Equation

B=ƒ(P,E)

Here is a psychological equation of behavior developed by Kurt Lewin which states that behaviour is a function of the person and their environment. The equation was first presented in Lewin's book Principles of Topological Psychology, published in 1936, and it contradicted most popular theories giving importance to a person's momentary situation in understanding his or her behaviour, rather than relying entirely on the past.