Cognitive psychology refers to the study of human mental processes and their role in thinking, feeling, and behaving.
Developmental psychology is a scientific approach which aims to explain how children and adults change over time.
Abnormal psychology is a division of psychology that studies people who are "abnormal" or "atypical" compared to the members of a given society.
An approach is a perspective (i.e. view) that involves certain assumptions (i.e. beliefs) about human behavior: e.g behaviorism, humanism.
Social psychology looks at human behavior as influenced by other people and the social context in which this occurs.
A wide range of research methods are used in psychology, including experiments and case studies.