The Mere Exposure Effect: Why Familiarity Breeds Preference
The research on the mere exposure effect, why we prefer things we have seen before, how it shapes preferences in work, relationships, and markets,...
April 2026
Mental Models for Better Decision Making
A practical guide to essential mental models - first principles, inversion, second-order thinking, Occam's razor - and how to apply them to make...
March 2026
The Curse of Knowledge: Why Smart People Explain Things Poorly
Curse of knowledge: experts forget what it's like not to know, making explanations unclear. Learn to overcome this bias and communicate effectively.
Framing Effects: How Presentation Changes Meaning
Framing effects show how the same information presented differently creates different reactions.
Why Most Decisions Fail Due to Poor Framing
Poor decision framing means asking the wrong question. 'Should I quit?' differs from 'What career maximizes growth?' Frame determines outcomes.
July 2025
Real Examples of Cognitive Bias in Action
Cognitive biases: Theranos investors showed confirmation bias ignoring red flags. Concorde project demonstrated sunk cost fallacy continuing...
June 2025
How Biases Are Formed
Pattern recognition overgeneralizes from few examples to broad rules. Cultural learning transmits biases. Emotions attach value creating preferences.
January 2025
System Justification Theory: Why the Disadvantaged Defend Harmful Systems
Women rate male job candidates more favorably than identical female candidates. Working-class voters oppose redistribution more strongly than the...
Prospect Theory: Why Framing Changes How Outcomes Feel
Tversky and Kahneman's 1981 Asian Disease Problem: 72% of subjects chose certain survival of 200 people over a gamble for all 600.
Mental Accounting: Why a Dollar Is Not Always a Dollar
You have two $100 bills in your wallet: one earmarked for rent, one for entertainment. You spend the entertainment $100 on dinner.
Implicit Bias: The Prejudice We Don't Know We Have
In 1998, Anthony Greenwald, Debbie McGhee, and Jordan Schwartz published the Implicit Association Test — a measure of automatic mental associations...
Cognitive Dissonance Reduction: Four Ways We Make Uncomfortable Truths Fade
A smoker who knows smoking causes cancer has a problem: the belief 'I smoke' conflicts with the belief 'smoking kills.' The discomfort of that...
Anchoring and Adjustment: Why the First Number Shapes Every Number After
Tversky and Kahneman spun a rigged wheel that landed on either 10 or 65, then asked subjects how many African countries are in the United Nations.
December 2024
Psychological Reactance: Why Bans Backfire
In 1975, Stephen Worchel put two cookies in one jar and ten in another, then told subjects the scarce jar was limited due to demand.
What Is the Planning Fallacy and Why Projects Always Run
The planning fallacy is the tendency to underestimate how long projects will take despite knowing that similar projects ran over. Learn the science, the inside view trap, and reference class forecasting.
Attribution Theory: How We Explain Why Things Happen — and Why We Get It Wrong
In 1967, Jones and Harris had subjects read essays supporting Fidel Castro's Cuba. Even when subjects were explicitly told the writers had been...
The Mere Exposure Effect: Why Familiarity Breeds Liking
In 1968, Robert Zajonc exposed subjects to nonsense words, Chinese characters, and photographs of faces at varying frequencies.
The Just-World Hypothesis: Why We Blame Victims and Call It Justice
In 1965, Melvin Lerner showed subjects an innocent woman receiving electric shocks. Unable to stop the shocks, observers began to derogate her —...
The False Consensus Effect: Why Everyone Thinks Their Views Are Normal
In 1977, Lee Ross asked Stanford students whether they would walk around campus wearing a sandwich board reading 'Eat at Joe's.' Those who agreed...
What Is the Spotlight Effect
The spotlight effect is the cognitive bias causing us to overestimate how much others notice and judge us. The Gilovich research, the illusion of transparency, and what it means for everyday life.
What Is Cognitive Bias: How Your Brain Misleads You
Cognitive biases are systematic errors in thinking that cause people to make irrational judgments, often without realizing it, affecting decisions...
The Self-Serving Bias: Taking Credit, Avoiding Blame
In 1964, Johnson, Feigenbaum, and Weiby gave teachers feedback on a student's performance. When the student improved, teachers attributed it to...
Moral Licensing: Why Doing Good Gives People Permission to Be Bad
In 2001, Benoît Monin and Dale Miller at Stanford showed that subjects who had the opportunity to establish moral credentials — by disagreeing...
The Curse of Knowledge: Why Expertise Makes You a Worse Communicator
In 1990, Elizabeth Newton asked Stanford students to tap out well-known songs and predict how many listeners would identify them.
The Bandwagon Effect: Why People Follow the Crowd
In 1951, Solomon Asch put subjects in a room with confederates who gave obviously wrong answers to a line-length judgment.
Illusory Correlation: How the Mind Manufactures Patterns That Do Not Exist
In 1967, Loren Chapman showed clinical psychologists Draw-a-Person test responses and patient diagnoses.
Hindsight Bias Explained
Hindsight bias is the tendency to believe after an event that you predicted it all along. Learn the psychology, research, and real-world consequences.
The Representativeness Heuristic: Why We Judge by Resemblance and Pay the Price
Linda is 31, outspoken, a philosophy major, passionate about social justice. Is she more likely to be a bank teller, or a bank teller active in the...
The Negativity Bias: Why Bad Is Stronger Than Good
John Gottman's lab found that marriages headed for divorce had a ratio of positive to negative interactions of about 0.8:1.
What Is the Status Quo Bias
Status quo bias is our tendency to prefer the current state of affairs over change. Learn about Samuelson and Zeckhauser's research, loss aversion, and how to overcome it.
November 2024
Choice Overload: When More Options Produce Fewer Decisions
At Draeger's grocery store in 1995, a display of 24 jams attracted 60% of passing shoppers. A display of 6 jams attracted 40%.
The Endowment Effect: Why We Overvalue What We Own
In 1990, Kahneman, Knetsch and Thaler randomly gave Cornell students a coffee mug. Sellers demanded a median $7.12 to give it up.
The Overconfidence Effect: Why the Smartest People Are Often the Most Wrong
In 1998, Long-Term Capital Management — run by two Nobel laureates and a team of PhDs — lost $4.6 billion in under four months.
The Tribe Within the Mind: Understanding In-Group Bias
In 1971, Henri Tajfel assigned Bristol schoolboys to groups based on a coin flip. Within minutes, they were systematically favoring their own...
The Framing Effect: Why the Same Fact Can Produce Opposite Decisions
In Kahneman and Tversky's 1981 experiment, 72% of people chose the option that saved 200 lives.
What Is the Recency Bias: How Recent Events Distort Judgment
Recency bias causes people to overweight recent events in their judgments and decisions. Learn the psychology, investing implications, and how to counteract it.
The Optimism Bias: Why the Human Brain Is Wired to Expect the Best
In 1957, the Sydney Opera House was estimated at £3.5 million, to be completed by 1963. Final cost: AUD $102 million. Completed: 1973.
The Gambler's Fallacy: Why the Mind Insists the Universe Keeps Score
On August 18, 1913, a Monte Carlo roulette wheel hit black 26 consecutive times. Gamblers lost millions betting on red, certain it was 'due.' The...
The Halo Effect
In 1920, Edward Thorndike noticed that military officers who rated their soldiers as intelligent also rated them as physically fit, loyal, and dependable — and vice versa. The ratings correlated far more strongly than the actual traits could possibly justify. Thorndike had identified the halo effect: a single positive impression radiates outward and distorts every subsequent judgment. A century later, research shows the halo follows us into hiring, justice, medicine, and every relationship we form.
The Anchoring Bias: How the First Number You Hear Colonizes Your Mind
In 1974, Kahneman and Tversky spun a rigged wheel in front of subjects — who knew it was rigged — and it still bent their estimates.
The Fundamental Attribution Error
In 1967, Edward Jones and Victor Harris asked students to rate the true attitudes of essayists who had written pro-Castro arguments. When told the writer chose the position freely, students inferred pro-Castro attitudes. When told the writer was assigned the position — forced to argue a side they might not believe — students still inferred pro-Castro attitudes. The situational constraint made no difference. The fundamental attribution error: we systematically underestimate the power of situations and overestimate the role of character when explaining other people's behavior.
The Sunk Cost Fallacy
In 1965, Britain privately knew Concorde would never turn a profit. The development costs were already sunk. The project continued for another decade. The sunk cost fallacy: why we continue failing projects, relationships, and wars because of what we have already spent — and why stopping feels like waste even when continuing creates far more of it.
Confirmation Bias: Why We Find What We're Looking For
In 1960, Peter Wason showed subjects the sequence 2-4-6 and told them it followed a rule. To discover the rule, they proposed triples. Almost universally, subjects proposed triples that fit their hypothesis — 4-6-8, 10-12-14 — and almost never proposed triples that could disprove it. The rule was simply 'any ascending sequence.' Confirmation bias: the systematic tendency to search for, favor, and remember information that confirms what we already believe.
Loss Aversion: Why Losing $100 Hurts More Than Winning $150
Kahneman and Tversky's 1979 prospect theory established that losses loom roughly 2 to 2.5 times larger than equivalent gains in subjective weight. Most people refuse a coin flip where they win $150 if heads and lose $100 if tails — despite a positive expected value. Loss aversion shapes housing markets, sports decisions, financial portfolios, and why we stay in bad situations far longer than rational calculation would predict.
Regression to the Mean: The Statistical Force That Rewrites History
Israeli Air Force flight instructors were certain punishment worked better than praise — every time they praised a good flight, the next was worse.
The Availability Heuristic
Tversky and Kahneman asked subjects whether more English words begin with the letter K or have K as their third letter. Most said K-first — wrong by a factor of three. Words starting with K are just easier to retrieve. The availability heuristic: we judge probability and frequency by how easily examples come to mind, not by how common they actually are. The science behind risk misperception, media effects, and why we fear the wrong things.
The Dunning-Kruger Effect: Why Incompetence Feels Like Expertise
McArthur Wheeler robbed two banks in broad daylight wearing no disguise — he had rubbed lemon juice on his face and believed it made him invisible...
The Map Is Not the Territory: Why Models Always Lie
Alfred Korzybski's principle: every model is an abstraction that omits, simplifies, and distorts. Long-Term Capital Management.
October 2024
The Dunning-Kruger Effect
In 1995, McArthur Wheeler robbed two Pittsburgh banks in broad daylight without a disguise. When police showed him surveillance footage, he was genuinely baffled. He had rubbed lemon juice on his face, believing it would make him invisible to cameras. This story prompted David Dunning and Justin Kruger's 1999 study: people with limited knowledge systematically overestimate their competence — because the skills needed to recognize incompetence are the same skills needed to perform competently.
Hanlon's Razor: Never Attribute to Malice What Stupidity
On September 26, 1983, Soviet Lt. Col. Stanislav Petrov watched five US missiles appear on his early warning screen. He chose not to retaliate — reasoning that a real attack would involve hundreds, not five. The system had a bug. Hanlon's Razor: why reaching for incompetence before malice is one of the most consequential intellectual disciplines a person can develop.
February 2024
Why Conspiracy Theories Spread: The Psychology of Mistrust and Pattern-Finding
Why do people believe conspiracy theories? Understand the cognitive, social, and motivational psychology that makes conspiracy thinking appealing,...
December 2023
Hofstadter's Law: Why Everything Always Takes Longer Than Expected
Hofstadter's Law states it always takes longer than you expect, even when you take into account Hofstadter's Law.
How to Think More Critically: The Science and Practice of Better Reasoning
What cognitive science, forecasting research, and epistemic psychology reveal about why reasoning fails and how to actually improve it.
Why Smart People Make Bad Financial Decisions: The Psychology of Money
Smart people make terrible financial decisions all the time. Behavioral economics explains the cognitive biases — loss aversion, present bias,...
November 2023
Decision Journaling: How to Systematically Improve Your Judgment Over Time
Decision journaling is the practice of recording your reasoning at the time of a decision and reviewing outcomes later.
September 2023
The Dunning-Kruger Effect Explained
The Dunning-Kruger effect describes how incompetence impairs the ability to recognise incompetence.
August 2023
The Planning Fallacy: Why Projects Always Take Longer Than Expected
Daniel Kahneman was part of a team writing a psychology curriculum. They predicted it would take 2 years.
May 2023
Hanlon's Razor: Never Attribute to Malice What Stupidity Can Explain
On September 26, 1983, Soviet Lt. Col. Stanislav Petrov watched five US missiles appear on his early warning screen.
December 2022
What Is Narrative Fallacy: How Stories Mislead Us
The narrative fallacy, coined by Nassim Taleb, explains why humans impose causal stories on random events.
What Is the Dunning-Kruger Effect: What the Research Actually Shows
The Dunning-Kruger effect explained: the original 1999 research, the replication debates, what it actually claims vs the meme version, and what it...
What Is Confirmation Bias and How It Affects Your Decisions
Confirmation bias explained: the Wason selection task, why it evolved, how it shapes politics, investing, and science, and proven strategies to...
What Is the Availability Heuristic: How Recent Events Skew Thinking
The availability heuristic makes us judge probability by how easily examples come to mind. Learn how it distorts risk perception and how to...
November 2022
The Sunk Cost Fallacy: Why Past Investment Makes Us Double Down on Bad Decisions
Britain and France had signed a treaty to build the Concorde supersonic jet in 1962. By 1968 it was clear the aircraft would never be commercially...
October 2022
What Is Price Anchoring: How the First Number Changes Everything
Price anchoring is the cognitive bias where the first number you see shapes all subsequent judgments of value.
Baader-Meinhof Phenomenon: The Frequency Illusion Explained
The Baader-Meinhof phenomenon makes you suddenly see something everywhere after first noticing it.
Survivorship Bias: The Hidden Graveyard of Failed Evidence
In 1943, military analysts studied bullet holes on returning bombers to decide where to add armor.
What Is the Status Quo Bias: Why We Prefer What Already Exists
Status quo bias is our tendency to prefer the current state of affairs over change. Learn about Samuelson and Zeckhauser's research, loss...
What Is the Spotlight Effect: Why People Notice You Less Than You Think
The spotlight effect is the cognitive bias causing us to overestimate how much others notice and judge us.
September 2022
What Is Exponential Growth and Why Our Brains Struggle With It
Exponential growth compounds on itself, doubling repeatedly. Learn why humans instinctively think linearly, how the chessboard problem illustrates...
What Is the Availability Bias in Investing
The availability bias causes investors to overweight recent dramatic events. Learn how it distorts portfolio decisions and how to counteract it...
The Spotlight Effect: Why You Think Everyone Notices You
The spotlight effect makes you feel observed and judged more than you are. Learn how social anxiety amplifies it and how CBT can help you see more...
August 2022
What Is the Fluency Effect: Why Easy to Read Feels True
The fluency effect means our brains mistake ease of processing for truth. Learn how font, rhyme, and clarity shape what we believe and how to...
What Is the Availability Cascade: How Repeated Claims Become Accepted Truth
The availability cascade explains how repeated media coverage turns unverified claims into perceived facts.
July 2022
What Is the Curse of Knowledge: Why Experts Struggle to Explain Things
The curse of knowledge explains why experts fail to communicate clearly. Learn how it affects teaching, writing, and leadership — and how to...
What Is the Availability Heuristic in Healthcare Decisions
The availability heuristic distorts healthcare decisions for patients and doctors alike. Learn how fear of rare diseases drives over-testing and...
What Is Retrospective Sensemaking: How We Rewrite Our Own History
How humans construct coherent narratives from ambiguous experience after the fact — and why this matters for learning, memory, and decision-making.
What Is the Default Effect: Why Pre-Selected Options Win
The default effect shows that pre-selected options are chosen far more often than alternatives.
May 2022
Loss Aversion: Why Losing $100 Hurts More Than Winning $150 Feels Good
Kahneman and Tversky's 1979 prospect theory established that losses loom roughly 2 to 2.5 times larger than equivalent gains in subjective weight.
April 2022
The Halo Effect: How One Good Quality Makes Everything Else Look Better
In 1920, Edward Thorndike noticed that military officers who rated their soldiers as intelligent also rated them as physically fit, loyal, and...
March 2022
The Fundamental Attribution Error: Judging Others vs. Ourselves
In 1967, Edward Jones and Victor Harris asked students to rate the true attitudes of essayists who had written pro-Castro arguments.