Why memorizing cognitive biases isn't useless
A common objection: "knowing cognitive biases won't prevent me from experiencing them." This is partially true — knowledge alone doesn't immunize against biases. But it produces other useful effects: it allows you to recognize biases in others (which helps better analyze arguments), identify them retrospectively in your own decisions (and learn from them), and design decision-making devices that take them into account.
People who know cognitive biases well are generally better interlocutors in complex discussions, better analysts of uncertain situations, and better decision-makers in high-pressure contexts. It's a cross-cutting intellectual skill.
The ideal card format for cognitive biases
A cognitive bias deserves a three-part card:
- The definition: short and precise (2-3 lines maximum)
- A concrete example: drawn from daily life, business, or a social psychology experiment
- The associated trap: in which situation this bias is most likely to affect you
Exemple de carte pour le biais d'ancrage : Face : "What is the anchoring bias?" — Verso : "Tendency to give excessive weight to the first information received in a decision. Example: in a negotiation, the first price mentioned influences all subsequent offers. Trap: always check if your estimate was influenced by an arbitrary initial piece of information."
The 20 most useful cognitive biases to memorize
Reasoning biases
Confirmation bias: tendency to seek and retain information that confirms our existing beliefs, while ignoring that which contradicts them. One of the most studied and widespread biases.
Dunning-Kruger effect: people with low competence in a domain overestimate their skills; highly competent people underestimate them.
Anchoring bias: see above.
Availability bias (availability heuristic): we estimate the probability of an event based on how easily an example comes to mind. Plane crashes seem more frequent than car accidents because they get more media coverage.
Social biases
Halo effect: a positive (or negative) impression on one aspect of a person influences our evaluation of their other aspects.
Fundamental attribution error: tendency to explain others' behavior by their personality traits rather than circumstances, and the reverse for one's own behavior.
Groupthink: in a cohesive group, pressure toward conformity reduces critical thinking and questioning of decisions.
Authority bias: tendency to give more credit to opinions and decisions of people perceived as having authority.
Judgment and decision biases
Sunk cost fallacy: tendency to continue investing in something only because you've already invested in it, when the rational decision would be to stop.
Loss aversion: losses are perceived as twice as intense as equivalent gains (Kahneman & Tversky).
Status quo bias: preference for the current state of things — changes are perceived as potential losses.
Overconfidence: tendency to overestimate the accuracy of one's own judgments and predictions.
Social psychology experiments to memorize
In parallel with biases, memorize the major social psychology experiments that illustrate them. They give body to abstract concepts and are often more memorable than theoretical definitions.
The essentials: Milgram experiment (obedience to authority), Asch experiment (social conformity), Stanford experiment (effect of social roles), Kahneman & Tversky's work (systems 1 and 2, judgment biases under uncertainty). Card format: "[Name] experiment → protocol in one sentence + result + bias illustrated."
FAQ
How many cognitive biases exist?
Lists identify between 150 and 200 cognitive biases identified by cognitive psychology research. No need to memorize them all — most have redundant effects or very specific applications. Focus on the 30 to 50 most common and impactful biases in daily and professional decisions.
Does knowing biases make me more rational?
Not automatically. Studies on "debiasing" show that simple knowledge of a bias is insufficient to eliminate it — we continue to experience it even knowing it. What changes is the ability to detect it retrospectively, to design decision processes that take it into account (checklist, reflection delay, outside opinions), and to better analyze others' reasoning errors.