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Cognitive Biases: fun facts and quiz
The essentials in 7 ideas, with fun facts, an illustrated story and a quiz to see how much you know.
The essentials
Confirmation Bias
We tend to notice and remember what fits what we already believe, and brush off what doesn’t. That’s confirmation bias.
Key fact
Looking for evidence against your own idea is a good antidote.
Anchoring
The first number we see sticks, and pulls our guesses towards it. A “was £100, now £60” tag makes £60 feel cheap.
Key fact
Even random numbers can anchor people’s estimates.
The Availability Heuristic
We judge how likely something is by how easily examples come to mind. Plane crashes make the news, so flying feels riskier than driving, though it’s far safer.
Key fact
Vivid, recent events feel more common than they are.
The Bandwagon Effect
We’re more likely to do or believe something when lots of others do. Long queues and “bestseller” labels pull us in.
Key fact
In Asch’s 1950s tests, most people went along with a wrong group at least once.
The Sunk Cost Fallacy
We keep going with something because of what we’ve already put in, even when stopping would be smarter. Sitting through a bad film because you paid is a classic.
Key fact
Money already spent is gone either way. Decide on what’s ahead.
The Dunning–Kruger Effect
People with little skill in something often overrate how good they are, partly because they lack the know-how to spot their own mistakes.
Key fact
Highly skilled people sometimes underrate themselves instead.
Hindsight Bias
After something happens, we feel we “knew it all along”. Outcomes seem obvious once we know them, even when nobody predicted them.
Key fact
Writing predictions down beforehand keeps hindsight honest.
Fun facts
In a 1979 study, supporters and opponents of the death penalty read the same mixed evidence, and both grew more sure they were right.
In a classic study, people who saw a rigged wheel of fortune land on 65 guessed far higher than those who saw 10.
After 9/11, many Americans drove instead of flying, and road deaths rose.
The name comes from real bandwagons: in 1800s America, politicians rode wagons carrying bands to draw crowds.
It’s also called the Concorde fallacy, after governments kept funding the jet long after it clearly wouldn’t pay.
The study was inspired by a bank robber who thought lemon juice on his face would hide him from cameras.
People remember their past predictions as more accurate than they really were.
Story: I Knew It All Along
I Knew It All Along
1972. President Nixon is about to make historic trips to China and the Soviet Union. Psychologist Baruch Fischhoff asks students to predict how they’ll go.
Will Nixon meet Mao? Will the trip be called a success? The students give each outcome a chance, in writing.
After the trips, asked to recall their guesses, they remember having been surer about what actually happened. They’d “known it all along”.
True or false?
Tap your answer to see if you got it, and why.
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Question 1 of 10
Confirmation bias affects how we read evidence about our beliefs.
Show the answer
True. We give more weight to evidence that agrees with us.
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Question 2 of 10
A high first price can make later prices seem cheaper.
Show the answer
True. The first number becomes the yardstick.
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Question 3 of 10
Per kilometre travelled, flying is safer than driving.
Show the answer
True. Commercial flying is one of the safest ways to travel.
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Question 4 of 10
Seeing a long queue can make a restaurant seem better.
Show the answer
True. We take the crowd as a sign of quality.
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Question 5 of 10
What you’ve already spent should decide whether you carry on.
Show the answer
False. Past costs can’t be recovered. Only future costs and benefits matter.
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Question 6 of 10
Beginners often overestimate their skill.
Show the answer
True. Not knowing what you don’t know makes it hard to judge yourself.
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Question 7 of 10
Hindsight bias makes past events seem more predictable than they were.
Show the answer
True. Knowing the ending rewrites how obvious it felt.
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Question 8 of 10
Confirmation bias means people ignore every fact that disagrees with them.
Show the answer
False. It’s a tilt, not a wall: we notice less and weigh it less, but not zero.
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Question 9 of 10
Anchoring only affects people who are bad at maths.
Show the answer
False. It affects almost everyone, even experts like judges and estate agents.
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Question 10 of 10
Things we hear about often are always more common.
Show the answer
False. News covers the rare and dramatic, not the everyday.
Keep going in the app
KnowSoda learns what you know and brings back what you’re about to forget. Cognitive Biases has 6 more ideas at the Advanced and Expert levels.
Sources
- Tversky & Kahneman (1974), “Judgment under Uncertainty: Heuristics and Biases”, Science 185
- Kruger & Dunning (1999), “Unskilled and unaware of it”
- Asch (1956), studies of independence and conformity
- Florida Museum — International Shark Attack File
- WHO — World malaria report
- Tversky & Kahneman (1981), the framing of decisions, Science 211
- Pronin, Lin & Ross (2002), the bias blind spot, Personality and Social Psychology Bulletin 28
