Overview
A cognitive bias is a systematic pattern of deviation from rational judgment or objective standards. People affected by a cognitive bias make decisions or draw conclusions that differ from those an unbiased, logical analysis would produce. Biases are central to the study of cognitive psychology and decision science because they reveal predictable limits of human reasoning. For a general primer, see further overview.
Causes and characteristics
Cognitive biases commonly result from simple mental shortcuts called heuristics, limited information-processing capacity, strong emotions, and social pressures. Some biases can be traced to adaptive responses shaped by evolution: fast rules of thumb helped our ancestors make rapid choices in uncertain environments, even though they can lead to errors in modern contexts. For discussions of evolutionary and cognitive roots, consult additional resources.
Common examples
- Confirmation bias — favoring information that supports existing beliefs.
- Availability heuristic — judging probability by how easily examples come to mind.
- Anchoring — relying too heavily on an initial piece of information when making estimates.
- Sunk-cost fallacy — continuing an endeavor because of past investments rather than future benefit.
- Optimism and hindsight biases — overestimating future success or perceiving past events as more predictable than they were.
History and research
Modern scientific interest in cognitive bias accelerated with research into heuristics and biases by scholars who demonstrated that human reasoning often diverges from formal models of probability and logic. The work inspired large literatures in psychology, behavioral economics, and neuroscience that map which biases occur, when they appear, and how cultural and contextual factors shape them. For scholarly surveys and experimental findings, see related literature.
Consequences and mitigation
Cognitive biases affect many domains: medical diagnosis, legal judgments, financial decisions, public policy, and everyday interpersonal choices. They can produce costly mistakes but also sometimes promote fast, satisficing decisions. Mitigation strategies include awareness training, structured decision processes (checklists, precommitment), statistical thinking, peer review, and methods from the scientific method such as randomized trials and replication to reduce the influence of systematic errors. Practical guides and tools can be found at applied resources.
Understanding cognitive bias helps explain predictable errors in human thought while offering paths to better decisions. Research continues to refine how biases interact, how they vary among individuals and cultures, and which interventions are most effective in particular settings.