Social psychology includes the study of interactions between individuals and groups, as well as the effects of groups on the attitudes, opinions, and behavior of individuals. The field covers such topics as persuasion, conformity, obedience to authority, stereotyping, prejudice, and decision making in social contexts. See also Motivation; Personality theory. Developmental psychology has three subfields: life-span development, child development, and aging. Most research in the area concentrates on child development, which examines the development of abilities, personality, social relations, and, essentially, every attribute and ability seen in adults. See also Aging; Intelligence.

Psychology differs from the other social sciences — anthropology, economics, political science, and sociology — in seeking to explain the mental processes and behavior of individuals. Psychology differs from biology and neuroscience in that it is primarily concerned with the interaction of mental processes and behavior on a systemic level, as opposed to studying the biological or neural processes themselves. In contrast, the subfield of neuropsychology studies the actual neural processes and how they relate to the mental effects they subjectively produce. Biological psychology is the scientific study of the biological bases of behavior and mental states.

History of Psychology:

Psychologists and others have exhibited a sustained interest in the history of the field since the rise of the "new" psychology. In his three-volume A History of Psychology (1912–1921), George Sidney Brett traced the philosophical background of modern psychological thought, from the ancient Greeks to his day. Edwin G. Boring, considering Brett's work too philosophical, was motivated to write A History of Experimental Psychology in 1929; Boring argued for the primacy of scientific research, saying "The application of the experimental method to the problem of mind is the great outstanding event in the history of the study of mind" (p. 659). Boring's book became the veritable Bible for courses in the history and systems of psychology. History was also used as a resource for asserting the unity of psychology despite the proliferation of diverse viewpoints.

After World War II, the history of psychology was pursued for two decades mostly as a teaching subject within psychology departments. In the mid-1960s the field became increasingly professionalized with new university programs starting and the APA founding a history division. A specialized journal, Journal of the History of the Behavioral Science (1965), and a society, Chiron: The International Society for the History of the Behavioral and Social Sciences (1969), provided support for scholars. In addition, professional historians, notably historians of science and medicine, grew more interested in and paid more attention to the history of psychology.