The term “introspective psychology” is misleading in that it covers a variety of diverging positions on the theory and practice of introspection. From the beginning there was a basic discrepancy between the British and the German philosophic tradition, the former relying more exclusively on introspection than the latter. Wilhelm Wundt’s advocacy and use of introspection was extremely circumscribed and essentially limited to simple judgments tied to external stimulation. During the first decade of the twentieth century some experimental psychologists, notably E. B. Titchener and the , greatly enlarged the scope of introspection, ushering in the brief vogue of “systematic introspection.” The latter never gained wide support in North America and was supplanted in Germany by developments that do not constitute “introspective psychology” in any precise sense.

What exactly constitutes a field like scientific psychology? Is it constituted by its most innovative and influential contributors; by the scientific findings that it has produced; by the theories it has elaborated; by its concepts, techniques, or professional associations? Obviously, all this and more goes into the making of a field, but most of us would probably see some of these components as playing a more essential role than others. Even if we refuse to commit ourselves explicitly we are likely to imply that certain components define the field more effectively than others by the way we organize our knowledge.

Psychological research on populations had a tendency to replace the social categories that defined populations in real life with populations defined in terms of nonsocial categories. American psychology aimed to be a socially relevant science, but not a social science. Its approach was to be that of a natural science, although its ultimate field of application was to be found among members of real societies.

Wundt initiated the first systematic psychological research programme. This achievement occurred at the same time as his elaboration of a philosophy of science which was anti-inductivist and stressed the priority of explanatory motives. Specifically psychological explanations depended on concepts of psychological causality as manifested in apperceptive or volitional processes. The major differences between the Wundtian and other models of psychological experimentation can be understood in the light of this general approach. Thus experimenters and subjects had to be enlightened collaborators and the role of introspection was more significant in an explanatory than in a purely observational context. Wundt's special requirements for the psychological experiment led him to reject other early models as exemplified by the hypnotic experiment in which the experimenter-subject relationship was closer to what was to become the norm in the twentieth century.