This is a book that I read spontaneously and only in parts. The book is written in an accessible way; there is no difficulty in skipping sections.
What I took away: Kurt Lewin tries to overcome mechanistic and linear-causal thinking in psychology, using ideas from physics (force field) and mathematics. He starts from a life space, consisting of the person and his environment, which this person passes through and changes in the process. So the person acts and is influenced by the life space, like a compass needle by the magnetic field or an asteroid by the earth's gravitational field.
Lewin has a spatial conception of the life space. As an early example, Lewin describes the experience of a wartime landscape, where he perceived the front as the boundary of the landscape and where the state of war also changes the objects in the landscape, e.g. furniture, and their wartime character becomes visible, e.g. as fire wood or barricades.
The elements of life space, and this is a central concept of Lewin's, can have (attractive or repulsive) promptive character, i.e. valence (from valency and value). The occurrence of several valences at the same time can lead to conflicts for the person, such as
- the choice between two elements with positive valence
- the choice of the lesser evil between two elements with negative valences
- the approach/avoidance conflict in the case of elements that have both a positive and a negative valence
The life space as a field with attractive and repulsive forces is one of Lewin's objects of investigation. The readiness to act, the determining tendency of the person is the second field of investigation of Lewin and his students.
I found the connection to Gestalt psychology interesting. Christian von Ehrenfels generalised the idea of melody into a concept of gestalt, and named oversummativity -- a melody is more than the individual notes -- and transposability as characteristic properties. A drawing of a table is also a gestalt: more than the individual strokes and enlargeable. Lewin now transferred the Gestalt idea to actions and so dealt with unfinished / interrupted actions and substitute actions.
As I said, I have only read a little of the book, and I am leaving some of it out. I didn't find the transfer of topological concepts to psychological phenomena very interesting.
Since reading it, I walk through my life space with altered attentiveness and notice the valences around me. Trello has it, the sweets on the table have it. The subway coming in makes me stand up, even if it's the wrong line. Thinking in fields reminds me of Porter's 5 forces model and Eckhart Böhme's Wheel of Progress. The idea of actions as movement in the life space reminds me of the customer journey in design thinking.
For that alone, the book is an enrichment.