for irrationality as it relates to numbers, see rational number

Irrationality is talking or acting without regard of rationality. Usually pejorative, the term is used to describe emotion-driven thinking and actions which are, or appear to be, less useful than the rational alternatives. There is a clear tendency to view our own thoughts, words, and actions as rational and to see those who disagree as irrational.

Types of behavior which are often described as irrational include:

• fads and fashions
• crowd behavior
• unrealistic expectations
• belief in logical fallacies
• falling victim to confidence tricks
• belief in the supernatural without evidence
• stock-market bubbles

Why does irrational behavior occur?

The study of irrational behavior is of interest in fields such as psychology, cognitive science, economics and game theory, as well as of practical interest to the practitioners of advertising and propaganda.

Theories of irrational behavior include:

• people's actual interests differ from what they believe to be their interests
• mechanisms that have evolved to give optimal behavior in normal conditions lead to irrational behavior in abnormal conditions
• people's interests are controlled by emotional mechanisms, and "rationality" as such is a meaningless concept
• apparently irrational decisions are actually optimal, but made unconsciously on the basis of "hidden" interests that are not known to the conscious mind

See also

• behavioral economics

References

• Stuart Sutherland , N. S. Sutherland. Irrationality: Why We Don't Think Straight. ISBN 0813521505

External links

• Craig R. M. McKenzie. Rational models as theories – not standards – of behavior. TRENDS in Cognitive Sciences Vol.7 No.9 September 2003