No theory forbids me to say "Ah!" or "Ugh!", but it forbids me the bogus theorization of my "Ah!" and "Ugh!" - the value judgments. - Theodor Julius Geiger (1960)

Kurt Lewin

Kurt Lewin (1890-1947) was a Jewish-German psychologist who has had great influence on psychology and social psychology. Well-known scholars who worked with him, included Gordon Allport, Chris Argyris, Leon Festinger, Rensis Likert and Margaret Mead (Marrow, 1969).

The Practical Theorist

Before the 1920s, most psychologists were mainly concerned with laboratory experiments that consisted largely of collecting facts that were then further analyzed into their smaller components. As a result, researchers often approached complex behavioural problems with an oversimplified view of human behaviour (Marrow, 1969). Lewin was highly critical of this approach. Psychologists, he emphasized, should conduct their research within the framework of a theoretical system. Without theory it was not possible for any science to progress. Theory, Lewin argued, should serve two main functions: first, it should take into account what is known, and second, it should point the way to new knowledge. Experiments should therefore be undertaken to test theoretical concepts, rather than simply collecting and analyzing basic facts or statistically classifying behaviour. Kurt Lewin was a pioneer in the experimental testing of theoretical concepts. Lewin did a lot of these experiments already in the early days of his career, e.g. “The problem of measuring the will and the basic law of association” (Lewin, 1922).

Dynamic instead of static situations

If we see concepts as instruments for understanding the world, Lewin proposes, then we can contrast Aristotelian concepts with Galilean concepts. Whereas Aristotle was primarily concerned with classifying things into normative dichotomous categories, Lewin drew attention to the specificity of empirical situations, in all their dynamics. According to Lewin, describing what you observe outside is not enough; you need to have models to investigate, for example, dynamic problems of changing group life.

“The social scientist should be clear that he, too, needs intervening variables, and that these dynamic facts rather than the symptoms and appearances, are the important points of reference alike for him and for the social practitioner.” (Lewin, 1947)

Relations rather than just elements

Writing before Ludwig von Bertalanffy wrote about open systems, Lewin was already involved in studying emerging characteristics from a dynamic whole. Lewin was connected to Gestalt Psychology, which theorized systems with emerging properties, albeit often in different terms:

“In the social as in the physical field the structural properties of a dynamic whole are different from the structural properties of subparts. Both sets of properties have to be investigated. When one, and when the other, is important, depends upon the question to be answered. (…) For instance, it may be wrong to state that the blond women living in a town “exist as a group”, in the sense of being a dynamic whole which is characterized by a close interdependence of their members. They are merely a number of individuals who are “classified under one concept” according to the similarity of one of their properties. If, however, the blond members of a workshop are made an “artificial minority” and are discriminated against by their colleagues they may well become a group with specific structural properties. Structural properties are characterized by relations between parts rather than by the parts or elements themselves.” (Lewin, 1947)

Multi- or interdisciplinary science

Lewin argued for collaboration between various sciences:

“Some psychologists still view with suspicion the reality of those cultural facts with which the anthropologist is concerned. They tend to regard only individuals as real and they are not inclined to consider a “group atmosphere” as something, which is (…) let us say, a physical field of gravity. (…) The denial of existence of a group, or of certain aspects of group life, is based on arguments which grant existence only to units of a certain size, or which concern methodologic-technical problems, or conceptual problems.” (Lewin, 1947)

Field Theory

Lewin argued that human behaviour can only be understood or predicted when the psychological tensions in a "field" are understood (Lewin, 1936).

The needs, or the saturation of the needs, at a given moment determine what happens following a stimulus. Barriers in the field provoke a search for another way to reach the goal. After reaching the goal, the tension decreases, and equilibrium is reached. A need (physiological or a goal/intention) only exists when the inner balance is disturbed. A person's behaviour is derived from a totality of simultaneously existing facts, which are interdependent in a dynamic field. Lewin speaks of "life space" as the total psychological environment that the person experiences subjectively. It includes needs, goals, unconscious influences, memories, beliefs, political, social, and economic events, and anything else that can directly influence behaviour. This produces dynamic tension and forces. Behaviour depends most on the psychological present, although the past and (wishes for) the future also play some role. Behavior (B) is a function of the life space, in other words: a function of the person (p) and their cultural environment (e).


Lewin’s picture of Life Space and its environment (Lewin, 1936)

Change management according to Lewin: Reducing opposing forces

Lewin did a lot of action research, and he found out that people don't even try to achieve highly valued goals if they don't see a way to achieve them. Help is needed in the first step of an improvement. Reducing opposing forces is the most promising here, because an increase in tension above a certain limit is associated with greater fatigue, higher aggression, higher emotionality and lower constructiveness.

Lewin was in a sense the forerunner of Jens Rasmussen and his dynamic safety model (Rasmussen, 1997), as can be illustrated with quotes such as:

- “One of the forces keeping production down is the strain of hard or fast work. There is an upper ceiling for human activity. For many types of work the force away from the strain increases faster the closer one comes to the upper limit. The force field probably has a gradient similar to an exponential curve.” (Lewin, 1947)

- “The common belief views the desire to make more money as the most important force toward higher production levels. To counter the gradient of the forces away from that work, various incentive systems are used which offer higher rates of pay above a certain standard.” (Lewin, 1947); Lewin notes that an increase in earning a certain amount means quite different things to different people, and gives an example of some factories which moved from a northern state to a southern state couldn't meet the previous level of production, due to the weekly pay for "the southern girls" being so much above previous living standards, that they didn't care to make more money for even a small additional effort.


Kurt Lewin has taught to start any analysis not with the observable behaviour, but with the situation as a whole, the field (or “system”) and its environment. A constellation of mutually interdependent factors.


Lewin, K. (1922), Das Problem der Willensmessung und das Grundgesetz der Assoziation I & II, in: Psychological Research Vol. 2, Iss. 1.

Lewin, K., (transl. by Heider, F. & Heider, G.M.) (1936), Principles of topological psychology, New York: McGraw-Hill.

Lewin, K. (1947), Frontiers in Groups Dynamics: Concept, Method and Reality in Social Sciences, in: Human Relations 1:5.

Marrow, A.J. (1969), The Practical Theorist: The Life and Work of Kurt Lewin, New York: Basic Books.

Rasmussen, J. (1997), Risk management in a dynamic society: a modelling problem. in: Safety Science 1997; 27:183–213.