When defining the fields of Sociology, Anthropology and Psychology, it is clear that some mixing and melding of the fields occur. But there are definitive statements that describe the different areas of human life and existence that are distinctive to each field.
Anthropology involves the holistic study of human social construct, including all aspects of living life as a defined social group. Anthropologists develop understandings of previously unknown societies, or unobserved and unique aspects of known societies. The methods used in anthropology are different from those used in the other social sciences. Anthropologists traditionally live with and become fully immersed in the societies that they study in order to get a comprehensive and holistic understanding of all facets of social life. This is a mortal sin, according to practitioners of the more "hard" scientific methods, where the observer is not allowed to interact with, and therefore affect the subject, and where strict controls are placed on quantifying, objectivity, and the ability to replicate conditions of cause and effect. As a result, anthropology is the most valuable of the social sciences for gaining understanding of the new, the unknown, or the society that has not been closely enough observed in it's normal setting and ways of conduct. Much of the core knowledge that is used in the other social sciences is founded in the anthropological method of study and field research.
Psychology deals with the mind and how it functions in it's healthy form and in various forms of disorder. Psychology examines and tests intelligence and intellectual development in the individual, and how genetic, environmental and other factors affect intellectual development. Emotional, disease related, physical and other disorders of the mind are studied and examined.The arsenal of analytical, scientific and other tools of psychology range from anthropological approaches, to complex analytical models, to the classic approaches of hard science.
This field has grown in to a massive spread and mix with other natural and biological sciences. Some subsets, such as neurological psychology, have been split off into separate fields that incorporate medical science and technology with psychology. Psychologists can also serve as medical practitioners who apply diagnostic and therapeutic treatment to medical conditions that are defined as mental illness or disorder.
Sociology involves the study of societies as a whole, whether small groups or massive conglomerations of humanity. As with psychology, there are so many fields of sociology that the list would not fit into this article. The ways that societies are established, evolve, work, and change are studied. The social interactions between two people, or 6.6 billion people are studied. The effects of natural, human, technological and other factors on human group, societal and interpersonal structures are studied.
Sociological tools can range from those which are anthropological and psychological in nature, to highly complex analytical constructs. As with psychology, sociology can mix with any of the natural and other sciences in studying the massive complexity of human social construct, change, action and interaction. Sociologists can serve as planning and policy officials; survey, census and demographics experts; and as practitioners of various forms of social engineering for commercial and government policy, military strategy and intelligence, and in any scientific field where there is an impact on social systems or interactions.