Cognitive Bias Test

About this cognitive bias test

This cognitive bias test is a free, 15-question quiz that shows which common thinking shortcuts tend to influence your choices. A cognitive bias is a systematic error in judgment: a predictable way that fast, intuitive thinking drifts from careful reasoning. Each scenario below is built around one well-studied bias, from confirmation bias and anchoring to the sunk cost fallacy and optimism bias.

The quiz is an educational self-reflection exercise, not a validated psychological assessment. It draws on decades of research by psychologists such as Daniel Kahneman and Amos Tversky, but a single question per bias cannot measure a stable trait, and the scoring has not been tested for reliability. Use it to notice patterns and spark curiosity, then read the explanations further down the page.

• 15 everyday scenarios, one per bias
• About 3-5 minutes to complete
• Illustrative results showing which biases your answers leaned toward, with links to learn more
• Private: your answers are processed in your browser

Take the test

How the results work

Each question offers four answers, ranging from a careful, evidence-checking response to one that follows the typical pull of the bias. Your overall result is a percentage placed in one of four bands: highly reflective, generally balanced, often intuitive or strongly intuitive. You also see the biases where your answers leaned furthest toward the shortcut.

Read the result lightly. Most people answer hypothetical questions more carefully than they act in real life, partly because the quiz itself primes you to look for a trap. Researchers who study bias rely on controlled experiments, comparisons between groups and many trials, not single self-report items. A "highly reflective" score does not mean you are immune, and a "strongly intuitive" score says nothing about intelligence or mental health.

Understanding cognitive biases

What are cognitive biases?

Cognitive biases are systematic errors in thinking that occur when we process and interpret information. Many come from heuristics: mental rules of thumb that let us decide quickly with limited time and information. Heuristics usually work well enough, which is why we have them, but in certain situations they produce errors that lean in a predictable direction.

These biases are not character flaws or signs of low intelligence. They affect everyone, including experts in their fields. In their early work, Tversky and Kahneman showed that even trained researchers made predictable statistical errors when reasoning intuitively. Understanding these patterns is a foundation for stronger critical thinking and better decisions.

Cognitive bias is closely related to, but distinct from, cognitive dissonance, the mental discomfort we feel when our beliefs and actions conflict. That discomfort frequently drives biased thinking: to relieve the tension, we cling to evidence that confirms what we already believe and dismiss what challenges it. The study of these patterns sits at the heart of cognitive psychology and shaped the field of behavioral economics. For a broader catalogue, see our guide to cognitive biases.

Fast and slow thinking

A popular way to explain bias is the dual-process model that Kahneman described in Thinking, Fast and Slow (2011). "System 1" is fast, automatic and intuitive; "System 2" is slow, effortful and deliberate. Most biases appear when System 1 offers a quick answer and System 2 accepts it without checking. Kahneman presented the two systems as a useful metaphor rather than two separate parts of the brain, and researchers still debate how sharply the two modes can be separated.

The 15 biases in this test

1. Confirmation bias

Confirmation bias is the tendency to search for, interpret and remember information in ways that support what we already believe. In Raymond Nickerson's 1998 review it appears in settings from scientific research to courtrooms. Example: someone convinced a new diet works notices every success story and skims past studies showing no effect.

2. Anchoring bias

Anchoring is over-relying on the first number or piece of information we encounter. In a classic 1974 demonstration, Tversky and Kahneman had people spin a wheel that landed on 10 or 65, then estimate the percentage of African countries in the United Nations. Those who saw the higher number gave much higher estimates, even though the wheel was obviously irrelevant. Retail "was" prices and opening offers in negotiations work the same way.

3. Availability heuristic

The availability heuristic means judging how likely something is by how easily examples come to mind. Dramatic, recent or heavily reported events, such as plane crashes, feel more common than they are, while quieter risks like car travel are underestimated.

4. Dunning-Kruger effect

The Dunning-Kruger effect describes the finding, from Kruger and Dunning's 1999 studies, that people who scored lowest on tests of logic, grammar and humor tended to overestimate their performance the most, while top scorers slightly underestimated their relative standing. Later researchers have argued that part of the pattern is a statistical artifact (regression to the mean and the "better than average" effect), so the effect is real but often exaggerated in popular accounts.

5. Sunk cost fallacy

The sunk cost fallacy is continuing with a plan because of time, money or effort already spent, even when the future costs outweigh the future benefits. Hal Arkes and Catherine Blumer's 1985 studies showed people sticking with costly choices simply because of what they had already invested, such as attending a trip they no longer wanted because the ticket was non-refundable.

6. Bandwagon effect

The bandwagon effect is adopting beliefs or behaviors because many other people have. It overlaps with research on conformity, such as Solomon Asch's line-judgment studies (see the Asch conformity experiment) and the wider topic of social influence. Popularity can be a reasonable signal, but it is not evidence that something is true or right for you.

7. Hindsight bias

Hindsight bias, the "I knew it all along" effect, is believing after the fact that an outcome was more predictable than it really was. Baruch Fischhoff's 1975 experiments showed that once people learn an outcome, they overestimate how likely they would have judged it beforehand. It can make us unfair to past decision makers and overconfident about predicting the future.

8. Attribution bias

The quiz's attribution question targets the self-serving bias: crediting our successes to our own skill and blaming our failures on circumstances. A related pattern, the fundamental attribution error, is explaining other people's behavior by their character while underestimating the situation they were in.

9. Halo effect

The halo effect is letting one positive trait, such as attractiveness or confidence, color our judgment of unrelated qualities. Edward Thorndike named it in 1920 after noticing that military officers rated soldiers similarly across very different traits. It shows up in hiring, grading and brand perception.

10. Overconfidence bias

Overconfidence is overestimating the accuracy of our knowledge or our chances of success. In calibration studies, people who say they are "90% sure" are typically right far less often than 90% of the time. Overconfidence contributes to planning mistakes, risky investing and failure to seek a second opinion.

11. Framing effect

The framing effect is reaching different decisions from the same information depending on how it is presented. In Tversky and Kahneman's 1981 "disease problem," most participants chose a sure option when outcomes were described as lives saved, but most chose a gamble when the identical outcomes were described as lives lost. "90% survival" and "10% mortality" are logically the same but feel very different.

12. Recency bias

Recency bias is giving too much weight to the latest events. Investors may expect a recent market rise to continue, and managers may judge a whole year's work by the last few weeks.

13. Gambler's fallacy

The gambler's fallacy is believing that past random events change future odds, for example expecting "red is due" after a run of black on a roulette wheel. Each spin is independent. Tversky and Kahneman linked this to a belief in the "law of small numbers," the expectation that short sequences should look as balanced as long-run averages.

14. Status quo bias

Status quo bias is preferring things to stay as they are, even when a change would serve us better. William Samuelson and Richard Zeckhauser documented it in 1988, and it helps explain the power of default options, such as automatic enrolment in retirement plans.

15. Optimism bias

Optimism bias is believing we are less likely than other people to experience negative events, such as illness or divorce, and more likely to experience good ones. Neil Weinstein's 1980 research on "unrealistic optimism" was an early demonstration. Mild optimism can support motivation, but it can also lead people to skip precautions or underestimate how long tasks will take.

The research behind this test

The modern study of cognitive bias grew from the "heuristics and biases" program that Amos Tversky and Daniel Kahneman began in the early 1970s. Their 1974 paper in Science described three core heuristics (representativeness, availability, and anchoring and adjustment) and the systematic errors each one produces. Their later prospect theory explained why losses loom larger than equivalent gains. Kahneman received the 2002 Nobel Memorial Prize in Economic Sciences for this work; Tversky had died in 1996, and the prize is not awarded posthumously.

Other researchers added biases from social psychology (attribution errors, the halo effect, conformity) and from economics (status quo bias, the sunk cost effect). Not every finding has held up equally well. Large replication projects have generally reproduced classic anchoring and framing effects, while the size of some effects, including the Dunning-Kruger pattern, has been debated. Gerd Gigerenzer and colleagues have also argued that heuristics are often "ecologically rational," meaning they perform well in the real environments they evolved for, so calling them errors depends on the standard used.

The bias blind spot

One of the most consistent findings is that people see bias more easily in others than in themselves. Emily Pronin, Daniel Lin and Lee Ross named this the bias blind spot in 2002: participants rated themselves as less biased than the average person, even after learning about the biases in question. Part of the reason is that we judge ourselves by our intentions and introspection, which feel unbiased, but judge others by their behavior.

This matters for a quiz like this one. Knowing the "right" answer to a scenario is different from acting on it when you are tired, rushed or emotionally invested. A good use of your results is to pick one or two biases and watch for them in real decisions over the next few weeks.

How to reduce the impact of cognitive biases

Debiasing research suggests that simply knowing about a bias helps little, but changing how decisions are made can help. These techniques have research support or are widely used in fields such as medicine, aviation and forecasting:

1. Consider the opposite. Before deciding, list reasons your preferred view might be wrong. Lord, Lepper and Preston (1984) found this reduced biased evaluation of evidence more than simply asking people to be fair.
2. Start from base rates. Ask how often this kind of thing usually happens before focusing on vivid details. This counters availability and the base-rate fallacy.
3. Set your own anchor first. Write down an estimate or budget before seeing a price, offer or forecast.
4. Use checklists and structured criteria. Rating each quality separately limits the halo effect in interviews and assessments.
5. Get independent input. Ask others for their view before sharing yours, to avoid anchoring them and to reduce groupthink.
6. Keep a decision journal. Record what you predicted and why, then compare with outcomes. This exposes hindsight bias and overconfidence.
7. Run a "pre-mortem." Imagine the plan has failed a year from now and explain why. This tool, popularized by psychologist Gary Klein, counters optimism and planning errors.

Some structured training has shown measurable gains. In studies led by Carey Morewedge in 2015, a single session of instructional games or videos reduced several biases on later tests, with some benefit lasting weeks. Results like these suggest bias is partly a skill problem that practice can improve, not a fixed flaw.

Limits of this quiz

• It uses hypothetical scenarios, which are easier to answer carefully than real decisions made under pressure.
• Each bias is represented by a single question, so chance and wording have a large influence on your result.
• The answer options are ordered by how closely they match a typical bias pattern; this is a teaching device, not a scored psychometric scale.
• It has no norms, so it cannot tell you how you compare with other people.
• It does not measure intelligence, personality or mental health, and should not be used for hiring, grading or any other decision about a person.

If you want to go further, explore the individual bias guides linked above, read about Daniel Kahneman's work, or browse the psychology study guides for related topics in cognition and decision making.