Cognitive biases are tendencies to think in certain ways that can lead to systematic deviations from a “standard of rationality” or good judgment, and are often studied in psychology and behavioral economics.

A cognitive bias is a pattern of deviation in judgment, whereby inferences about other people and situations may be drawn in an illogical fashion. Individuals create their own “subjective social reality” from their perception of the input. An individual’s construction of social reality, not the objective input, may dictate their behaviour in the social world. Thus, cognitive biases may sometimes lead to perceptual distortion, inaccurate judgment, illogical interpretation, or what is broadly called irrationality.

Some cognitive biases are presumably adaptive. Cognitive biases may lead to more effective actions in a given context. Furthermore, cognitive biases enable faster decisions when timeliness is more valuable than accuracy, as illustrated in heuristics. Other cognitive biases are a “by-product” of human processing limitations, resulting from a lack of appropriate mental mechanisms (bounded rationality), or simply from a limited capacity for information processing.

Cognitive biases are important to study because “systematic errors” highlight the “psychological processes that underlie perception and judgement” (Tversky & Kahneman,1999, p. 582). Moreover, Kahneman and Tversky (1996) argue cognitive biases have efficient practical implications for areas including clinical judgment.