Psychological research on populations had a tendency to replace the social categories that defined populations in real life with populations defined … - Kurt Danziger

Here we are more likely to come across fields that are structured in an agonistic manner, fields which are characterized by deep divisions between alternative schools of thought rather than by the achievement of a general working consensus.

The severe restrictions which Wundt placed on introspection also manifest themselves in the types of judgment that his experimental subjects were required to make. In accordance with the precept that internal perception can only become observation insofar as it is linked to controllable external stimuli, the introspective reports from his laboratory are very largely limited to judgments of size, intensity, and duration of physical stimuli, supplemented at times by judgments of their simultaneity and succession.

Internal perception also fails as a method for scientific psychology. In the nature of the case, it must be casual and therefore unsystematic. It excludes all deliberate investigation, because as soon as it becomes aware of itself it turns into the self-observation that is open to all the well-known and valid criticisms. It is, indeed, the basis of a psychology of consciousness, in the sense that conscious processes must be perceived to be known, but for a science it is not enough.