Dynamics in Psychology: By Wolfgang Köhler. New York: Liveright Publishing Co., 1940. 158 pp.

For many years Köhler has been attempting to reconstruct upon the basis of experimentation in the psychological field, the physicochemical mechanisms in the central nervous system that are responsible for psychological phenomena. His method is a very straightforward one. He studies the dynamic properties of the psychological phenomena and assumes that the physicochemical processes underlying them must have similar dynamic properties. Making use of what is known about the physicochemical properties of central nervous tissues, he next searches about for a physicochemical system whose dynamic properties correspond to those suggested by the psychodynamic relationships. Such a system will undoubtedly possess also other dynamic properties. He then returns to psychological experimentation in order to determine whether the psychological relationships correspond to those of the hypothetical system. This method was already outlined by Köhler many years ago in a study entitled Die physischen Gestalten in Ruhe und im stationären Zustand; eine naturphilosophische Untersuchung (F. Vieweg & Sohn, Braunschweig, 1920) in which he pointed out in great detail the analogies between the field concept in physics and the new field or gestalt concept then being introduced into psychology. In the present work Köhler presents this thesis in English in a more or less popular form, drawing illustrations from experiments in the fields of visual perception and of retention and recall. He believes that the relations between figure and background that can be demonstrated by experiments on visual perception can be accounted for by the theory that an electrical current passes in one direction through the retinal areas corresponding to the figure