Cognitive Biases
Cognitive biases are systematic patterns of deviation from rational thinking. They affect how we perceive information, make decisions, and remember events — often without us even realising it.
Confirmation Bias
The tendency to search for, interpret, and recall information in a way that confirms what you already believe, while ignoring evidence to the contrary.
A person convinced that a particular diet is healthy only reads success stories and dismisses scientific studies showing no significant benefit.
Anchoring Bias
Relying too heavily on the first piece of information encountered (the "anchor") when making decisions, even when that anchor is arbitrary.
A car salesperson shows you a $50,000 model first. When you see a $35,000 car next, it feels like a bargain — even if it's still overpriced for what you need.
Availability Heuristic
Judging the likelihood of an event based on how easily examples come to mind, rather than on actual statistics.
After seeing weeks of news coverage about plane crashes, people become afraid of flying — even though statistically, driving to the airport is far more dangerous.
Dunning-Kruger Effect
People with limited knowledge in a domain tend to overestimate their competence, while true experts underestimate theirs because they're more aware of what they don't know.
A beginner who has played chess for two weeks is convinced they could beat most people. A grandmaster, meanwhile, can always name ten players stronger than themselves.
Sunk Cost Fallacy
Continuing to invest time, money, or effort into something because of what you've already put in — even when cutting your losses would be the rational choice.
You're an hour into a terrible movie but stay until the end because you already paid for the ticket, even though leaving would free up your evening.
Bandwagon Effect
Adopting beliefs or behaviours simply because many other people hold or exhibit them, regardless of independent evidence.
During a market frenzy, investors pile into a hot stock not because they've analysed the company, but because everyone else seems to be buying it.
Halo Effect
Allowing one positive (or negative) trait to colour your overall impression of a person, product, or idea.
A hiring manager unconsciously assumes an attractive, well-dressed candidate is also more competent and trustworthy than equally qualified peers.
Recency Bias
Placing more weight on recent events than on older ones, even when the older data is more representative of the long-term picture.
After a stock market correction, an investor sells everything and moves to cash, ignoring decades of historical data showing markets recover over time.
Survivorship Bias
Focusing on the people or things that "survived" a selection process while overlooking those that didn't, leading to false conclusions about success.
We hear inspiring stories about college dropouts who founded billion-dollar companies, but rarely about the thousands of dropouts whose ventures failed — making dropping out seem more viable than it is.
In-group Bias
The tendency to favour members of one's own group over outsiders, often without conscious awareness.
A hiring manager gives a slight edge to a candidate who attended their own university, interpreting their shared background as a sign of compatibility and competence.
Framing Effect
Drawing different conclusions from the same information depending on how it is presented — as a gain or a loss, positively or negatively.
People rate a surgical procedure as more acceptable when told it has a "90% survival rate" than when told it has a "10% mortality rate" — even though both statements are identical.
Negativity Bias
Giving more weight to negative experiences, information, or feedback than to equally significant positive ones.
A restaurant receives 50 glowing reviews and one scathing complaint. The owner fixates on the complaint for days, despite overwhelming positive feedback.