First published in English in 1968, Joseph Nuttin contributes the first chapter, on Motivation. He discusses various aspects of the motivational process. Such as incentives, conflict, social motivation, and negative motivation, and describes the mechanism of the process. The second chapter, by Paul Fraisse, is on the Emotions. Fraisse examines the nature of the emotions, both on the behavioural and on the neurophysiological levels, and goes on to define and discuss moving situations. He shows the different types of expression an emotional reaction may take, and discusses the causes of...

First published in English 1968, in this volume Paul Fraisse begins with history, looking at the evolution of experimental psychology, starting with its origins. He then moves on to the establishment of experimental psychology around the world. In the second chapter he discusses the experimental method. In the third chapter Jean Piaget tackles the questions of explanation and parallelism and their problems within experimental psychology. The final chapter by Maurice Reuchlin goes on to discuss measurement in psychology looking at various scales with their experimental conditions and numerical...