November 2026
- Nov 9, 2026ConceptsThe Streisand Effect: How Suppression BackfiresThe Streisand effect explained: why trying to hide or censor information amplifies it, through reactance, information cascades, and the famous 2003 case.
- Nov 2, 2026ConceptsParkinson's Law: Work Expands to Fill the Time AvailableC. Northcote Parkinson published the line as Civil Service satire in The Economist in November 1955, backed by arithmetic: between 1914 and 1928 Royal Navy capital ships fell by roughly two thirds while Admiralty officials rose by nearly 80 percent. His mechanism was that officials multiply subordinates and then make work for each other. The article is candid that controlled experiments isolating the law are scarce, the support being convergent.
September 2026
- Sep 21, 2026ConceptsThe Map Is Not the Territory: Why Models MisleadBorges imagined cartographers so ambitious they drew a map the size of the empire, coinciding with it point for point, and later generations left it to rot in the desert. The fable's point is that a map's omissions are its function, not its defect, which is why adding detail rarely repairs a model that misled you. The article sorts the real failure modes into omission, bias and staleness, each with a guarding question.
- Sep 14, 2026ConceptsSecond-Order Thinking: Considering the Consequences of ConsequencesFrench colonial Hanoi paid for rat tails as proof, so people caught rats, cut off the tails and released them to breed, and officials began noticing tailless rats in the streets. The historian Michael Vann documented it from the colonial archives, which makes it the well-attested case where the Delhi cobra story Horst Siebert named in 2001 is not. Covers Bastiat and Merton on unanticipated consequences, the premortem, and where to stop the chain.
- Sep 7, 2026ConceptsOccam's Razor: When the Simplest Explanation WinsWilliam of Ockham never wrote the Latin sentence attached to his name; later writers coined it, and Aristotle had argued in the Posterior Analytics for the demonstration resting on fewer postulates. The razor earns its keep probabilistically, since each added assumption is another chance to be wrong, and statistically, since fewer parameters resist overfitting. Medicine keeps a counterweight: Hickam's dictum, that a patient can have as many diseases as they please.
July 2026
- Jul 24, 2026ConceptsThe Overton Window Framework: How Ideas Become Politically PossibleJoseph Lehman of the Mackinac Center put it bluntly: lawmakers are not in the business of shifting the Overton window, they are in the business of detecting where it is and moving into line with it. That is why activists, journalists and think tanks hold leverage elected officials lack. The window moves through anchoring with extremes, repetition, norm change and crisis, and none of those require persuading anyone that an idea is correct.
- Jul 18, 2026ConceptsThe Sunk Cost Fallacy: Why We Throw Good Money After BadSweis and colleagues reported in Science in 2018 that mice, rats and humans all showed sensitivity to sunk costs in a foraging task, and that the bias appeared only after the decision to pursue a reward had been made, not in the deliberation before it. Arkes and Blumer's 1985 theatre study showed the same pull: season ticket holders who paid full price attended more plays than discounted buyers seeing identical performances.
- Jul 15, 2026ConceptsThe Premortem: Imagining Failure Before It HappensMitchell, Russo and Pennington reported in 1989 that people told an outcome had already happened generated roughly 30 percent more possible reasons for it than people asked what might happen. The study measured the quantity and richness of reasons, not their accuracy. Gary Klein built the meeting around that effect, and its second engine is social: once failure is assumed, the sharpest critic wins the exercise instead of looking disloyal.
- Jul 12, 2026ConceptsThe Availability Heuristic: Why Vivid Beats LikelyAsked whether K appears more often as the first or third letter of English words, most people in Tversky and Kahneman's 1973 study said first; in typical English text it is roughly twice as common in third position. Recall ease, not frequency, drove the answer. Schwarz and colleagues sharpened the point in 1991: people asked for six examples of their own assertiveness rated themselves as more assertive than people asked for twelve.
- Jul 9, 2026ConceptsThe Anchoring Effect: How the First Number Shapes the RestKahneman describes an experiment where people estimated a redwood's height after being given either 1,200 feet or 180 feet, anchors 1,020 feet apart. Their mean estimates came out at 844 and 282 feet, a gap of 562 feet, so roughly 55 percent of the distance between the anchors passed into the answers, which Kahneman calls typical. The defenses with a track record: consider the opposite, and commit to your own number first.
June 2026
April 2026
March 2026
- Mar 13, 2026ConceptsThe Curse of Knowledge Explained: Why Experts Misjudge What Beginners KnowKnowing something well distorts your estimate of what others know. The page separates the bias from the illusion of transparency, false consensus and tacit knowledge, and reviews the Newton, Nickerson, Camerer and Hinds evidence along with its limits. In Newton's 1990 tapping study, tappers predicted about half of listeners would name the tune; roughly 2.5 percent did. The fixes are procedural: list assumed prerequisites, test with real readers.
- Mar 12, 2026ConceptsFraming Effects: How Presentation Changes MeaningIn 1981 Tversky and Kahneman described the same disease program two ways. Seventy-two percent of subjects chose the option saving 200 for certain over an equivalent gamble, while seventy-eight percent chose the gamble over 400 dying for certain. Identical math, opposite risk appetite. Also here: Levin and Gaeth on 95 percent fat-free beef, and Johnson and Goldstein's opt-out donation rates of 85 to 99 percent against 4 to 28 percent for opt-in.
- Mar 5, 2026ConceptsWhy Most Decisions Fail Due to Poor FramingFraming decides which decision you are making; analysis only decides how. Paul Nutt spent 20 years studying roughly 400 strategic decisions and reported that about half ended in failure, the most common cause being poor problem formulation rather than poor analysis: decision-makers evaluated options before defining the problem. The page catalogs five framing traps, reframing techniques, and how Kodak framed digital photography as a threat to contain.
July 2025
June 2025
January 2025
- Jan 19, 2025ConceptsSystem Justification Theory and Its Social ImplicationsKay and Jost found that poor but honest worked the same way, while unhappy poor exemplars did not, so the compensating virtue was doing the ideological work. As the page puts it, that is not compassion but rationalization dressed as recognition. It also takes its critics seriously, noting that anger-framing increases collective action, so justification is one possible response to unfairness rather than an inevitable one.
- Jan 10, 2025ConceptsProspect Theory: Why Framing Changes How Outcomes FeelTversky and Kahneman's 1981 disease problem put the same numbers two ways: 72 percent picked the certain option when it was framed as 200 lives saved, while 78 percent picked the gamble when it was framed as 400 deaths. The 1979 Econometrica model behind that reversal, its value and probability weighting functions, the disposition effect in Odean's brokerage data, and the limits: coefficients vary by country, and awareness alone does not switch the effect off.
- Jan 8, 2025ConceptsMental Accounting: Why a Dollar Is Not Always a DollarRichard Thaler's 1985 framework says we sort money into separate psychological accounts with their own spending rules, even though a dollar buys the same thing everywhere. Prelec and Simester found bidders offered roughly twice as much for the same sporting event tickets when told they would pay by credit card rather than cash. The same architecture explains sunk cost escalation, tax refund splurges, and why a labeled envelope protects savings better than a mental note.
- Jan 4, 2025ConceptsImplicit Bias: Exploring Unconscious PrejudicesGreenwald, McGhee and Schwartz published the Implicit Association Test in 1998. Participants sorted faces and words into paired categories, and White participants reporting low explicit prejudice were reliably faster when White faces shared a key with pleasant words. Many showing the largest implicit preference called themselves egalitarian. Project Implicit has since collected data from over 17 million people, alongside fierce methodological criticism.
- Jan 2, 2025ConceptsCognitive Dissonance Reduction StrategiesParticipants who told a stranger a tedious pegboard task was interesting rated it more positively afterward when they had been paid one dollar than twenty, because the small payment left them no outside justification for the lie. That is the insufficient justification effect, and it shows the mind revising belief rather than behavior. The page maps Festinger's four routes, including simply trivializing the inconvenient fact.
- Jan 1, 2025ConceptsAnchoring and Adjustment: Influence of Initial NumbersExpertise does not buy immunity. In Northcraft and Neale's 1987 Tucson study, professional real estate agents appraising the same property varied by roughly $14,000 across manipulated listing prices, students by about $22,000, and the agents almost uniformly denied the listing price had swayed them. Strack and Mussweiler's 1997 selective accessibility account explains why: the anchor primes memory for anchor-consistent facts before adjustment even begins.
December 2024
- Dec 29, 2024ConceptsPsychological Reactance: Why Bans BackfirePennebaker and Sanders put two signs on university restroom walls in 1976: one read "Do not write on these walls under any circumstances," the other "Please don't write on these walls." Two weeks later the commanding sign had collected substantially more graffiti. Jack Brehm named the mechanism in 1966: a threatened freedom gains value, and the threatener attracts hostility. Rains's meta-analysis of 20 studies put the effect around r of .30.
- Dec 21, 2024ConceptsAttribution Theory: Misunderstanding ActionsJones and Harris had Duke students read essays for and against Castro's Cuba in 1967. Half were told the writer chose the position; half were told the experimenter assigned it. Logically an assigned essay reveals nothing about belief, and participants knew that. They still rated pro-Castro writers as personally more pro-Castro. The situational constraint was acknowledged then ignored, which is the fundamental attribution error.
- Dec 17, 2024ConceptsThe Mere Exposure Effect: Why Familiarity Breeds LikingRobert Zajonc's 1968 experiments showed that nonsense words, Chinese characters, and strangers' faces were rated more pleasant the more often they had been shown, with no reward attached. Robert Bornstein's 1989 meta-analysis of 134 studies found an average effect of r = 0.26 and, counterintuitively, a stronger effect for subliminal exposure (r = 0.39) than for consciously visible exposure (r = 0.23).
- Dec 16, 2024ConceptsThe Just-World Hypothesis: Understanding Victim BlameMelvin Lerner had observers watch a woman receive fake electric shocks for memory errors in the mid-1960s. She had done nothing wrong and was assigned her role by chance. Observers did not respond with sympathy: they rated her less attractive, less likable and worse in character than before, and the more she suffered the worse they judged her. Lerner and Simmons published it in 1966. Believing the world is fair requires believing victims deserved it.
- Dec 15, 2024ConceptsThe False Consensus Effect: Misjudging Social NormsBoth groups read their own choice as the common one, and both cannot be majorities. Part of the cause is ordinary social sorting, since the people available in memory are unrepresentative of the population. The page also notes the odd pairing with false uniqueness, where the same person treats their opinions as widely shared while treating their abilities as exceptional, and that accurate distributional data reduces the bias without eliminating it.
- Dec 12, 2024ConceptsUnderstanding Cognitive Bias: Irrational JudgmentsPeter Wason showed Oxford undergraduates the sequence 2, 4, 6 in 1960 and asked them to find the rule by proposing sequences of their own. They offered 8, 10, 12 and declared confidently it was even numbers or constant intervals. The rule was any three ascending numbers. Almost nobody proposed something like 3, 11, 47, which would have tested the theory rather than confirmed it. Biases are systematic, so they compound rather than cancel.
- Dec 11, 2024ConceptsThe Self-Serving Bias: Taking Credit, Avoiding BlameThe teaching session was identical in both conditions and only the fabricated feedback differed, so the attribution flipped with the outcome. The page also corrects a statistic almost everyone misreports: the famous above-average driving figures come from Svenson, not Cross, whose 94 percent result was about college teachers rating their own teaching. It covers group-level attribution, cultural moderation, and where depressive realism actually applies.
- Dec 9, 2024ConceptsMoral Licensing: How Good Deeds Allow Bad BehaviorThe practical lever is how the earlier act is read. Treated as a credential that proves you are good, it licenses a later lapse; treated as an expression of values you hold, it does not, because values are not used up by expressing them. The page reports its own limits honestly, noting that Blanken's meta-analysis of 91 studies found a smaller effect than the headline experiments implied, with publication bias detected.
- Dec 5, 2024ConceptsIllusory Correlation: Patterns that Mislead Our MindsLoren and Jean Chapman built Draw-a-Person test packets in which no drawing feature had any statistical association with any symptom, then handed them to practicing clinicians and to undergraduates. Both groups confidently reported the pairings their culture had taught them to expect: large eyes with suspiciousness, muscular figures with worries about masculinity. The most experienced clinicians were the firmest believers.
- Dec 4, 2024ConceptsHindsight Bias ExplainedCaplan and colleagues gave physician reviewers anesthesia cases to judge. Reviewers told the patient had died rated the quality of care significantly lower than reviewers given clinically identical cases without that outcome. The same choices read as negligent or reasonable depending only on what the reviewer knew. Starting with Fischhoff and Beyth's Nixon-in-China study, this is why outcome knowledge rewrites memory, and why warnings barely dent it.
- Dec 3, 2024ConceptsThe Representativeness Heuristic: Judging by AppearancesAdding feminist activist to bank teller makes the description fit the prototype better while mathematically making it less likely, and people follow the resemblance. The page covers the cab problem and the engineer-lawyer studies, where vivid case detail swamps the base rate entirely. It also gives Gigerenzer's critique real weight, since presenting the mammogram problem as natural frequencies largely dissolves the error.
- Dec 2, 2024ConceptsThe Negativity Bias: Why Bad Is Stronger Than GoodSoroka, Fournier and Nir's 2019 PNAS study measured skin conductance and cardiac response to news clips and found negative clips produced larger physiological arousal in every one of 17 politically and culturally diverse nations, suggesting the asymmetry is not culturally learned. Gottman's lab put the ratio for enduring marriages near 5 positive interactions to 1 negative, while couples heading for divorce clustered around 0.8 to 1.
- Dec 1, 2024ConceptsWhat Is the Status Quo BiasJohnson and Goldstein's 2003 Science analysis of European organ donation found consent rates of 85.9 to 99.98 percent in opt-out countries against 4.25 to 27.5 percent in opt-in ones, with survey support for donation similar across them. Madrian and Shea's 2001 study of one company's switch to automatic 401(k) enrollment saw new-employee participation move from about 37 to 86 percent. The article separates the bias from rational switching costs.
November 2024
- Nov 29, 2024ConceptsChoice Overload: When More Options Produce Fewer DecisionsAt Draeger's Market in 1995, Iyengar and Lepper's 24-jam tasting table drew 60 percent of passing shoppers against 40 percent for the 6-jam table, yet 30 percent of those who stopped at six jams bought a jar versus 3 percent at twenty-four. The effect is real but conditional: Scheibehenne's 2010 meta-analysis of 50 studies found a mean effect size near zero, and Chernev's 2015 review of 99 studies pinned it to four moderators.
- Nov 28, 2024ConceptsThe Endowment Effect: Why We Overvalue What We OwnIn the autumn of 1990, Kahneman, Knetsch and Thaler handed Cornell students a bookstore coffee mug at random. Sellers would not part with theirs below a median of $7.12, while buyers offered a median of $2.87 for the identical object, and a third group choosing between mug and cash valued it at $3.12. Twenty minutes of possession moved the price by a factor of about 2.5 and falsified the Coase theorem's prediction that trade would clear.
- Nov 27, 2024ConceptsThe Overconfidence Effect: The Mistakes of the SmartAlpert and Raiffa asked people for ranges they were 90 percent certain contained the right answer. The truth fell outside those ranges roughly 40 to 50 percent of the time. The error is not boastfulness, it is compressed uncertainty, and Moore and Healy showed in 2008 that lumping it in with the better-than-average effect produced contradictions, since overplacement reverses on hard tasks while overprecision does not. Gigerenzer argues frequency formats shrink the gap.
- Nov 26, 2024ConceptsIn-Group Bias: The Psychology of Group FavoritismHenri Tajfel told Bristol schoolboys in 1971 they were Klee types or Kandinsky types, assigned effectively at random. They had never met their group, could not communicate, and stood to gain nothing personally. They still favored their own, and chose the maximum difference strategy: 7 points for us and 1 for them over 19 and 25, forgoing 12 points purely to widen the gap. Categorization alone, with no history or shared interest, produces favoritism.
- Nov 25, 2024ConceptsFraming Effect: How Presentation Influences DecisionsMcNeil, Pauker, Sox and Tversky gave 238 patients, 491 students and 424 physicians a choice between surgery and radiation for lung cancer, with identical data shown as survival or mortality figures. Surgical preference fell from 82 percent in the survival frame to 53 percent in the mortality frame, and the shift was statistically indistinguishable across groups. Trained physicians were as susceptible as medically naive patients. The words, not the numbers, did the work.
- Nov 23, 2024ConceptsWhat Is the Recency Bias: How Recent Events Distort JudgmentGoyal and Wahal examined over 3,400 pension funds across a decade and found they consistently hired investment managers after periods of strong recent performance and fired them after weak ones, with no improvement in subsequent returns from the hiring decisions. These are fiduciaries with professional teams and research budgets, making the same error as retail investors with far more money. Also covers the serial position effect and what actually corrects it.
- Nov 22, 2024ConceptsThe Optimism Bias: Why We Expect the Best OutcomesNeil Weinstein's 1980 study asked 258 undergraduates to compare their own odds of major life events against an average peer. They rated themselves below average on every negative event and above average on every positive one, knowing full well that not everyone can be below average. Tali Sharot's later work found the mechanism that keeps it going: beliefs update strongly toward good news about real risk and much more weakly toward bad news.
- Nov 21, 2024ConceptsGambler's Fallacy: Misconceptions About RandomnessTheir 2016 study found the same corrective pattern in loan officers approving applications and umpires calling pitches, controlling for the merits of each case. A roulette wheel has no memory, but the people watching it keep a ledger, and so do professionals trained for case-by-case objectivity. The page is careful on the hot hand too, noting Miller and Sanjurjo's 2018 correction and that the debate continues rather than treating it as settled illusion.
- Nov 20, 2024ConceptsThe Halo EffectNisbett and Wilson filmed a lecturer behaving warmly for one group and coldly for another, with identical lecture content. The warm-condition students rated his appearance, his accent and his mannerisms more favorably, then denied his warmth had affected those judgments. Their 1977 paper is why awareness is a weak defense: people invent independent reasons for a judgment a single impression produced. Thorndike saw the same pattern in 1920.
- Nov 19, 2024ConceptsAnchoring Bias: The First Number Shapes Your MindHow an arbitrary number bends judgment even when everyone knows it is meaningless. Kahneman and Tversky spun a wheel of fortune rigged to land on 10 or 65, then asked what percentage of African countries belong to the UN. Those who saw 10 averaged 25 percent; those who saw 65 averaged 45. Participants watched the wheel being rigged and still could not escape it, because adjustment from an anchor is typically insufficient.
- Nov 16, 2024ConceptsThe Fundamental Attribution ErrorIn 1967 Jones and Harris told participants that essay writers had been assigned their pro-Castro or anti-Castro position, which licenses no inference about the writer's actual views. Participants drew it anyway, and decades of replication failed to remove it. Gilbert, Pelham and Krull later showed why: the dispositional read is automatic and the situational correction is effortful, so participants running a memory task never corrected at all.
- Nov 14, 2024ConceptsConfirmation Bias: Why We Find What We're Looking ForIn 1979, Lord, Ross and Lepper gave supporters and opponents of capital punishment the identical pair of studies, one favoring deterrence and one undercutting it. Both groups rated the study that agreed with them as better designed, and both left holding their original view more strongly than before. Balanced evidence deepened the disagreement. The article traces the pattern from Wason's 2-4-6 task to Iraq, N-rays and Theranos.
- Nov 13, 2024ConceptsLoss Aversion: Why Losing $100 Hurts More Than Winning $150Kahneman and Tversky's 1979 prospect theory paper found that most people needed stakes of roughly $200 to $250 before accepting a coin flip risking $100. De Martino, Camerer and Adolphs, in PNAS in 2010, then studied two patients with focal bilateral amygdala damage: both tracked expected value and probability normally, yet both showed dramatically reduced loss aversion. Also covers Boston housing sellers, NFL fourth downs and the cultural variation in the coefficient.
- Nov 11, 2024ConceptsRegression to the Mean: Statistical Insights ExplainedA senior flight instructor told Kahneman that praising a clean maneuver was followed by worse flying and criticizing a sloppy one by improvement, so reward clearly did not work. He was right about what he saw and wrong about the cause. Extreme runs contain luck that does not repeat, so the next run drifts toward the pilot's true average whatever anyone says. An entire training culture had been built on evidence the mathematics produced by itself.
- Nov 10, 2024ConceptsThe Availability Heuristic and Media: Why What Comes to Mind Feels Like What Is TrueSchwarz and colleagues showed in 1991 that the feeling of retrieval matters more than what gets retrieved: people asked to recall twelve examples of their own assertive behavior rated themselves less assertive than those asked for six, because straining to reach twelve reads as evidence that assertiveness is rare. The cost can be counted: Gigerenzer estimated roughly 350 extra American road deaths in the three months after September 11, as travelers moved from planes to cars.
- Nov 9, 2024ConceptsDunning-Kruger Effect: Misjudging CompetenceMcArthur Wheeler robbed two Pittsburgh banks in 1995 with lemon juice on his face, convinced it made him invisible to cameras. Dunning was struck by the sincerity, not the brazenness. In the 1999 paper, bottom-quartile performers estimated the 62nd percentile and averaged the 12th; top performers guessed 68th and scored 86th. The popular stupid-people-think-they-are-smart curve distorts this: it is an asymmetric effect at the tails, about competence structure rather than ego.
- Nov 7, 2024ConceptsThe Map Is Not the Territory: Why Models Always LieLong-Term Capital Management managed 126 billion dollars of assets on 4.8 billion of equity, with two Nobel laureates among its partners, because it trusted models built on stable correlations. When Russia defaulted in August 1998 those correlations collapsed toward one, LTCM lost 4.6 billion, and the New York Fed brokered a 3.6 billion private bailout. The partners had not miscalculated; they had stopped seeing the model as a map.
October 2024
February 2024
December 2023
- Dec 21, 2023ConceptsHofstadter's Law: Understanding Time Management DelaysWhy knowing about the bias does not fix it. Hofstadter buried the line in his 1979 book and built it to be self-referential: the correction fails to correct, because what you have not thought of cannot be enumerated in advance. Kahneman and Tversky named the underlying planning fallacy the same year, and the practical remedy is the outside view, asking what similar projects actually produced rather than what your plan predicts.
- Dec 16, 2023ConceptsThink Critically: Science and Practical Steps for ReasoningWhat cognitive science says about where reasoning fails. Asch found in 1951 that roughly 75 percent of participants gave a clearly wrong answer at least once when surrounded by confederates, and 32 percent of all answers in the pressure condition matched the group over the evidence. Many afterwards reported genuine uncertainty about their own perception rather than simply caving. Calibration is the practical defense.
- Dec 14, 2023ConceptsWhy Smart People Make Irrational Financial ChoicesOne illustrative case: an engineer on $180,000 paying minimums on $22,000 of card debt while contributing to a matched retirement account, effectively borrowing at 22 percent to earn 3. He could explain compound interest fluently. What he could not explain was why his behavior diverged from what he knew. Fifty years of behavioral economics documents that gap as patterned, not random, and intelligence does not inoculate anyone.
November 2023
September 2023
August 2023
May 2023
December 2022
- Dec 29, 2022ConceptsWhat Is Narrative Fallacy: How Stories Mislead UsTaleb's term for imposing a causal story on a sequence of events, so a known outcome feels inevitable. Phil Rosenzweig documented it in strategy research: the same company, strategy and leader is described as brilliantly decisive when outcomes are good and recklessly overconfident when they are bad. Denrell's simulations found the performance patterns behind celebrated companies are consistent with random variation that then mean-reverts.
- Dec 23, 2022ConceptsDunning-Kruger Effect: Key Research and MythsWhat the Dunning-Kruger effect actually claims against the meme version. The familiar curve with a peak of Mount Stupid and a valley of despair appears nowhere in the 1999 paper and does not represent its findings; the real result was that bottom-quartile performers overestimated their percentile rank, with one study showing people at the 12th percentile estimating the 62nd. Whether statistical artifacts explain the pattern remains contested and probably partially true.
- Dec 22, 2022ConceptsUnderstanding Confirmation Bias in Decision-MakingConfirmation bias explained through the experiment that defined it. Peter Wason showed participants 2, 4, 6 and asked them to find the rule; almost all proposed only sequences that fit their first guess, so the actual rule, any ascending sequence, went undiscovered. Lord, Ross and Lepper found in 1979 that giving both sides the same mixed evidence on capital punishment made each group more confident, which means balanced information does not reliably correct bias.
- Dec 20, 2022ConceptsAvailability Heuristic Psychology: How This Cognitive Bias Works in the BrainPeople shifted from flying to driving because the attacks made air travel vividly available while road risk stayed invisible. The mechanism is retrieval ease standing in for frequency, which is why subjects judged homicide about as common as diabetes when diabetes kills roughly five times as many. Schwarz then showed it runs on felt effort: recalling twelve examples of your own assertiveness makes you feel less assertive than recalling six.
November 2022
October 2022
- Oct 15, 2022ConceptsPrice Anchoring: How Initial Numbers Influence ValueIn Tversky and Kahneman's 1974 Science paper, participants watched a wheel land on a number they knew was random, then estimated what share of UN countries are African. Those who saw 65 answered 45 percent at the median; those who saw 10 answered 25 percent. Northcraft and Neale later showed professional real estate agents anchoring on listing prices while insisting they were not. Decoy pricing and first-offer strategy follow from the same effect.
- Oct 11, 2022ConceptsBaader-Meinhof Phenomenon: The Frequency Illusion ExplainedA reader named Terry Mullen coined the term in a 1994 St. Paul Pioneer Press comment thread after hearing an unfamiliar name twice in days. Stanford linguist Arnold Zwicky named the same thing the frequency illusion in 2005. Selective attention creates the extra detections and confirmation bias misreads them as a change in the world. The illusion peaks shortly after first exposure and fades, which is how objective data distinguishes it from a real trend.
- Oct 7, 2022ConceptsSurvivorship Bias: The Hidden Graveyard of Failed EvidenceMilitary analysts wanted to reinforce where returning bombers were hit. Wald, at Columbia's Statistical Research Group, read the damage map as a conditional probability: the chance of a hit there given that the plane survived. The clean areas were the lethal ones. Elton, Gruber, and Blake put a number on another version of the same filter, estimating that survivorship-biased mutual fund databases overstated performance by roughly 0.9 percentage points a year.
- Oct 3, 2022ConceptsUnderstanding the Spotlight Effect: Perception BiasOverestimating how closely others are watching. Gilovich, Medvec and Savitsky documented this in 2000 with a T-shirt experiment at Cornell, where participants predicted about half the room would recall the image and 23 percent actually could. The same overestimation appeared when the shirts carried admired figures, which rules out simple fear of judgment. The mechanism is anchoring on your own vivid self-awareness and adjusting too little.
September 2022
- Sep 27, 2022ConceptsUnderstanding Exponential Growth and Our LimitationsWhy exponential growth defeats intuition. In the chessboard parable, doubling grains of rice reaches about half a million by the 20th square and roughly 2 billion by the 32nd, the halfway point, yet the 64th square alone exceeds 18 quintillion grains, more rice than human civilization has ever produced. Albert Bartlett delivered his lecture on this over 1,700 times between 1969 and 2013, calling exponential illiteracy a central intellectual failure.
- Sep 26, 2022ConceptsUnderstanding Availability Bias in InvestingMissing the 20 best days turned the return negative, and the best days cluster right beside the worst, because they are the rebounds that follow the panic. The fund flows show the pattern: while the S&P 500 recovered from its 2009 low, retail investors were net sellers of US equity funds every year from 2009 through 2012, buying back only in 2013 once the move was largely made.
- Sep 4, 2022ConceptsThe Spotlight Effect and Its Role in Social AnxietyGilovich's Cornell work found people overestimate their own salience by a factor of roughly two, because they anchor on their own vivid awareness and adjust too little. Clark and Wells explain the anxious version: attention turns inward, and a racing heart becomes the main evidence for how you look, which is a poor proxy. Rehearsing sentences to avoid stumbling is a safety behavior that often causes the stumble.
August 2022
- Aug 27, 2022ConceptsFluency Effect: Why Easy Processing Feels TrueMcGlone and Tofighbakhsh found the smoother phrasing read as truer regardless, which is why a well-typeset lie reads more credibly than a poorly typeset truth. Repetition does the same work, and Fazio found the illusory truth effect still operates in people who already hold the accurate knowledge. Knowing the right answer does not fully protect you, so repetition alone can raise the credibility of a false claim.
- Aug 25, 2022ConceptsThe Availability Cascade: Media Influence on PerceptionHow repetition becomes its own evidence. Kuran and Sunstein named the mechanism in the Stanford Law Review in 1999: a claim entering public discourse becomes easier to recall, which makes it feel more dangerous, which drives more coverage. The EPA's own worst-case estimate for Alar was between one in 100,000 and one in a million, within its acceptable range, yet supermarkets cleared their shelves. The article is careful to distinguish cascades from genuine risk.
July 2022
- Jul 20, 2022ConceptsImpact of Availability Heuristic in HealthcareHow the availability heuristic distorts medical judgment. Tversky and Kahneman described it in 1973: people estimate likelihood by how easily an example comes to mind rather than by statistics, demonstrated when participants wrongly judged K more common as a first letter than as a third. In healthcare the same mechanism drives over-testing, because symptom searches surface vivid serious diagnoses that dominate probability estimates regardless of base rates.
- Jul 3, 2022ConceptsRetrospective Sensemaking: How We Reconstruct Our PastKarl Weick's claim is that meaning is made backward: people act first and construct the account afterward, driven by plausibility rather than accuracy. Arkes and colleagues showed the cost in 1981, when physicians given a case's true diagnosis revised their recall of their own earlier confidence upward. You cannot judge a decision process you can no longer remember being uncertain about, which is why contemporaneous records matter.
- Jul 1, 2022ConceptsWhat Is the Default Effect: Why Pre-Selected Options WinJohnson and Goldstein compared eleven European countries and found survey support for donation was broadly similar while consent rates were not: Germany at 12 percent under opt-in, Austria at 99.98 percent under opt-out. Defaults cut both ways. Madrian and Shea found automatic enrollment lifted 401(k) participation from about 49 to 86 percent, then left many employees stranded at a default contribution rate well below what they needed.
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