As psychological methods contracted in number and experimentation became a dominant mode of inquiry, a number of systematic models of psychology were being produced. In addition to what was being termed the structural (content of mental events) and functional (mental processes) perspectives, psychologists counted among their intellectual schools Gestalt psychology, psychoanalysis, holistic psychology, dynamic psychology, and behaviorism. Some of the schools had few adherents and a short life. Freudian psychoanalysis, for instance, was quickly rejected as unscientific as well as being overly attentive to unconscious processes and sexuality. Gestalt psychology, with its emphasis on the metaphysics of immediate mental experience (and not behavior), lack of exact measurements, and roots in German psychology, never quite found a home in the United States.
Given this diversity of systematic models, historians often refer to the time between the two world wars as the period of “schools and systems.” Whether or not certain schools were even viable candidates for acceptance, it appears that in the decade following World War I psychologists staged their last substantive disputes over the nature of their discipline. These disputes often consisted of arguments about subject matter, notably whether behavior or consciousness was the proper object of study. So loaded was the ultimate outcome that these debates spawned a frequently cited witticism that first psychology gave up soul, then mind, and now would surrender its consciousness (but at least it would have some behaviors). Through these debates psychologists moved toward a consensus about psychology’s status as a science and its practical utility in society. However, they also displayed a crisis in confidence—an uneasiness about their accomplishments, promises, and potential. Some historians have viewed these internal self-doubts as side effects of the controversies over schools and systems. To many psychologists working in that period, however, such professional disequilibrium was symptomatic of a larger problem: the social and psychological infirmities of psychologists themselves. They suspected that the very stuff they observed and measured in their subjects—imperfect behaviors, irrational actions, and emotional expressions— also was manifested in conflicts and disunity among researchers, errors in research, and preoccupation with metaphysics. Such admissions of the cognitive shortcomings of the psychologist ultimately underscored the absolute necessity of the experimental method. The controlled and deductive method of experimentation would force rational and logical thinking and yield uncontaminated objective knowledge. Experimental research replaced the outmoded notion of human reason. Clark Hull’s (1884-1952) articulation of the hypothetico-deductive method and a factory-like organization of research cemented faith in experimentation. In the end, this methods-based resolution of psychologists’ postwar uncertainties eliminated many of the contesting theory schools. The tremendous faith in experimentation, combined with positivist beliefs in the study of observables and the commitment to a practical science, tilted the contest heavily in favor of behaviorism, a theory commitment that would dominate research until the 1970s.