Cognitive biases and logical fallacies: a list with examples

A cognitive bias is a predictable way our judgement goes wrong: we notice what confirms what we already think, we remember the vivid case over the common one, we keep going because we have already spent so much. A logical fallacy is a flaw in an argument: it can sound convincing while the reasoning does not hold.

Knowing their names helps, because a named trap is easier to spot, in other people’s arguments and in your own. Each one below links to its own page, with a short explanation and a story where it mattered.

Cognitive biases (43)

Anchoring: The first number we hear quietly steers every judgement that follows.
Availability Bias: What comes to mind easily feels likely, whether or not it is.
Backfire Effect: Facts thrown at a cherished belief can make people hold it tighter.
Bandwagon Effect: The more people do something, the more others join in, whatever the evidence.
Bias from Incentives: When pay or status depends on a conclusion, people tend to reach it, sincerely.
Blind Spot Bias: We see bias clearly in other people and hardly at all in ourselves.
Bystander Effect: The more people who see a problem, the less likely any one of them is to act.
Clustering Illusion: Randomness is lumpier than we expect, so we see patterns where there are none.
Cognitive Dissonance: When our actions and beliefs clash, we often change the story rather than the behaviour.
Commitment and Consistency Bias: Once we have said or done something, we bend later choices to stay consistent with it.
Confirmation Bias: We look for, notice and remember the evidence that agrees with what we already believe.
Deprival-Superreaction Tendency: Losing something we have, or almost have, provokes a reaction far bigger than gaining it would.
Disliking and Hating Tendency: Once we dislike someone or something, we stop judging it fairly.
Dunning-Kruger Effect: The less we know about something, the more likely we are to overrate our skill at it.
Envy and Jealousy Tendency: Seeing what others have can make us want things we never needed.
False Consensus Effect: We think far more people share our views and choices than really do.
First-Conclusion Bias: The first explanation that fits tends to become the only one we consider.
Framing: The same facts can lead to opposite choices, depending on how they are presented.
Fundamental Attribution Error: We blame people’s character for their behaviour and forget the situation pushing them.
Golem Effect: Low expectations can drag people down to meet them.
Grass is Greener Mentality: Other options look better from a distance than they turn out to be up close.
Halo Effect: One shining quality makes us rate everything else about a person or product higher.
Hindsight Bias: Once we know how things turned out, the outcome seems to have been obvious all along.
Horn Effect: One bad impression can cast a shadow over everything else we see in someone.
Just World Hypothesis: We like to believe that people get what they deserve, so we blame the unlucky.
Loss Aversion: A loss hurts more than an equal gain pleases, so we pay to avoid losses.
Narrative Instinct: We turn events into stories, and often see intention and meaning where there is only chance.
Non-Response Bias: The people who stay silent can change the answer as much as those who reply.
Observer-Expectancy Bias: We tend to see what we expect to see, and sometimes cause it without meaning to.
Optimism Bias: We expect things to turn out better, faster and cheaper than they usually do.
Out-Group Bias: We judge outsiders more harshly, and a simple team name is enough to start it.
Paradox of Choice: Some choice makes us free; too much choice makes us anxious and less satisfied.
Peak-end Rule: We remember an experience by its most intense moment and its ending, not by its length.
Publication Bias: The studies we read are often the lucky survivors of all the studies that were run.
Pygmalion Effect: High expectations can lift people up to meet them.
Response Bias: What people say about themselves often reflects how they want to appear, not what they do.
Scarcity: When something seems scarce, we want it more and think about little else.
Selection Bias: How you choose a sample can decide the answer before you ask a single question.
Self-Serving Bias: We take credit for our successes and blame our failures on everything else.
Semmelweis Reflex: We reflexively reject new evidence when accepting it would mean we were wrong.
Social Proof: When we are unsure what to do, we copy what other people are doing.
Survivorship Bias: When failures vanish from view, the survivors look like the whole story.
Tendency to Stereotype: We judge people by the group they seem to belong to, not by who they are.

Logical fallacies (25)

Ad Hominem: An argument does not become false because you dislike the person making it.
Appeal to Authority: A famous name or senior title is not evidence; ask how they know.
Appeal to Emotion: Strong feelings can carry an argument that the facts alone would never support.
Appeal to Ignorance: No evidence of harm is not evidence of no harm, unless someone has really looked.
Appeal to Pity: A sad story can stir real sympathy and still have nothing to do with the question.
Bandwagon Fallacy: How many people believe something tells you about its popularity, not its truth.
Base Rate Fallacy: A vivid detail means little until you know how common the outcome is in general.
Black and White Fallacy: Most real choices have more than the two options on offer.
Causal Fallacy: Two things happening together is not proof that one caused the other.
Circular Argument: A claim cannot be its own proof, however smoothly it is restated.
Conjunction Fallacy: Every added detail makes a story more convincing and less likely.
Equivocation: A statement can be technically true and still built to mislead.
False Dilemma: When a choice is framed as either-or, the best option is often the one nobody mentioned.
Gambler’s Fallacy: Chance keeps no score, so nothing is ever due.
Hasty Generalisation: A few examples, however vivid, are not enough to support a sweeping rule.
Hot-Hand Fallacy: A winning streak feels like momentum, but it is often luck on a good run.
Monte Carlo Fallacy: A roulette wheel has no memory, however long the streak.
Non Sequitur: True facts can still be strung together into a conclusion that does not follow.
Red Herring Fallacy: The most persuasive answer is sometimes an answer to a different question.
Regression Fallacy: Inventing a cause for a return to normal is one of the commonest mistakes we make.
Slippery Slope: A first step does not lead to disaster unless every link in the chain holds.
Strawman Fallacy: Beating a weaker version of someone’s argument proves nothing about the real one.
Sunk Cost Fallacy: What you have already spent is gone, so it should not decide what you do next.
Texas Sharpshooter Fallacy: Draw the target after the shots and every shooter looks like a marksman.
Tu Quoque: Pointing out that a critic does the same thing does not make the criticism wrong.

These are part of a larger set: all 365 mental models, sorted by the situation they help with.