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Lewin's equation

Lewin's equation, B = ƒ (P, E), s psychological equation of behavior developed by Lewin, states that behavior is a function of the person in their environment.

The equation is the psychologist's most well known formula in social psychology, of which Lewin was a modern pioneer. When first presented in Lewin's book Principles of Topological Psychology, published in 1936, it contradicted most popular theories in that it gave importance to a person's momentary situation in understanding his or her behavior, rather than relying entirely on the past.