Human Cheatcodes
A cognitive bias is not a mistake you make sometimes. It is a mistake you make the same way every time, without noticing, because your brain was built to decide fast with half the facts. Here are the twelve that do the most damage to ordinary decisions — money, work, relationships — each with an example you will recognise and a fix that does not depend on willpower.
1. Anchoring
What it is. The first number you hear sets the range for everything after it.
Everyday example. A jacket marked "was £180, now £90" feels like a bargain even if £90 is what it always cost. In a salary negotiation, whoever names a figure first has already won half the argument.
The fix. Decide your number before you hear theirs. Write it down. If they open first, treat their figure as information about them, not about the thing.
2. The sunk cost fallacy
What it is. Continuing something because of what you have already put in, rather than what you will get out.
Everyday example. Finishing a bad film because you have watched an hour of it. Staying in a degree, a job or a relationship because of the years invested — years that are gone either way.
The fix. Ask one question: "If I were starting from zero today, would I choose this?" The past cost is identical whether you stop or continue. Only the future is on the table.
3. Confirmation bias
What it is. Noticing, remembering and believing evidence that agrees with what you already think.
Everyday example. Deciding a colleague is lazy, then noticing every long lunch and none of the late nights. Reading three articles that agree with you and calling it research.
The fix. Before deciding, write one sentence: "The evidence that would change my mind is…" If you cannot finish the sentence, you are not weighing evidence. You are collecting ammunition.
4. Loss aversion
What it is. Losses hurt about twice as much as equivalent gains feel good.
Everyday example. Holding a falling investment rather than selling and "making the loss real." Keeping a gym membership you never use because cancelling feels like giving something up.
The fix. Reframe every hold as a purchase: "Would I buy this today at this price?" If not, you are only holding it to avoid the feeling.
5. The availability heuristic
What it is. Judging how likely something is by how easily an example comes to mind.
Everyday example. Fearing a plane crash after seeing one on the news while driving to the airport, which is the dangerous part of the journey. Believing crime is rising because you saw a video, when the figures say otherwise.
The fix. Ask for the base rate — the actual number out of a hundred — before trusting the vivid story. Vivid is not the same as frequent.
6. The halo effect
What it is. One good quality colours your judgement of everything else about a person.
Everyday example. Assuming the well-dressed, articulate candidate is also competent. Trusting an attractive stranger's directions more than a scruffy one's.
The fix. Rate the qualities that matter separately, in writing, before forming an overall impression. Interviews that score each competency independently are far better predictors than the "gut feel" that follows a good handshake.
7. The fundamental attribution error
What it is. Explaining other people's behaviour by their character and your own by your circumstances.
Everyday example. The driver who cuts you up is an idiot; when you cut someone up, you were late for something important. The colleague who missed the deadline is unreliable; when you missed one, the brief was unclear.
The fix. Before judging someone's character, ask what situation would make a reasonable person do that. Usually there is one.
8. Overconfidence
What it is. Being more certain than your track record justifies — and being most certain in the areas you know least.
Everyday example. Ninety per cent of drivers rate themselves above average. Beginners in any field feel expert after a weekend, and genuine experts hedge because they can see how much they do not know.
The fix. Keep score. Write down predictions with a confidence level and check them later. Nothing recalibrates confidence like a record of being wrong.
9. Hindsight bias
What it is. Once you know how something turned out, it feels as if you knew all along.
Everyday example. "I always said that company would fail." You did not. You said it might, alongside four other things that did not happen, and memory has quietly deleted the misses.
The fix. Decision journals. Write what you expect and why, at the time. Judging decisions by the outcome alone teaches you nothing, because good decisions sometimes end badly and bad ones sometimes get lucky.
10. The bandwagon effect
What it is. Believing something more because many people believe it.
Everyday example. Buying the product with ten thousand reviews without reading whether they are about the same version. Changing your view of a film after seeing its score.
The fix. Form your view first and check the crowd second. And remember that a crowd can be made of people who each assumed someone else had checked.
11. Status quo bias
What it is. Preferring things as they are, simply because that is how they are.
Everyday example. Staying with the same bank, insurer and energy supplier for a decade while paying more than a new customer would. Keeping the default settings on everything.
The fix. Put a date in the calendar to reconsider the defaults once a year, and treat "we've always done it this way" as a description, not a reason.
12. The planning fallacy
What it is. Underestimating how long things will take and how much they will cost, even when you know you did it last time.
Everyday example. Every kitchen renovation ever. Every "I'll have it done by Friday." The Sydney Opera House was scheduled for 1963 and opened in 1973.
The fix. Ignore your plan and look at how long similar things actually took for other people. Then add the difference. The outside view is almost always right and it almost always feels pessimistic.
Why knowing about them is not enough
Every one of these operates before you have had a chance to think, which is why reading a list of biases makes people feel wiser without making their decisions any better. The fix is never "be more aware." It is structure — a rule you set in advance, when you are calm, that runs whether or not the bias is firing:
Decide tomorrow. Almost every bias weakens overnight.
Base rate first. Write the boring number down before you hear the vivid story.
Name the evidence that would change your mind. Before you decide, not after.
Run a pre-mortem. Imagine it is a year later and the decision failed. Write the most likely reason. Then check whether you can fix that reason now.
SN1001 is the reference for exactly this — the patterns that run underneath your decisions and everyone else's, numbered so you can find the one you need in the moment. Chapter One is free and complete.
Read chapter one free →Common questions
What is a cognitive bias?
A consistent, predictable way the mind departs from accurate judgement — a shortcut that is usually useful but fails in the same direction every time. Biases are not stupidity; they are the price of a brain built to decide quickly.
What are the most common cognitive biases?
For everyday decisions: anchoring, the sunk cost fallacy, confirmation bias, loss aversion, the availability heuristic, the halo effect, the fundamental attribution error, overconfidence, hindsight bias, the bandwagon effect, status quo bias and the planning fallacy.
Can you overcome biases just by knowing about them?
Mostly not. What works is procedure: deciding tomorrow, writing down the base rate first, naming the evidence that would change your mind, and running a pre-mortem.
What is an everyday example of anchoring?
A jacket marked "was £180, now £90" feels like a bargain even at its ordinary price, because £180 anchored your sense of what it is worth.