If we turn now from popular to scientific notions of psychology, we discern the following methods and aims of the science. There are two methods—(1) the introspective, by which one’s own mental states are observed; and (2) the objective, by which the conduct of others is observed: both may be studied without or under experimental conditions. It is very difficult to secure reliable introspection in backward peoples, and also to interpret the mental state of an individual by observing his behaviour.
The objects of psychology are five-fold:—
1. The study of mind compared with non-mental processes.
2. The study of the mind of the individual compared with other minds.
3. The study of the normal mind of the individual compared with the abnormal.
4. The study of the mind of one race compared with that of other races.
5. The study of the mind of genus Homo compared with that of animals.
All these are of interest and value for Anthropology, especially the second, fourth, and fifth.
In the earlier days of psychology, when the subject was in the leading-strings of philosophy, it had little ethnological value. Indeed, the possibility of such a subject as ethnological psychology was not realised.
Ethnical Psychology.