Free brain trainer · by Kove
Cognitive Bias Trainer
Your mind runs on shortcuts that quietly mislead you. Learn the 100 best-known cognitive biases — then play Spot the Bias, a quick-fire quiz where you read a real-life scene and name the bias behind it. Free, no sign-up, right in your browser.
01 Survivorship Bias Belief & evidence
We judge the odds from the winners we can see and forget the losers we can't. We study thriving startups, bestselling authors and the bullet-holes on returning warplanes — never the founders who went bankrupt, the manuscripts in the drawer, or the planes that never came back. Because failure is silent, every pattern we extract from success is inflated.
Counter before copying a winner, go find the graveyard — the many who did the same thing and failed.
02 Confirmation Bias Belief & evidence
The father of all biases. We welcome evidence that fits our beliefs and quietly explain away everything that doesn't. The investor reads only the bullish analyst; the dieter notes the one study that blesses chocolate. New facts don't update the view — they get filtered through it.
Counter write your beliefs down and actively hunt for disconfirming evidence. Treat the fact that wounds your theory as the most valuable one in the room.
03 Availability Heuristic Belief & evidence
We estimate how likely something is by how easily examples come to mind — not by the actual odds. After a plane crash dominates the news, flying feels deadly even though driving is far riskier. Vivid, recent and emotional events feel common; quiet, statistical risks feel rare.
Counter ask for base rates and frequencies, not headlines. The easy-to-recall is not the same as the likely-to-happen.
04 Anchoring Effect Choices & risk
The first number we hear secretly drags every later estimate toward it, even when it's arbitrary. Name a high sticker price and the "discount" feels generous; spin a wheel to a random number and people's guesses shift toward it. The anchor sets the gravity for the whole negotiation.
Counter set your own number first, or pause and ask what you'd estimate with no anchor at all. Don't let the other side draw the starting line.
05 Hindsight Bias Belief & evidence
Once we know how things turned out, we feel we knew it all along. The crash, the breakup, the election result — all "obvious" in retrospect, though nobody called them in advance. This rewriting of memory makes the world seem more predictable than it is and breeds overconfidence in our forecasts.
Counter keep a decision journal. Record what you actually predicted, then check it later — the past was murkier than memory claims.
06 Loss Aversion Choices & risk
Losses hurt about twice as much as equivalent gains feel good. We'll refuse a coin-flip to win €150 or lose €100, though the odds favour playing. This asymmetry makes us cling to losing stocks, bad jobs and dead relationships simply to avoid the sting of letting go.
Counter evaluate choices by where they leave you in total, not by the pain of giving something up. Reframe a loss as the price of a better position.
07 Sunk Cost Fallacy Choices & risk
We keep pouring money, time or effort into something because we've already invested so much — even when the future looks bleak. We sit through the bad film because we paid; nations stay in losing wars because of the soldiers already lost. The past spend feels like a reason to continue. It isn't.
Counter ignore what's already gone. Decide only on the future: knowing what you know now, would you start this today?
08 Social Proof Other people
When unsure how to act, we copy the crowd — assuming that if everyone's doing it, it must be right. Canned laughter makes jokes funnier; a busy restaurant pulls in more diners; bystanders freeze because no one else is moving. Useful in the savannah, dangerous in a stampede or a bubble.
Counter ask whether the crowd actually knows something, or is just watching the crowd. Popularity is not proof.
09 Authority Bias Other people
We defer to authority figures — doctors, bosses, men in lab coats — and switch off our own judgment. Milgram's subjects delivered "lethal" shocks because an experimenter told them to; co-pilots have flown planes into the ground rather than contradict a captain. The title silences the question.
Counter treat experts as inputs, not oracles. Ask how they could be wrong, and what their track record actually is.
10 Halo Effect Other people
One glowing trait spills over and colours everything else. Attractive people are judged kinder and smarter; a profitable company's CEO is praised as "visionary" — until profits dip and the same traits are damned as reckless. We let a single impression stand in for a careful, separate look at each quality.
Counter assess each attribute on its own evidence. Don't let charisma, beauty or a stock price write the whole report card.
11 Fundamental Attribution Error Other people
We explain others' behaviour by their character and our own by circumstance. The driver who cut you off is "a jerk"; when you do it, you were "running late." We overweight personality and underweight the situation — forgetting how powerfully context shapes what anyone does.
Counter before labelling someone, ask what pressures they might be under. Assume the situation explains more than you think.
12 Self-Serving Bias Self & ego
We take credit for successes and blame the world for failures. A winning trade proves our skill; a losing one was "bad luck" or "the market." This tidy arrangement protects the ego but corrupts learning, because we never trace our defeats back to our own decisions.
Counter when something goes right, ask what luck contributed; when it goes wrong, ask what you contributed.
13 Dunning–Kruger Effect Self & ego
The less competent we are at something, the more we overrate our skill — because the very knowledge needed to spot our mistakes is the knowledge we lack. Beginners feel like experts; true experts, aware of all they don't know, often feel like impostors.
Counter seek honest external feedback and objective tests. Confidence is not competence, and the gap is widest exactly where you feel surest.
14 Overconfidence Effect Self & ego
We are systematically more certain than we are right. Ask people for ranges they're "99% sure" contain the truth and reality falls outside far more than 1% of the time. Experts are often the worst, because expertise breeds confidence faster than accuracy.
Counter widen your ranges and shave your certainty. For any forecast, ask what would have to be true for you to be badly wrong.
15 Optimism Bias Self & ego
We believe bad things are less likely to happen to us than to others — and good things more likely. Smokers underrate their cancer risk; newlyweds put their odds of divorce at zero. The bias fuels courage and resilience, but also blind spots about real danger.
Counter for important risks, anchor on the statistical base rate for people like you, then adjust only with specific evidence.
16 Planning Fallacy Action & time
We chronically underestimate how long things will take and how much they'll cost, even after a lifetime of overruns. The kitchen remodel, the thesis, the Sydney Opera House — all blow past their deadlines because we plan for the best case and ignore everything that usually goes wrong.
Counter take the "outside view." Ask how long similar projects actually took for other people, and budget from that, not from your hopes.
17 Framing Effect Choices & risk
The same fact persuades or repels depending on how it's worded. "90% survive" sounds far safer than "10% die," though they're identical. Meat labelled "80% lean" beats "20% fat." We respond to the packaging, not the contents.
Counter restate any claim in its opposite frame. If the two versions pull you in different directions, you're reacting to words, not facts.
18 Endowment Effect Choices & risk
We value things more simply because they're ours. Hand someone a mug and they'll demand twice the price to sell it that they'd have paid to buy it. Ownership inflates worth, which is why we overprice our houses and hoard junk we'd never buy again.
Counter ask what you'd pay for the item today if you didn't already own it. If less than the asking price, let it go.
19 Status Quo Bias Choices & risk
We prefer things to stay as they are and treat any change as a risk, even when the change is clearly better. We keep the same insurance, the same bank, the same seat — because the current state feels safe and switching feels like a decision we could be blamed for.
Counter imagine you were starting fresh. Would you actively choose your current arrangement? If not, the status quo is a choice too.
20 Default Effect Choices & risk
Whatever option is pre-selected tends to win, because changing it takes effort and implies responsibility. Countries with opt-out organ donation have donor rates near 90%; opt-in countries languish near 15% — same people, different default. The box that's already ticked quietly decides for us.
Counter notice the default and ask if you'd actively pick it. Design your own defaults to make good behaviour the path of least resistance.
21 Base-Rate Neglect Belief & evidence
We fixate on vivid specifics and ignore the underlying odds. Told a shy, tidy man "loves order," we guess librarian over farmer — forgetting there are vastly more farmers. A "highly accurate" test for a rare disease still yields mostly false positives, because the disease is rare to begin with.
Counter always start from the base rate — how common is this in the population? — then adjust for the specific evidence.
22 Conjunction Fallacy Belief & evidence
We judge a detailed, plausible story as more likely than a broad one — though adding details can only lower the odds. Told about Linda, a former activist, most people rank "bank teller and feminist" as more probable than "bank teller," which is mathematically impossible. A vivid narrative feels truer than a bare fact.
Counter remember that every added condition makes a scenario less likely, not more. Specific stories are seductive, not probable.
23 Gambler's Fallacy Belief & evidence
We believe that after a run of one outcome, the opposite is "due." After five reds on the roulette wheel, black feels overdue — but the wheel has no memory; the odds reset every spin. We see independent events as if they balance each other out.
Counter ask whether the events are truly independent. If they are, the past tells you nothing about the next outcome.
24 Hot-Hand Fallacy Belief & evidence
The mirror of the gambler's fallacy: we believe a streak will continue because the person is "on fire." The basketball shooter who's made three in a row seems sure to make the fourth, and teammates feed him the ball — though the data often shows the streak was random.
Counter separate genuine skill from a run of luck. A hot streak in a random process predicts nothing about the next attempt.
25 Clustering Illusion Belief & evidence
We see patterns and clusters in what is actually random noise. Faces in clouds, "hot zones" of cancer cases that are statistical flukes, meaning in stock-chart squiggles. The brain is a pattern machine that would rather invent a signal than accept randomness.
Counter ask whether a truly random process would produce this clump just as often. Demand statistical significance before believing the pattern is real.
26 Regression to the Mean Belief & evidence
Extreme results tend to be followed by more average ones, for purely statistical reasons. The athlete on a record streak, the patient at peak pain, the worst-performing branch — all drift back toward normal on their own. We then wrongly credit whatever we did in between: the coaching, the remedy, the pep talk.
Counter when you intervene at an extreme, expect improvement anyway. Use a control group before claiming your action caused the change.
27 Neglect of Probability Choices & risk
We respond to the drama of an outcome but not to its likelihood. People will pay nearly as much to eliminate a tiny risk as a large one, and fear a one-in-a-million terror attack more than the daily drive to work. The size of the feeling swamps the size of the odds.
Counter multiply impact by probability. A scary outcome with negligible odds deserves negligible worry.
28 Scarcity Bias Other people
We want things more when they're rare or running out. "Only 2 left," "limited edition," "offer ends tonight" — scarcity signals value and triggers a fear of missing out that overrides judgment. Cookies in a near-empty jar taste better than the same cookies in a full one.
Counter judge a thing by its actual merits and price, as if it were freely available. Manufactured urgency is a sales tactic, not information.
29 Reciprocity Other people
A favour creates a debt we feel compelled to repay, even uninvited and even when repaying costs more than the gift was worth. The free sample, the charity's enclosed pen, the dinner before the sales pitch — all exploit our deep urge to balance the ledger.
Counter recognise an engineered favour for what it is. You can accept a gift graciously and still owe nothing.
30 Liking Bias Other people
We say yes more readily to people we like — and we like those who are attractive, similar to us, and who flatter us. Salespeople mirror your hobbies and praise your taste because liking lowers your defences. The merits of the deal barely change; your willingness does.
Counter when you notice yourself liking a counterpart unusually fast, separate the person from the proposal and judge the deal alone.
31 Contrast Effect Choices & risk
We judge things by comparison, not in absolute terms. A €100 shirt feels cheap beside a €2,000 suit; a decent house looks great after the agent shows you two dumps first. Place anything next to a worse option and it shines — which is exactly how the decoy gets sold.
Counter evaluate each option against your own needs and budget, not against whatever it's parked beside.
32 Cognitive Dissonance Self & ego
When our actions clash with our beliefs, the discomfort pushes us to rewrite the beliefs rather than admit the mistake. The fox who can't reach the grapes decides it was sour anyway. We talk ourselves into loving the choice we're stuck with, just to quiet the inner conflict.
Counter notice when you're suddenly rationalising a bad outcome. The relief of a tidy story is a clue you're soothing dissonance, not reasoning.
33 Paradox of Choice Choices & risk
More options can leave us paralysed and less satisfied. Shoppers shown 24 jams sample more but buy far less than those shown six. Abundance breeds anxiety, regret over the roads not taken, and impossibly high expectations no single choice can meet.
Counter set your criteria in advance, pick the first option that clears the bar ("good enough"), and stop looking. Don't chase the perfect one.
34 Present Bias (Hyperbolic Discounting) Action & time
We wildly overvalue the present and discount the future. Offered €100 now or €110 next week, many grab the €100 — yet few would refuse €110 in a year over €100 in fifty-one weeks. The same delay looms huge up close and shrinks at a distance, which is why we overeat, undersave and procrastinate.
Counter precommit. Lock in future-serving choices today (auto-savings, no junk food in the house) so present-you can't sabotage them.
35 Action Bias Action & time
When we feel uncertain or watched, we'd rather act than wait — even when waiting is wiser. Goalkeepers dive left or right on penalties though staying centre stops more shots, because diving feels better than standing still and conceding. Doing something soothes us; doing nothing feels like failure.
Counter ask whether action genuinely improves the odds. Sometimes the disciplined move is patience, and "don't just do something, stand there."
36 Omission Bias Choices & risk
We judge harmful actions as worse than equally harmful inactions. Parents who skip a vaccine that carries tiny risk feel safer than those who give it, even when not vaccinating endangers the child more. Letting something bad happen feels cleaner than causing it.
Counter weigh outcomes, not the act-versus-omit distinction. A bad result you allowed is still a result you're responsible for.
37 Outcome Bias Belief & evidence
We judge a decision by how it turned out, not by how sensible it was when made. A surgeon who took a reckless gamble that happened to work is hailed; a sound bet that lost is condemned. But good decisions can have bad luck, and reckless ones can get lucky.
Counter grade the decision on the information and odds available at the time, not on the result you can now see.
38 Illusion of Control Belief & evidence
We believe we influence outcomes that are really down to chance. People throw dice harder for high numbers, prefer lottery tickets they picked themselves, and feel a sense of mastery pressing a "door close" button that isn't even wired up. The feeling of control is comforting and largely fictional.
Counter sort what you actually control from what you don't, and focus your effort only on the former.
39 Self-Selection Bias Belief & evidence
The people who opt into something aren't a random sample, so conclusions drawn from them mislead. "Our customers love us" — but unhappy ones already left and never answered the survey. A poll of website visitors tells you about visitors, not the public.
Counter ask who is missing from the data. The silent dropouts and non-responders often carry the very information you need.
40 Association Bias Belief & evidence
We link things that merely co-occurred and let one taint or bless the other. We "shoot the messenger" who brings bad news, distrust a product because of a grim ad, or repeat a ritual that once preceded a win. The brain bundles unrelated events into cause-and-effect.
Counter separate the message from the messenger and the signal from the coincidence. Ask if there's any real mechanism connecting the two.
41 Narrative Fallacy (Story Bias) Belief & evidence
We can't resist turning facts into stories with neat causes and morals — and the better the story, the more we trust it. History, markets and lives are messy and largely random, but a tidy narrative ("he succeeded because he never gave up") feels like understanding when it's really just editing.
Counter distrust explanations that are too clean. Ask what facts the story leaves out, and how much was simply luck.
42 False Causality Belief & evidence
We mistake correlation for cause, and confuse which way the arrow points. Villages with more storks had more babies (both track population, not the stork myth). Fire trucks correlate with damage — they don't cause it. Two things moving together rarely means one drives the other.
Counter before claiming X causes Y, ask if Y causes X, or if a hidden Z drives both. Demand a mechanism, not just a match.
43 Recency Effect Memory & attention
The most recent information weighs too heavily because it's freshest in mind. We judge a long job interview by its last five minutes, a year of work by the latest quarter, a whole holiday by the rainy final day. The end overwrites the middle.
Counter for any judgment over time, deliberately recall the early and middle stretches before the recent ones crowd them out.
44 Primacy Effect Memory & attention
First impressions cast a long shadow. The traits we hear first about a person ("intelligent, then stubborn") shape us more than the same traits in reverse order. The opening of a CV, a date, or a pitch colours everything that follows, fairly or not.
Counter for consequential judgments, gather the full picture before deciding, and consciously revisit whether the opening still deserves its weight.
45 In-Group/Out-Group Bias Other people
We favour our own group and stereotype outsiders, even when the groups are arbitrary. Split strangers by coin toss into "blues" and "greens" and within minutes they'll trust their own and distrust the others. We overrate the variety inside our tribe and flatten everyone outside it into a type.
Counter notice when "us versus them" is doing your thinking. Judge people as individuals, not as flags of a category.
46 False-Consensus Effect Other people
We overestimate how many people share our views, tastes and habits. Because our own opinions feel obviously correct, we assume "most people" agree — and we're genuinely surprised to find majorities who don't. We mistake our bubble for the world.
Counter seek out and seriously weigh people who disagree. Your sense of "what everyone thinks" is mostly a reflection of who you know.
47 Groupthink Other people
A cohesive group's hunger for harmony suppresses dissent and kills good decisions. To preserve the warm consensus, members self-censor doubts, and the team marches confidently off a cliff — the Bay of Pigs, doomed product launches, boardroom disasters all share this signature.
Counter appoint a devil's advocate, invite anonymous objections, and have the leader speak last so the group doesn't just echo the boss.
48 Social Loafing Other people
We slack off in groups because individual effort is hidden in the collective result. In a tug-of-war, people pull less hard the bigger the team; in meetings and group projects, responsibility diffuses until everyone coasts and assumes someone else will carry it.
Counter make individual contributions visible and accountable. Smaller teams and named ownership shrink the place to hide.
49 Bystander Effect Other people
The more people present at an emergency, the less likely any one of them helps — each assumes someone else will, and reads the crowd's inaction as a sign nothing's wrong. A victim can be safer with one witness than with thirty.
Counter if you need help, point at one specific person and give a direct instruction. If you're a bystander, assume no one else will act — you act.
50 Spotlight Effect Self & ego
We overestimate how much others notice us. The stain on your shirt, the dumb comment, the bad haircut feel like they're under a spotlight — but everyone else is starring in their own movie and barely registers yours. We are the centre of our world and a footnote in everyone else's.
Counter remember that people think about you far less than you fear. That's not bleak; it's freedom to take more risks.
51 Illusion of Transparency Self & ego
We assume our inner states leak out more than they do. The nervous speaker feels their panic is obvious; the liar feels their guilt is written on their face — yet observers usually can't tell. We know our own turmoil so vividly that we forget it's invisible to others.
Counter when anxious, remember your feelings aren't broadcast. If you want something understood, say it plainly rather than assuming it shows.
52 Curse of Knowledge Self & ego
Once we know something, we can't imagine not knowing it — so experts explain badly, tappers of a tune are baffled that listeners can't name it, and writers assume readers share their context. Our own knowledge blinds us to the gap in everyone else's.
Counter assume less shared context than feels natural. Test explanations on real beginners and watch where they get lost.
53 Forer (Barnum) Effect Belief & evidence
We accept vague, flattering descriptions as uniquely true of us. Horoscopes, personality tests and cold readings work because lines like "you have great untapped potential, yet can be self-critical" fit almost everyone. We mistake universal generalities for personal insight.
Counter ask whether the description could equally fit your neighbour — or its opposite. If it fits everyone, it reveals nothing about you.
54 Affect Heuristic Belief & evidence
We let a quick emotional reaction stand in for analysis. If something feels good, we judge its benefits high and risks low; if it feels bad, the reverse — regardless of the facts. Our gut answers "how do I feel about it?" and passes that off as "how risky is it?"
Counter when a snap feeling decides a complex question, slow down and price the actual risks and benefits separately.
55 Negativity Bias Memory & attention
Bad weighs heavier than good. One insult outlasts ten compliments; a single bad review sinks a string of raves; losses, threats and criticism grab the mind and won't let go. Useful for surviving predators, corrosive for relationships, teams and your own mood.
Counter deliberately count the positives, which the brain discounts. Give good news the extra weight your wiring withholds.
56 Peak–End Rule Memory & attention
We remember an experience by its most intense moment and its ending, not its average or duration. A colonoscopy that ended gently is recalled as better than a shorter one that ended at peak pain. The story memory tells can diverge sharply from what we actually lived through.
Counter design experiences with strong finishes, but for big life choices, weigh total quality and length — not just the highlight reel.
57 Focusing Illusion Memory & attention
"Nothing in life is as important as you think it is while you are thinking about it." Whatever we focus on swells in significance — the raise, the move to California, the new car. We predict these will transform our happiness, yet once they're normal life, we barely notice them.
Counter before chasing a single change, ask how much of your day it would really occupy once the novelty fades.
58 Mere Exposure Effect Memory & attention
We like things more simply because we've seen them before. Repeated faces, songs, brands and even nonsense words grow on us with familiarity alone. It's why advertising repeats, why incumbents have an edge, and why your least favourite song becomes tolerable by the tenth play.
Counter distinguish genuine quality from mere familiarity. Liking something you've seen often is not the same as it being good.
59 IKEA Effect Self & ego
We overvalue things we built ourselves. The wobbly bookshelf we assembled, the strategy we drafted, the code we wrote — our labour inflates our sense of their worth and blinds us to their flaws. Effort becomes love, and love becomes a poor judge.
Counter get an outsider with no sweat invested to assess your creation. Be willing to scrap what you toiled over.
60 Not-Invented-Here Syndrome Self & ego
We favour our own ideas and dismiss outside ones, even when the outside solution is better. Teams rebuild what they could have bought, reject a rival's good practice on principle, and fall in love with home-grown plans purely because they're home-grown.
Counter judge ideas by merit, not origin. Deliberately go shopping for solutions others have already proven.
61 Reactance Other people
When we feel our freedom threatened, we push back — sometimes against our own interest. Tell people not to do something and the forbidden thing becomes more tempting; the "Romeo and Juliet effect" deepens love that parents oppose. The harder the shove, the harder we dig in.
Counter notice when you're resisting just to assert autonomy. Ask whether you'd want this if no one had told you not to.
62 Decision Fatigue Action & time
The more decisions we make, the worse they get, as mental energy drains. Judges grant parole far more often early in the day and after meals than late in a tiring session; shoppers default to junk by the end of a long trip. A depleted mind reaches for the easy, lazy option.
Counter make important decisions when fresh, cut trivial choices with routines, and beware committing to anything when you're spent.
63 Zeigarnik Effect Memory & attention
Unfinished tasks nag at us and occupy the mind more than completed ones. The waiter recalls unpaid orders sharply, then forgets them the moment the bill is settled. Open loops — that unanswered email, that half-done project — drain attention until closed.
Counter you don't need to finish to free your mind — just make a concrete plan for the task. Writing down the next step quiets the nag.
64 Frequency Illusion (Baader–Meinhof) Memory & attention
Once you notice something, you start seeing it everywhere and assume it's suddenly common. Learn a new word, choose a car model, hear a baby name — and they seem to multiply overnight. Nothing changed but your attention, which now filters them in.
Counter remember that noticing more isn't the same as there being more. Your radar turned on; the world didn't shift.
65 Just-World Hypothesis Belief & evidence
We need to believe the world is fair, so we assume people get what they deserve — which curdles into blaming victims. The poor are deemed lazy, the assaulted "asked for it," the sick somehow at fault. Fairness is comforting, so we manufacture it even where there is none.
Counter accept that bad things happen to good people through luck and circumstance. Resist the urge to find a deserving fault.
66 Moral Licensing Self & ego
Doing one good thing gives us licence to do a bad one. We eat the salad, then "earn" the dessert; buy a green product, then waste more; affirm we're not prejudiced, then act with less restraint. A deposit of virtue feels like a balance we can spend.
Counter judge each act on its own. Past good behaviour is not a coupon for present lapses.
67 Ostrich Effect Action & time
We avoid information we expect to be unpleasant. Investors check their portfolios far less in down markets; people delay opening the medical letter, the credit-card bill, the performance review. Not looking feels like not suffering — until the avoided problem grows teeth.
Counter face bad news early, when it's smallest and most fixable. The discomfort of looking is almost always less than the cost of not.
68 Ambiguity Aversion Choices & risk
We prefer known risks to unknown ones, even at a cost. Offered a jar with a known 50/50 mix or one with unknown proportions, most pick the known — though the odds may be identical. We'll overpay for certainty and shun good opportunities simply because the odds are fuzzy.
Counter don't reject an option just because its probabilities are unclear. Estimate a range and decide on expected value, not on the discomfort of not knowing.
69 Certainty Effect Choices & risk
We overvalue outcomes that are certain and undervalue merely probable ones. We'll pay disproportionately to cut a risk from 5% to 0% versus 10% to 5%, and prefer a sure small win to a likely larger one. Zero risk has a magnetic, often irrational, pull.
Counter price the actual change in probability. Eliminating the last sliver of risk is rarely worth what certainty tempts you to pay.
70 House-Money Effect Choices & risk
We treat money we won as less "real" than money we earned, and gamble it recklessly. Up at the casino, we bet the winnings freely; flush from a bonus or a lucky trade, we take risks we'd never take with our salary. A euro is a euro, but its history changes how we spend it.
Counter once it's in your account, it's all just your money. Treat windfalls with the same care as wages.
71 WYSIATI (What You See Is All There Is) Belief & evidence
The mind builds confident stories from whatever information is in front of it and ignores the existence of what it can't see. We don't ask "what am I missing?" — we judge the world by the evidence at hand, however thin, and feel sure precisely because we can't imagine the gaps.
Counter ask "what would I need to know to be sure?" and "what's absent here?" Confidence should track the quality of evidence, not its mere availability.
72 Exponential Growth Bias Belief & evidence
Our minds think in straight lines, so we badly underestimate compounding. Fold a paper 50 times and we picture a thick book — it would reach the sun. The pond weed that doubles daily looks harmless until the day before it covers everything. Pandemics, debt and savings all blindside us this way.
Counter when something grows by a percentage, actually compute the doubling time and run the numbers out. Intuition is hopeless at exponentials.
73 Black Swan Neglect Choices & risk
We plan around the normal and ignore the rare, extreme events that actually shape history — crashes, pandemics, breakthroughs. Because they sit outside our experience, we deem them impossible until they arrive, then invent reasons they were obvious. The map of the expected omits what matters most.
Counter build in slack and redundancy for shocks you can't predict. Avoid fragile bets that a single rare event could wipe out.
74 Information Bias Belief & evidence
We crave more information even when it can't improve the decision. Doctors order tests whose results won't change the treatment; we research a purchase long past the point of usefulness. Gathering data feels like progress, so we do it instead of deciding.
Counter before seeking more facts, ask: "Will any possible answer change what I do?" If not, you already know enough — decide.
75 Effort Justification Self & ego
The harder we work for something, the more we value it — to justify the pain. Brutal initiations breed fierce loyalty; a course that nearly broke us feels precious; the meal we cooked for hours tastes better than it is. We can't believe we'd suffer for something worthless, so we inflate the worth.
Counter ask whether the thing is genuinely valuable, or just expensive in effort. Sweat is a sunk cost, not a measure of quality.
76 Incentive Super-Response Tendency Action & time
People respond to incentives — often far more strongly, and more literally, than intended. Pay to kill rats by the tail and people farm rats; reward bug-fixes and you get engineered bugs; bonus on quarterly numbers and the long term rots. The incentive, not the goal, is what actually gets optimised.
Counter when behaviour baffles you, ask "what's the incentive?" When designing one, war-game how it will be gamed.
77 Overjustification Effect Action & time
Paying people for what they already loved doing can kill the love. Reward children for drawing and they draw less once the reward stops; introduce fines or bonuses and intrinsic motivation withers. An external incentive crowds out the internal one it was meant to boost.
Counter protect intrinsic motivation. For work people do for meaning, think twice before bolting on money or metrics.
78 Hedonic Treadmill Memory & attention
We quickly adapt to good and bad fortune and drift back to our happiness baseline. Lottery winners and accident victims alike return, within a year or two, near where they started. The new house, the raise, the gadget thrill us briefly, then become the new normal we barely notice.
Counter invest in things resistant to adaptation — relationships, experiences, autonomy, gratitude — rather than chasing the next possession that will soon feel ordinary.
79 Envy Self & ego
We measure ourselves against others and resent those who have what we want — usually people close to us, not the distant super-rich. Envy is uniquely useless among the deadly sins: it brings no pleasure, only corrosion, and it sharpens precisely where comparison is easiest.
Counter compare yourself to your past self, not to peers. Widen or drop the comparison set, and turn envy into a clue about what you actually want.
80 Social Comparison Bias Other people
We resist helping or hiring those who might outshine us. Scientists are slower to cite rivals; managers avoid recruiting people more brilliant than themselves; the second-best singer sabotages the best. Protecting our relative rank quietly trumps building the strongest team.
Counter deliberately hire and promote people better than you. A-players who fear being outshone build B-teams.
81 Chauffeur Knowledge Belief & evidence
There are two kinds of knowledge: real understanding, and "chauffeur knowledge" — those who learned the talk. Planck's driver, the story goes, gave the physics lecture flawlessly from memory, then fielded a hard question by inviting the audience's "simple" chauffeur (the real Planck) to answer. Pundits and polished talkers often have only the script.
Counter probe with a hard follow-up question. Real experts say "I don't know"; chauffeurs bluster.
82 Twaddle Tendency Belief & evidence
When we have nothing real to say, we drown it in words. Verbose jargon, buzzwords and waffle masquerade as substance and intimidate the listener out of asking what was actually meant. The more uncertain the speaker, often the denser the fog.
Counter demand plain language and concrete claims. If something can't be said simply, the speaker may not understand it — or may be hiding that they don't.
83 Forecast Illusion Belief & evidence
Experts make confident predictions about the future and we keep believing them, despite their dismal record. Pundits who foresaw none of the big turns are invited back to forecast the next ones. Because forecasts cost the forecaster nothing when wrong, they're produced — and consumed — without accountability.
Counter track predictions and their hit rate. Trust forecasters with skin in the game and a scored record, not the loudest voice.
84 Inattentional Blindness Memory & attention
When attention is fixed on one thing, we go blind to the obvious. Viewers counting basketball passes famously miss a person in a gorilla suit strolling through the scene. Radiologists hunting tumours overlook a gorilla pasted into the scan. Focus is a spotlight that darkens everything outside it.
Counter periodically widen your gaze and ask "what am I not looking at?" Important things hide in plain sight while we concentrate elsewhere.
85 Introspection Illusion Self & ego
We trust our own self-examination as a pipeline to the truth, but it's an unreliable narrator. We confidently invent reasons for choices we made for hidden causes, and feeling sure of our motives doesn't make us right. Looking inward feels like seeing clearly; often it's just storytelling.
Counter treat your own introspective certainty with the same skepticism as others' claims. Test beliefs against outside evidence, not inner conviction.
86 Sleeper Effect Memory & attention
Over time we forget where information came from but remember the message — so even propaganda we initially dismissed can sway us later. The discredited source fades, the discounted claim lingers, and weeks on it feels like something we simply know. The warning label peels off; the content stays.
Counter tag dubious claims to their dubious source in memory, and be wary of "facts" you can't trace. Distrust outlives its own reasons.
87 Alternative Blindness Choices & risk
We compare the options put in front of us and forget the ones nobody mentioned. A salesman frames it as "this model or that one"; we choose between them, blind to the option of buying neither, or something else entirely. The unseen alternative is the one that's not on the menu.
Counter always ask "compared to what?" and generate options the situation didn't hand you — including walking away.
88 Salience Bias Memory & attention
We over-focus on whatever stands out — the loud, the colourful, the emotionally charged — and ignore quieter, more important factors. A dramatic anecdote outweighs dry statistics; a striking feature dominates a buying decision; the vivid risk eclipses the deadly mundane one. Prominence hijacks attention.
Counter deliberately list the unglamorous factors. Ask whether the thing grabbing your eye is actually the thing that matters most.
89 Procrastination Action & time
We delay important but unpleasant tasks in favour of trivial pleasant ones, even knowing we'll pay later. The report, the tax return, the workout slide while we tidy the inbox. It's present bias in action: future-us inherits the cost of present-us's comfort.
Counter set deadlines (public ones bite hardest), break tasks into tiny first steps, and remove distractions from arm's reach. Make starting easier than avoiding.
90 Domain Dependence Action & time
Insight learned in one area stubbornly fails to transfer to another. The risk-savvy entrepreneur ignores risk in his health; the doctor who preaches prevention skips her own checkups; the writer who edits ruthlessly can't cut his own emails. We compartmentalise wisdom and leave whole domains unwise.
Counter consciously port lessons across domains. Ask, "How would I handle this if it were a problem in my area of expertise?"
91 Will Rogers Phenomenon Belief & evidence
Moving an item from one group to another can raise the average of both — without anything actually improving. Reclassify mildly-ill patients as "sick," and both the healthy group (losing its worst) and the sick group (gaining its best) post better averages. The numbers improve; reality doesn't. Named for the quip that Okies moving to California raised the IQ of both states.
Counter when averages improve, check whether the categories were re-cut. Look at absolute outcomes, not just group means.
92 Cherry-Picking Belief & evidence
We showcase the data that flatters us and bury the rest. The company touts its one viral campaign and forgets the ten flops; the forecaster reminds you of the call that landed and not the misses. Highlighting hits while hiding misses turns a mediocre record into a triumph.
Counter ask for the full sample, including the failures and the denominator. A list of wins means nothing without the count of attempts.
93 Fallacy of the Single Cause Belief & evidence
We crave one tidy cause for events that have many. A war, a crash, a company's collapse gets pinned on a single villain or decision, when really dozens of factors converged. The single-cause story is satisfying, blameable and almost always too simple.
Counter assume multiple, interacting causes. Resist the first clean explanation and ask what else had to be true.
94 News Illusion Action & time
We consume a flood of news believing it makes us informed, but most of it is irrelevant to our lives and decisions, while it inflames anxiety and shreds attention. We can recall a hundred headlines and explain not one important thing better. Breaking news is to the mind what sugar is to the body.
Counter trade the firehose for depth — long articles, books, primary sources. Ask whether a story will change a single decision you make.
95 Neomania Action & time
We overvalue the new and shiny and underrate the old and proven. The latest gadget, framework or trend dazzles, while time-tested things seem dull. Yet most novelties vanish; what has survived a century will likely survive the next. The new is fragile; the old has already passed its tests.
Counter apply the "Lindy" lens — the longer something useful has lasted, the longer it's likely to last. Don't confuse novelty with progress.
96 Strategic Misrepresentation Choices & risk
When stakes are high and accountability low, people systematically lie in their forecasts to win approval. Project sponsors lowball costs and inflate benefits to get the green light; job seekers and pitch-makers do the same. It's not honest error — it's deliberate distortion baked into the process.
Counter discount optimistic estimates from anyone with an interest in your "yes." Compare against independent base rates and tie rewards to honest forecasting.
97 Pessimism Bias Self & ego
The flip side of optimism: in some moods and domains we overestimate the odds of disaster. The anxious overrate threats, the depressed expect failure, and whole cultures of doom-saying predict collapses that never come. Chronic gloom is as distorting as rose-tint, just less flattering.
Counter anchor expectations to base rates, not mood. Ask whether your dread reflects the evidence or just your current emotional weather.
98 Beginner's Luck Belief & evidence
Early wins fool us into believing we have a gift, tempting bigger bets just as luck runs out. The gambler who wins his first hands, the investor whose first picks soar, the founder whose first venture flies — all risk mistaking a short, random streak for durable skill.
Counter wait for a large enough sample before crediting skill. After early success, ask honestly whether you've proven anything yet.
99 Law of Small Numbers Belief & evidence
We draw sweeping conclusions from tiny samples, trusting small batches to mirror the whole. The smallest counties top both the highest- and lowest-cancer lists — not from any cause, but because small samples swing to extremes. Three good reviews, two anecdotes, one week of data feel like proof; they're noise.
Counter ask how big the sample is. Extreme results from small numbers are usually flukes, not findings.
100 Bandwagon Effect Other people
We adopt beliefs and behaviours because many others have — popularity itself becomes the reason. Fashions, fads, political surges and stock manias snowball as each adopter makes the next more likely, regardless of merit. "Everyone's jumping on" is mistaken for "this must be good."
Counter decide from the evidence as if you didn't know how popular something was. Momentum is not a measure of truth.