, the unanswered email, the terse comment — where intent is unclear, the biased reading defaults to malice, and the response escalates accordingly.
The hot-hand fallacy is seeing a run of successes and inferring that the next success is more likely, when the process has no memory. The classic sports example is now contested: some apparent streaks are real, so the question is not whether a run exists but whether evidence shows a mechanism behind it.
Hyperbolic discounting is the pattern in which a delay feels much more costly near the present than the same delay feels in the distant future.
The identifiable-victim effect is giving more help when need is represented by one known person than by an equally serious statistical description of many people.
We tend to value things more when we helped make them. The IKEA effect is the extra attachment or willingness to pay that can follow successful assembly, customization, or creation—even when an equivalent finished version would serve just as well.
The illusion of asymmetric insight is believing you understand other people more deeply than they understand you.
Having a choice can feel like having influence, even when chance or outside conditions determine the result. The illusion of control is the tendency to overestimate how much one’s actions affect an outcome that is largely random or externally constrained.
We normally experience our thoughts and actions as our own. An external-agency attribution is what happens when that sense of authorship is misplaced and an internal thought, choice, or feeling is instead credited to an outside person, force, or system. The label is most useful as a description of agency misattribution, not as a catch-all explanation for every belief about outside influence.
The illusion of transparency is overestimating how visible our thoughts, emotions, and nervousness are to other people. What feels loud inside often leaves only a faint external signal.
The illusion of validity is feeling confident in a judgment because the evidence forms a coherent story, even when it predicts poorly.
Illusory correlation is seeing a meaningful relationship between two things because their co-occurrences are vivid, even when the full data do not support one.
Illusory superiority is rating your own ability or character as better than most people's on a trait where that cannot be true for everyone.
The illusory truth effect is finding a repeated claim more believable because familiarity feels like evidence.
Impact bias is overestimating how intensely and how long a future event will affect our feelings. We imagine the promotion, breakup, purchase, or rejection in a spotlight, then underestimate adaptation and the rest of life that will quickly compete for attention.
Implicit associations are automatic links between social categories and concepts that can be measured in rapid-response tasks, whether or not a person endorses those links explicitly.
In-group bias is favoring people we see as 'us' over people we see as 'them,' even when group membership is arbitrary and the evidence about individuals is equivalent. Belonging can quietly become a proxy for trust, competence, and deservingness.
Inattentional blindness is the failure to notice a fully visible but unexpected object or event when attention is engaged elsewhere. We don't see with our eyes; we see with our attention — and attention is a narrow beam we systematically overestimate.
Information bias is seeking more information even when it will not change the decision. More data feels like progress and protection from regret, but it can add delay, noise, and a false sense of rigor without adding decision value.
Insensitivity to sample size is treating a striking result from a small sample as though it were as stable as the same result from a large sample.
The just-world hypothesis is the pull to believe that people get what they deserve, especially when unfairness would otherwise feel frightening or senseless.
The Lake Wobegon effect is the impossible pattern in which most people rate themselves above average on a valued trait.
The Law of Triviality, also known as Parkinson's Law of Triviality, describes a phenomenon where people give disproportionate weight and time to trivial issues while neglecting more complex and critical matters. This cognitive bias leads to decision-makers focusing on simple tasks that are easy to understand and discuss, rather than tackling the more significant issues that require deeper analysis.
A smaller option can look better when it is judged on its own, then lose as soon as it is placed beside a clearly superior alternative. The less-is-better effect is this preference reversal: people overweight an easy-to-evaluate cue and underweight total value in separate evaluation.
Leveling and sharpening are complementary memory changes: retellings lose qualifying detail while a few salient details become more central or exaggerated.
The levels-of-processing effect is remembering information better when we process its meaning and connections rather than only its surface form. Asking what an idea means, why it matters, or how it relates to prior knowledge usually creates a more durable memory than merely noticing its sound or appearance.
Loss aversion is the tendency for a loss to hurt more than an equivalent gain feels good. It makes keeping what we have psychologically compelling, even when a neutral comparison of future outcomes would favor a change.
The 'magic number' 7±2 is Miller's famous 1956 estimate of how many units people can hold briefly in mind. It is a landmark idea, not a bias — and it is too simple as a modern rule: capacity depends on chunking, rehearsal, familiarity, and the task, with tightly controlled estimates often closer to about four items.
The masked-man fallacy is wrongly treating a difference in what someone knows about two descriptions as proof that the descriptions refer to different things.
Memory inhibition is a cognitive bias involving the ability to keep irrelevant or redundant information from interfering with other cognitive processes, particularly recall. This form of selective forgetting allows individuals to focus on the most pertinent details by suppressing unnecessary or distracting data.
Mental accounting is treating identical money differently depending on its label, source, or imagined purpose.
The mere exposure effect is a psychological phenomenon where people tend to develop a preference for things they are repeatedly exposed to. This cognitive bias suggests that familiarity with something can lead to affection, even if it was initially neutral or disinterested.
The mere ownership effect is the tendency to evaluate an object more favorably simply because you own it — independent of any transaction. Where the endowment effect concerns what you'd charge to give something up, mere ownership shows that possession alone, even momentary and unchosen, makes things seem better.
Misattribution of memory is remembering information but assigning it to the wrong source, time, person, or context.
The misinformation effect is a change in memory after misleading information arrives following an event. Later wording, discussion, headlines, or suggestions can become blended with what a person originally saw, leaving a memory that feels direct but contains an introduced detail.
The modality effect is a short-term memory advantage for the final items of an auditory list over an equivalent visual list.
Money illusion is reacting to the number on a price tag or paycheck as though it were purchasing power, without adjusting for changing prices.
The moral credential effect is the temptation to treat a past good deed as proof that a questionable choice now cannot reflect badly on you.
Moral luck is judging identical choices more harshly or more favorably because chance made their outcomes different.
Motivated reasoning is the tendency to process information in ways that arrive at the conclusions we want to reach, while experiencing the process as objective. Desired conclusions get asked 'Can I believe this?'; undesired ones get asked 'Must I believe this?' — two very different evidentiary bars.
Murphy's Law is a useful engineering maxim, not a cognitive bias: if a failure mode is possible and left unguarded across enough opportunities, it may eventually occur.
We may grant our own motives their full complexity while treating other people’s motives as mostly self-serving. Naïve cynicism is the tendency to assume that others are more biased, strategic, or driven by private interest than we are.
Naïve realism is experiencing our own view as a direct reading of reality and explaining disagreement as ignorance, irrationality, or bias in the other person. We forget that our own attention, values, incentives, and prior beliefs also shape what looks obvious.
Negativity bias is giving bad news, criticism, threats, and losses more attention and weight than equally strong good news. One sharp negative signal can dominate a much larger body of positive or neutral evidence.
Neglect of probability is reacting to the size or vividness of a possible outcome while giving too little weight to how likely it is.
The Next-in-line effect is a cognitive bias where individuals have a diminished ability to remember information presented immediately before their turn to perform or speak, such as when they are in line to give a presentation or speak in a meeting.
Normalcy bias is treating an unfolding threat as if ordinary conditions will continue, especially when the alternative is disruptive or frightening. Because a disaster has not happened here before, warnings are discounted until the evidence becomes impossible to ignore.
Not Invented Here is discounting a useful external idea, tool, or solution because it came from outside the team or organization. Internal ownership feels like evidence of quality; external origin feels like a reason for suspicion.
Observer expectancy is when an evaluator's expectations quietly shape what participants do, what gets noticed, or how ambiguous results are scored.
Occam's razor is a reasoning principle, not a bias: when explanations fit the evidence equally well, prefer the one that adds fewer unsupported assumptions.
Omission bias is judging harm caused by action as worse than equal harm caused by inaction. Doing nothing feels morally cleaner because the causal role is less visible, even when the decision to refrain was itself a choice.
Optimism bias is expecting better outcomes for ourselves than for similar other people. We accept the general risk — layoffs, illness, delays, losses — while quietly treating our own case as the exception.
The ostrich effect is avoiding threatening information because looking at it feels worse, even when the information could improve the next decision.
Out-group homogeneity bias is seeing members of another group as more alike than members of our own group: 'they are all the same; we are a collection of individuals.' Distance hides variation while familiarity makes it visible.
Outcome bias is treating a decision as good because it worked out, or bad because it did not, even when the result depended heavily on luck.
Overconfidence is believing a judgment is more accurate, a skill stronger, or an outcome more controllable than the evidence warrants. Its most useful form is overprecision: confidence intervals that are far too narrow for how uncertain the world really is.
The overjustification effect is the tendency for extrinsic rewards to undermine intrinsic motivation: pay someone for what they already loved doing, and once the payment stops — or even while it continues — the love can fade. The activity's explanation shifts from 'I do this because I enjoy it' to 'I do this for the reward.'
Pareidolia is perceiving a familiar pattern—often a face, voice, or figure—in ambiguous or random input.
The peak-end rule is a cognitive bias that impacts how people retrospectively evaluate experiences. According to this rule, individuals tend to judge experiences based largely on how they felt at the most intense point (the peak) and at the end, rather than on the total sum or average of every moment of the experience.
Pessimism bias is forecasting negative outcomes as more likely, more severe, or less manageable than the available evidence supports.
The picture-superiority effect is remembering pictures more readily than equivalent words in many memory tasks. A concrete image can supply a distinctive visual trace as well as a verbal meaning, giving memory more than one route back to the item.
The placebo effect is a change in symptoms or experience caused by the meaning and expectation attached to treatment, rather than its active ingredient. It is not a cognitive bias in the strict sense: expectations can produce real changes, especially in subjective outcomes such as pain, while they are not a substitute for effective treatment of disease.
The planning fallacy is predicting a project from its best-case internal story while neglecting how similar projects actually went. We see the steps we intend to take and miss delays, rework, coordination costs, and the base rate of overruns.
The positivity effect is an age-related tendency, observed in some studies, to attend to and remember positive information more than negative information.
Post-purchase rationalization is defending a purchase after the fact so it feels more valuable and less regrettable. It is the consumer version of choice-supportive bias: the receipt turns a debatable option into 'the right choice.'
Prejudice is a negative or hostile evaluation of people because of their group membership. Unlike a stereotype, which is a generalized belief, prejudice includes an evaluative attitude that can shape attention, trust, and treatment before individual evidence is considered.
Present bias is the tendency to give disproportionate weight to immediate costs and rewards relative to future ones — beyond what any consistent discounting of the future would justify. We plan patiently for our future selves, then reliably overrule the plan when the moment arrives.
The primacy effect is remembering or overweighting what came first in a sequence. Early items receive more attention and rehearsal, and early impressions can become the frame through which later information is interpreted.
Pro-innovation bias is treating a new technology or idea as inherently beneficial while discounting its trade-offs, failure modes, and distribution of costs.
Projection bias is assuming that future preferences will resemble the preferences we feel right now. Hunger, excitement, loneliness, motivation, and fear masquerade as stable information about what our future selves will want.
Proportionality bias is the intuition that big events must have big causes — that a world-changing outcome cannot plausibly stem from a trivial, random, or lone-actor cause. It is a core engine of conspiracy thinking and of over-engineered corporate postmortems alike.
The pseudocertainty effect is treating a conditional or partial reduction in risk as though it creates certainty in the overall situation.
The Pygmalion effect is the phenomenon whereby higher expectations placed on a person lead to improved performance by that person. Expectations leak through behavior — attention, challenge, feedback, warmth — and become self-fulfilling; its dark twin, the Golem effect, is underperformance produced by low expectations.
Reactance is the urge to reassert freedom when a message, rule, or person feels controlling. A threatened option can become more attractive precisely because someone appears to be taking it away.
Reactive devaluation is discounting a proposal because it came from an opponent, rival, or distrusted source rather than because its terms are worse.
The recency effect is remembering or overweighting what came last because it is still active in short-term memory. The newest information can feel most representative even when it is only the latest item in a longer record.
The recency illusion is mistaking your first notice of a word, practice, or trend for the moment it began.
Regression to the mean is the statistical fact that extreme measurements tend to be followed by less extreme ones, simply because extremes are partly luck. The bias is our systematic failure to expect this: we attach causal stories — credit, blame, interventions that 'worked' — to changes that are just statistics doing what statistics does.
The representativeness heuristic is the tendency to judge the probability that something belongs to a category by how closely it resembles the typical member of that category, rather than by how likely it actually is. Because similarity is easier to assess than probability, we substitute one for the other — and ignore base rates, sample sizes, and chance in the process.
Restraint bias is overestimating how well your future self will resist a temptation, then placing that future self in its path.
Reverse psychology is a persuasion tactic that tries to trigger reactance by advocating the opposite of the outcome the persuader wants.
The rhyme-as-reason effect is the tendency for a rhyming claim to feel truer or wiser than an equivalent non-rhyming claim.
Risk compensation is increasing risky behavior after a safety measure makes danger feel lower, reducing some of the measure's benefit.
Rosy retrospection is remembering a past experience as better than it felt while you were living it.
Salience bias is the tendency to focus on information that is vivid, emotionally striking, or perceptually prominent while neglecting information that is duller but often more important. What grabs attention gets weighted; what doesn't, effectively doesn't exist for the decision.
Scope neglect is the tendency for our valuation of a problem to be nearly insensitive to its size. People will pay about the same to save 2,000, 20,000, or 200,000 birds; the emotional image driving the judgment — one oil-soaked bird — doesn't scale, so the numbers barely register.
Selective perception is noticing, interpreting, and remembering information through a filter shaped by what you already expect or believe.
Self-consistency bias is rewriting your past views to make your present self feel more coherent than it really was.
The self-relevance effect is the tendency to notice and remember information better when it is connected to yourself.
Self-serving bias is claiming personal credit for success while assigning failure to circumstances, luck, or other people. The same evidence gets two attribution rules, both of which protect a flattering view of the self.
The Semmelweis reflex is a cognitive bias wherein people tend to reject new evidence or knowledge if it contradicts established norms or beliefs. Named after Ignaz Semmelweis, a 19th-century Hungarian physician who discovered that hand-washing could drastically reduce childbed fever incidence, the term describes the tendency to dismiss or undervalue findings that conflict with accepted paradigms.
The Serial Position Effect is a cognitive bias that influences how people recall items from a list. This effect suggests that individuals tend to remember the first and last items in a series better than those in the middle. This phenomenon reveals key insights into human memory and information retention, providing a framework for understanding how we prioritize and recall data.
When a list is long enough to be difficult, its middle is often the least memorable territory. In immediate recall, people commonly recover more items from the beginning and end than from the center—a serial-position pattern rather than proof that the middle was unimportant.
Shared information bias is the tendency of groups to spend their discussion time on information all members already know, while the unique knowledge held by individual members — often the information that would change the decision — never surfaces. Groups exist to pool knowledge, and this bias is precisely the failure to pool.
Social comparison bias is devaluing or avoiding people who threaten our relative status, especially when we control an opportunity they could receive. A stronger candidate can feel like a risk to the self rather than an asset to the group.
Social desirability bias is giving the answer that looks respectable, safe, or acceptable rather than the most accurate answer.
The Spacing Effect is a cognitive phenomenon where learning is more effective when study sessions are spaced out over time rather than when completed in immediate succession. This phenomenon highlights how distributed practice produces more robust long-term memory retention compared to massed practice (i.e., cramming), influencing both formal education and informal learning activities.
The spotlight effect is overestimating how much other people notice, remember, or care about your visible mistakes and appearance.
Status quo bias is preferring the current arrangement because it is current, even when a fresh comparison would favor change. The costs of changing are vivid and immediate; the costs of staying put are familiar, dispersed, and easy to leave uncounted.
Stereotyping is using a broad belief about a group to infer traits, ability, motives, or behavior in a particular person. A category replaces individual evidence, often with more confidence than the evidence can support.
The streetlight effect is the tendency to search for answers where searching is easiest rather than where the answer is most likely to be — like the drunkard looking for his keys under the streetlight because 'that's where the light is.' In research and analytics, we measure what is measurable and quietly redefine the question to match.
The subadditivity effect is assigning a lower probability to a whole event than the probabilities assigned to its mutually exclusive parts add up to.
Subjective validation is finding a statement convincing because it feels personally meaningful, even when the statement is too vague to distinguish you from many others.
A final, irrelevant sound can steal the special advantage of the last few spoken items. This is the suffix effect: after an auditory list, a word such as “okay” can reduce recall of the end of the list, even though listeners know it is not one of the items.
Memory is reconstructed when we retrieve it, not replayed from a recording. Suggestibility is the tendency for wording, authority, repetition, or later information to shape what people report remembering or believing—sometimes adding a detail that was never part of the original event.
The sunk-cost fallacy is continuing a course of action because of time, money, or effort already spent, even though that investment cannot be recovered. The past feels like a reason to continue; economically, only the value and cost from this moment forward should decide.
Survivorship bias is drawing conclusions from the winners we can see while missing the failures that vanished from view. The visible sample feels like the whole population, so success looks more common — and more easily copied — than it really is.
System justification is the tendency to defend, rationalize, and see as legitimate the existing social, economic, and organizational arrangements one lives under — even when those arrangements work against one's own interests. The status quo isn't just preferred; it gets moralized.
The past does not arrive with date stamps. Telescoping is the tendency to place an event too recently (forward telescoping) or too far back (backward telescoping) when recalling when it happened. A vivid event can feel close even when it was years ago.
The testing effect is a cognitive phenomenon where long-term memory retention is improved through retrieval practice and self-testing. This effect suggests that the act of recalling information strengthens the memory trace more effectively than simply studying the material repeatedly.
The third-person effect is believing that media messages influence other people more than they influence you.
Time-saving bias is misjudging how much time a change in speed actually saves, especially when comparing rates rather than durations.
The tip-of-the-tongue phenomenon is the feeling of nearly retrieving a word or name while being unable to produce it. It is a memory-retrieval state, not a judgment bias in the narrow sense.
We often give ourselves a full situation and give other people a shorthand label. Trait ascription bias describes the tendency to explain our own awkward or harmful behavior by circumstances while treating a similar act by someone else as evidence of a stable character trait.
The ultimate attribution error is explaining your group's good outcomes by character and its bad outcomes by circumstance, while reversing that pattern for an out-group.
Unit bias is the tendency to treat one presented unit—a plate, packet, episode, or task—as the natural amount to finish.
The Von Restorff effect, also known as the isolation effect, is a cognitive bias that predicts an item noticeably different from others will be more likely to be remembered. This concept hinges on the principle that unusual or distinctive features enhance memory recall within a list of otherwise homogenous items.
A change is judged against its background, not in isolation. Adding one candle is obvious in a dark room but barely registers in a brightly lit one. The Weber–Fechner tradition describes this diminishing sensitivity: as a stimulus grows, a larger absolute change is often needed for people to notice a difference.
A familiar commute can feel short because it demands little attention; an unfamiliar route can feel long because every turn is new. The well-traveled-road effect is the proposed tendency to let that difference in experience shape estimates of duration or distance, sometimes favouring a familiar route even when it is not the quickest.
The Zeigarnik effect is the tendency to remember interrupted or incomplete tasks better than completed ones. Unfinished business keeps a background process running: the task intrudes on attention until it is either finished or given a concrete plan.
Zero-sum bias is assuming that another person's or group's gain must come at your expense, even when the situation can create value for more than one side.
Zero-risk bias is choosing to eliminate a small risk completely instead of reducing a much larger risk by more. Zero feels categorically safer than a small residual risk, even when the alternative leaves people safer overall.