During the last 20 years, the mathematical formalism of quantum theory, especially so-called quantum probability, has found an increasing number of applications within the social sciences, in particular in psychology, economics, sociology, etc. This field, which is sometimes referred to as 'quantum cognition', is not about models or theories which assume quantum effects to be relevant for cognitive processes; the main underlying assumption of quantum cognition is rather that the formalism of quantum theory can be applied to various cognitive phenomena.
This article emphasizes the similarities between phenomena in quantum theory and phenomena in psychology and sociology, thereby presenting arguments why the formalism developed in quantum theory may be of relevance to the cognitive sciences. It is also intended to be a very cursory introduction to the ideas of quantum theory.