As the first introductory statement of the ‘new psychology’, Motives and Mechanisms, originally published in 1985, aims to bring the study of human action to the forefront of the subject. Like any science, the practice of psychology is very much influenced by the hidden assumptions of its practitioners. The argument put forward in this important text shows how these assumptions can be brought out by comparing psychology with the natural sciences and with common-sense understanding. In pursuing the integration of traditional research methods with a new style of investigation, the basic principle is that social structures and mental structures are in reciprocal relation with one another because each is involved in the creation of the other. By adopting this principle social structures become the basis for research into the cognitive and emotional organization of mind. The authors devote two key chapters to the central question that underlies this stance: are human actions and human actors’ products of internal processes, such as those described by Freud, or of external social forces, of the kind described by Mead?