Cognitive Bias and Heuristics

What it is

Cognitive biases are systematic patterns of deviation from rational judgment. They arise because the brain uses heuristics — mental shortcuts — that work well most of the time but produce predictable errors in specific situations.

Common biases include:

Confirmation bias. Favoring information that confirms existing beliefs.
Anchoring. Over-relying on the first piece of information encountered.
Availability heuristic. Judging probability by how easily examples come to mind.
Hindsight bias. Believing past events were predictable in retrospect.
Sunk cost fallacy. Continuing investment in a losing course because of past commitment.
Loss aversion. Weighting losses more heavily than equivalent gains.
Dunning-Kruger effect. Overestimating competence in domains where you're a novice.

Origin

The research program began with Amos Tversky and Daniel Kahneman in the late 1960s and 1970s. Their work showed that human judgment under uncertainty deviates systematically from probability theory — not as random noise, but in predictable directions. Kahneman won the 2002 Nobel Prize in Economics for this work, which became the foundation of behavioral economics.

Why this matters

Understanding biases helps in:

Decision-making. Recognizing when a shortcut is leading you astray.
Negotiation. Anchoring and framing effects shape outcomes more than the underlying facts.
Investing. Loss aversion and overconfidence drive predictable market behavior.
Communication. People process the same information differently depending on how it's framed.
Self-knowledge. Awareness of your own biases is the first step to compensating for them.

What this quiz measures

This site's cognitive bias quiz assesses your susceptibility to specific biases — not your IQ or general reasoning ability. A high score means you are more aware of common pitfalls; a low score is an opportunity to learn which biases tend to affect your thinking most.

Limitations

Knowing about a bias does not eliminate it. People who can name biases still fall for them.
Some "biases" reflect rational adaptation to specific environments — what looks like a bias in lab studies can be optimal in real-world contexts.
Replication of bias research has been mixed. Some classic findings (e.g., priming effects) have not replicated reliably.
This quiz captures self-aware susceptibility, which differs from actual susceptibility — self-report can be biased about bias.

Citations

Tversky, A., & Kahneman, D. (1974). Judgment under uncertainty: Heuristics and biases. Science, 185(4157), 1124–1131.
Kahneman, D. (2011). Thinking, Fast and Slow. Farrar, Straus and Giroux.
Gilovich, T., Griffin, D., & Kahneman, D. (Eds.). (2002). Heuristics and Biases: The Psychology of Intuitive Judgment. Cambridge University Press.
Gigerenzer, G., & Goldstein, D. G. (1996). Reasoning the fast and frugal way. Psychological Review, 103(4), 650–669.