Leon Festinger was an American social psychologist who originated the theory of cognitive dissonance and social comparison theory. The rejection of the previously dominant behaviorist view of social psychology by demonstrating the inadequacy of stimulus-response conditioning accounts of human behavior is largely attributed to his theories and research. Festinger is also credited with advancing the use of laboratory experimentation in social psychology, although he simultaneously stressed the importance of studying real-life situations, a principle he practiced when personally infiltrating a doomsday cult. He is also known in social network theory for the proximity effect.

Social comparison theory, initially proposed by social psychologist Leon Festinger in 1954, centers on the belief that individuals drive to gain accurate self-evaluations. The theory explains how individuals evaluate their opinions and abilities by comparing themselves to others to reduce uncertainty in these domains and learn how to define the self. Comparing oneself to others socially is a form of measurement and self-assessment to identify where an individual stands according to their own set of standards and emotions about themselves.