Contributions

Founder of social psychology, jewish, born near my hometown in Poland (Poznan) in then Prussia.
Lewin also proposed Herbert Blumer's interactionist perspective of 1937 as an alternative to the nature versus nurture debate. Lewin suggested that neither nature (inborn tendencies) nor nurture (how experiences in life shape individuals) alone can account for individuals' behavior and personalities, but rather that both nature and nurture interact to shape each person. This idea was presented in the form of Lewin's equation for behavior, B = ƒ(P, E), which means that behavior (B) is a function (f) of personal characteristics (P), and environmental characteristics (E). [1]
Founder of action research [2]
There is nothing so practical as a good theory. - 'Field Theory in Social Science' - Kurt Lewin
Lewin also showed experimentally that people are more easily changed by being given the facts and allowed to decide for themselves than by unilateral persuasion. Alfred Marrow, a student of Lewin and owner of the Harwood Manufacturing Company, demonstrated experimentally that changes in production methods were

much more effectively introduced by joint decision-making than by mere consultation

Kurt Lewin