404meanings Bias spotter
Bias spotter Bias spotter is ten short scenes from everyday life, each with a cognitive bias at work. Pick which of three it is, then read why, with a link to the full entry. It is practice in recognising the patterns, not a test of you: these are shortcuts everyone's thinking takes, and nothing you answer is kept.
Spot the bias 10 scenes Ten short scenes from everyday life. In each, someone's thinking takes a well-known shortcut: pick which of three biases it is, then read why. Keys 1 to 3 answer. A new round shuffles a fresh ten from 45 scenes.
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Every scene in the deck 45 scenes JavaScript is off in this browser, so here is the whole deck. Read each scene, choose from the three options, then open it to see the answer.
01 A jacket's tag says "Was £240, now £120". Maya had planned to spend about £60 on a jacket, but £120 suddenly feels like a bargain.
Anchoring Bias · Decoy Effect · Framing Effect
Open for the answer Anchoring Bias. The crossed-out £240 is the first price she saw, and it dragged her sense of a fair price upwards. That is anchoring: an earlier number pulls the judgement towards it, even when it is only there to persuade. Read the entry →
02 Before guessing how many sweets are in a jar, Tom is asked to write down the last two digits of his phone number: 87. His guess comes out far higher than his sister's, whose digits were 12.
Anchoring Bias · Availability Heuristic · Overconfidence Effect
Open for the answer Anchoring Bias. The phone digits have nothing to do with the jar, yet the number he had just written gave his estimate somewhere to start. Anchoring works even when the anchor is obviously irrelevant. Read the entry →
03 After a week of news coverage about a shark attack, Leo decides not to swim on holiday. He drives the two hours to the coast without a second thought.
Availability Heuristic · Confirmation Bias · Negativity Bias
Open for the answer Availability Heuristic. Vivid, heavily reported events come to mind easily, so they feel more likely than they are. The ordinary risks of the drive barely register, because nothing about them is memorable. Read the entry →
04 Asked whether more English words begin with K or have K as their third letter, Ana answers "begin with K" at once, because she can think of so many.
Availability Heuristic · Confirmation Bias · Primacy Effect
Open for the answer Availability Heuristic. Words are easier to call up by their first letter than by their third, so the first group feels bigger. She is judging how common something is by how easily examples come to mind, not by counting. Read the entry →
05 Priya learns the word "liminal" on Monday. By Friday she has seen it in a podcast title, a novel and two posts, and wonders whether it has suddenly become fashionable.
Apophenia · Baader-Meinhof Phenomenon · Mere Exposure Effect
Open for the answer Baader-Meinhof Phenomenon. The word was probably turning up just as often before. What changed is that she now notices it, which makes it feel as if it is suddenly everywhere. Read the entry →
06 Two restaurants sit side by side. One has a queue outside and the other is empty. Sam knows nothing about either, but the busy one looks far more tempting.
Bandwagon Effect · Halo Effect · Mere Exposure Effect
Open for the answer Bandwagon Effect. He is drawn to the choice that lots of other people have already made. A queue can be useful information, which is why the pull is strong, but Sam has no idea why anyone is in it. Read the entry →
07 The group chat runs a poll on where to eat. Kai waits to see which option is winning, then votes for that one.
Bandwagon Effect · False Consensus Effect · Status Quo Bias
Open for the answer Bandwagon Effect. Kai's vote follows the crowd rather than his own preference. Adopting a choice because you can see that many others already have is the bandwagon effect. Read the entry →
08 A free online quiz tells Ruth: "You can be sociable, but you also value time alone, and you sometimes doubt decisions you have made." She is amazed at how well it knows her.
Barnum Effect · Confirmation Bias · Spotlight Effect
Open for the answer Barnum Effect. Statements like these fit almost everybody, yet they read as a personal portrait. Accepting a vague, general description as uniquely about you is the Barnum effect. Read the entry →
09 Convinced that his new running shoes make him faster, Dev remembers every good run he has had in them and puts the slow ones down to the weather.
Confirmation Bias · Optimism Bias · Self-Serving Bias
Open for the answer Confirmation Bias. He keeps the evidence that fits his belief and explains away the evidence that does not. That uneven treatment of evidence is confirmation bias. Read the entry →
10 Lena has already set her heart on a particular phone. Before buying it, she searches for "best reviews" of that model, never for "problems".
Anchoring Bias · Confirmation Bias · Endowment Effect
Open for the answer Confirmation Bias. She is seeking out information that will agree with her, not information that might change her mind. Confirmation bias shapes what we look for, not only how we read it. Read the entry →
11 A gym offers three plans: off-peak only for £30 a month, full access with classes for £45, and full access without classes, also for £45. Far more people now choose the £45 plan with classes.
Anchoring Bias · Decoy Effect · Framing Effect
Open for the answer Decoy Effect. Nobody is meant to pick the plan without classes: it is plainly worse than the one beside it at the same price. Its job is to make that plan look like a bargain next to the off-peak option. That is a decoy. Read the entry →
12 After one beginners' chess lesson, Finn is sure he already plays better than most of the class. When they play each other, he finishes near the bottom.
Dunning-Kruger Effect · Self-Serving Bias · Spotlight Effect
Open for the answer Dunning-Kruger Effect. People with the least skill at something often rate themselves most generously against others. The finding is widely replicated; the usual explanation for it is contested, as the entry explains. Read the entry →
13 Ella would not have paid more than £10 for a concert mug. Once she is given one, she turns down an offer of £20 for it.
Endowment Effect · IKEA Effect · Sunk Cost Fallacy
Open for the answer Endowment Effect. Nothing about the mug changed except that it became hers. Asking more to give something up than you would have paid to get it is the endowment effect. Read the entry →
14 Ava cannot stand pineapple on pizza. She is astonished to learn that half the office loves it; she had assumed almost everyone agreed with her.
Bandwagon Effect · Confirmation Bias · False Consensus Effect
Open for the answer False Consensus Effect. She took her own taste as the norm. Overestimating how many people share your opinions and preferences is the false consensus effect. Read the entry →
15 Two pots of yoghurt are identical. One label says "95% fat-free" and the other says "5% fat". Shoppers rate the first as the healthier choice.
Anchoring Bias · Decoy Effect · Framing Effect
Open for the answer Framing Effect. The facts are the same; only the wording differs. Choosing differently depending on how identical information is presented is the framing effect. Read the entry →
16 One report says "nine out of ten trains ran on time". Another describes the same month as "one train in ten was late". Readers of the first rate the service far more kindly.
Availability Heuristic · Framing Effect · Negativity Bias
Open for the answer Framing Effect. Same trains, same month, two descriptions. Put as a success, the record sounds good; put as a failure, it sounds poor. That is framing. Read the entry →
17 A car cuts in front of Max on the motorway. "What an idiot," he says, without wondering whether the driver might have been rushing to an emergency.
Fundamental Attribution Error · Horn Effect · Negativity Bias
Open for the answer Fundamental Attribution Error. He explains the other driver's behaviour by their character and gives no weight to the situation they might be in. That is the fundamental attribution error. Read the entry →
18 When a new colleague misses a deadline, Rhea decides he is disorganised. She later learns he spent that week covering two other people's work.
Fundamental Attribution Error · Hindsight Bias · Horn Effect
Open for the answer Fundamental Attribution Error. She reached for a personality explanation before considering his circumstances. Underweighting the situation when judging someone else is the fundamental attribution error. Read the entry →
19 A fair coin has landed heads six times in a row. Ben puts his money on tails, because "it must be due".
Apophenia · Gambler's Fallacy · Hot Hand Fallacy
Open for the answer Gambler's Fallacy. A fair coin has no memory: each toss is still an even chance. Believing a run makes the opposite outcome due is the gambler's fallacy. Read the entry →
20 Kim avoids last week's winning lottery numbers, sure they are unlikely to come up again so soon.
Availability Heuristic · Gambler's Fallacy · Recency Bias
Open for the answer Gambler's Fallacy. In a fair draw, last week's numbers are exactly as likely as any others. Expecting a random process to balance itself out is the gambler's fallacy. Read the entry →
21 The new manager is charming and well dressed, so the team assumes she must also be good with budgets.
Halo Effect · Horn Effect · Mere Exposure Effect
Open for the answer Halo Effect. One good impression is spreading to qualities it says nothing about. Charm tells you nothing about budgeting; the halo effect makes it seem as if it does. Read the entry →
22 Josh finds a colleague's laugh irritating. Before long he has decided that her reports are sloppy and her ideas unoriginal too.
Halo Effect · Horn Effect · Negativity Bias
Open for the answer Horn Effect. One thing he dislikes is colouring his view of unrelated things. That is the horn effect, the halo effect running in reverse. Read the entry →
23 After her team loses the final, Grace says, "I knew they'd lose. It was obvious from the start." Before the match she had predicted a win.
Confirmation Bias · Hindsight Bias · Self-Serving Bias
Open for the answer Hindsight Bias. Knowing the result has rewritten her sense of what she expected. The feeling that an outcome was obvious all along is hindsight bias. Read the entry →
24 When two friends split up, everyone in the group remembers having seen it coming for months.
Bandwagon Effect · False Consensus Effect · Hindsight Bias
Open for the answer Hindsight Bias. Once an outcome is known, the signs that pointed to it look clearer than they did at the time. That is hindsight bias at work across a whole group. Read the entry →
25 Omar's home-made bookshelf leans slightly to the left, but he would not swap it for a sturdier one from a shop.
Halo Effect · IKEA Effect · Status Quo Bias
Open for the answer IKEA Effect. He values it more because he built it himself, even though an expert's would be better. That extra value from your own labour is the IKEA effect. Read the entry →
26 Walking down the street he has lived on for ten years, Arlo has a sudden, unsettling sense that it is a place he has never seen before.
Baader-Meinhof Phenomenon · Jamais Vu · Presque Vu
Open for the answer Jamais Vu. Something completely familiar briefly feels strange and new. That is jamais vu, the reverse of déjà vu. Read the entry →
27 After saying "spoon" out loud thirty times for a party game, Isla finds that the word has turned into an odd, empty noise.
Presque Vu · Semantic Satiation · Tip-of-the-Tongue Phenomenon
Open for the answer Semantic Satiation. Repeating a word over and over can drain its meaning for a while, leaving only the sound. That is semantic satiation. Read the entry →
28 Zara is offered a single coin toss: heads she wins £110, tails she loses £100. She turns it down, though on average the bet favours her.
Gambler's Fallacy · Loss Aversion · Optimism Bias
Open for the answer Loss Aversion. The possible loss of £100 feels heavier than the possible gain of £110. Losses looming larger than equal gains is loss aversion. Read the entry →
29 Hana disliked an advert's jingle at first. After hearing it every morning for a month, she catches herself humming it fondly.
Baader-Meinhof Phenomenon · Mere Exposure Effect · Recency Bias
Open for the answer Mere Exposure Effect. Nothing about the jingle improved; she simply heard it a lot. Growing to like something through familiarity alone is the mere exposure effect. Read the entry →
30 Kofi's review has nine compliments and one criticism. That evening, the criticism is all he can think about.
Confirmation Bias · Negativity Bias · Spotlight Effect
Open for the answer Negativity Bias. One negative comment outweighs nine positive ones. Bad information hitting harder and lasting longer than equally strong good information is negativity bias. Read the entry →
31 At a wedding, the guests agree that plenty of marriages do not last. Every married couple in the room is quietly sure that theirs will.
False Consensus Effect · Hindsight Bias · Optimism Bias
Open for the answer Optimism Bias. Each couple accepts the general odds but exempts themselves. Believing that bad outcomes are less likely for you than for comparable people is optimism bias. Read the entry →
32 Jamal says he is "ninety-nine per cent sure" of all ten of his pub quiz answers. He gets six right.
Hindsight Bias · Overconfidence Effect · Self-Serving Bias
Open for the answer Overconfidence Effect. His certainty ran well ahead of his accuracy. Confidence outrunning accuracy is the overconfidence effect; this is the form called overestimation, thinking you did better than you did. Read the entry →
33 Mia's holiday was mostly rainy and dull, with one spectacular boat trip midweek and a wonderful last dinner. Years later she remembers it as one of her best trips.
Hindsight Bias · Mere Exposure Effect · Peak-End Rule
Open for the answer Peak-End Rule. Her memory is built from the best moment and the ending, while the long dull stretch barely counts. That is the peak-end rule. Read the entry →
34 In the shower, Theo feels he is right on the edge of solving a problem that has bothered him all week. Then the feeling fades, with no answer.
Apophenia · Jamais Vu · Presque Vu
Open for the answer Presque Vu. The sense of being about to grasp something that never quite arrives is presque vu, literally "almost seen". Read the entry →
35 Asked an actor's name, Rosa knows it starts with B and has three syllables, but the name itself will not come.
Jamais Vu · Semantic Satiation · Tip-of-the-Tongue Phenomenon
Open for the answer Tip-of-the-Tongue Phenomenon. She has partial access, the first letter and the length, while the word stays out of reach. That is the tip-of-the-tongue phenomenon. Read the entry →
36 After interviewing six candidates in one day, the panel find they remember the first candidate's answers best of all.
Halo Effect · Primacy Effect · Recency Bias
Open for the answer Primacy Effect. What comes first in a sequence tends to be remembered better and weighted more. That is the primacy effect. Read the entry →
37 A salesperson has an average eleven months and a superb twelfth. Her annual review is glowing.
Halo Effect · Primacy Effect · Recency Bias
Open for the answer Recency Bias. The latest month is crowding out the eleven before it. Giving recent information more weight than it deserves is recency bias. Read the entry →
38 When Leah's presentation goes well, it is because she prepared hard. When the next one flops, it is because the projector kept failing.
Fundamental Attribution Error · Hindsight Bias · Self-Serving Bias
Open for the answer Self-Serving Bias. Success is credited to her; failure is blamed on circumstances. That pattern is the self-serving bias. Read the entry →
39 Ivy spills coffee on her shirt before a meeting and spends the whole hour sure that everyone is staring at the stain. Afterwards, nobody remembers it.
Barnum Effect · Negativity Bias · Spotlight Effect
Open for the answer Spotlight Effect. People notice far less about us than we feel they do. Overestimating how much others notice your appearance or behaviour is the spotlight effect. Read the entry →
40 Ravi has stayed on the same energy tariff for six years, though a cheaper one from the same supplier takes two minutes to switch to.
Mere Exposure Effect · Status Quo Bias · Sunk Cost Fallacy
Open for the answer Status Quo Bias. Staying put feels like the safe default, even when a better option is easy to take. That preference for things as they are is status quo bias. Read the entry →
41 Two hours into a dull film at the cinema, Eli stays to the end because "I've paid for the ticket".
Endowment Effect · IKEA Effect · Sunk Cost Fallacy
Open for the answer Sunk Cost Fallacy. The money is spent whether he stays or not; only his evening is still his to save. Letting what you have already put in decide what you do next is the sunk cost fallacy. Read the entry →
42 A town council keeps funding a bridge project that is years late and over budget, because so much has already been spent on it.
Bandwagon Effect · Optimism Bias · Sunk Cost Fallacy
Open for the answer Sunk Cost Fallacy. The money already spent cannot be recovered either way. The question is only whether the rest is worth spending, and the sunk cost fallacy blurs that. Read the entry →
43 "They built things to last in those days," says Dan, admiring a three-hundred-year-old cottage. He gives no thought to all the old buildings that fell down long ago.
Hindsight Bias · Mere Exposure Effect · Survivorship Bias
Open for the answer Survivorship Bias. He sees only the buildings that survived and draws a conclusion about all of them. Judging from the survivors while the failures are invisible is survivorship bias. Read the entry →
44 A magazine profiles five people who left university and became millionaires, and concludes that dropping out is a smart move.
Availability Heuristic · Halo Effect · Survivorship Bias
Open for the answer Survivorship Bias. The many people who left and did not become rich are not in the article. Drawing lessons only from those who made it through is survivorship bias. Read the entry →
45 Freya notices her bus has been late on each of the three days she wore her green scarf, and starts to suspect the scarf.
Apophenia · Baader-Meinhof Phenomenon · Gambler's Fallacy
Open for the answer Apophenia. She is seeing a meaningful link between things that are unrelated. Perceiving patterns in coincidence is apophenia. Read the entry →
// How it worksRead the scene. Each is a small, ordinary moment: a price tag, a missed deadline, a coin toss. They are invented examples, written for this page.Pick the bias. Three options, and the two that are wrong are usually close relatives of the right one, because telling neighbours apart is most of the skill. Keys 1 to 3 answer.Read why. Every answer comes with the reason in a sentence or two and a link to the entry, which has the research, its limits and its sources.Go again. Each round deals ten scenes from 45, never the same bias twice in a round. Nothing is scored against you or saved.// Three worked examplesTwo hours into a dull film at the cinema, Eli stays to the end because "I've paid for the ticket".
Sunk Cost Fallacy .
"They built things to last in those days," says Dan, admiring a three-hundred-year-old cottage. He gives no thought to all the old buildings that fell down long ago.
Survivorship Bias .
Mia's holiday was mostly rainy and dull, with one spectacular boat trip midweek and a wonderful last dinner. Years later she remembers it as one of her best trips.
Peak-End Rule .
// The biases in the deckA cognitive bias is a predictable pattern in how people judge and decide, where a useful mental shortcut leads somewhere it shouldn't. The quiz draws on 35 of the dictionary's 38 entries on biases and the mind:
Not used as answers: Actor-Observer Bias , Hot Hand Fallacy and Zeigarnik Effect . Their entries report that the evidence for them is weak or disputed, so asking you to "spot" them would teach something shakier than it sounds.
Another game: Real or 404? , five words a day, some real and some forged.