Psychology is the scientific study of human or other animal mental functions and behaviors. In this field, a professional practitioner or researcher is called a psychologist. Psychologists are classified as social or behavioral scientists. Psychological research can be considered either basic or applied. Psychologists attempt to understand the role of mental functions in individual and social behavior, while also exploring underlying physiological and neurological processes.

Basic research in psychology includes perception, cognition, attention, emotion, motivation, brain functioning, personality, behavior, and interpersonal relationships. Some, especially depth psychologists, also consider the unconscious mind. Psychologists employ empirical methods to determine causal and correlational relationships between psychosocial variables. In addition, or in opposition, to employing empirical and deductive methods, clinical psychologists sometimes rely upon symbolic interpretation and other inductive techniques.

While psychological knowledge is typically applied to the assessment and treatment of mental health problems, it is also applied to understanding and solving problems in many different spheres of human activity. The vast majority of psychologists are involved in clinical, counseling, and school positions, some are employed in the industrial and organizational setting, and other areas such as human development and aging, sports, health, the media, legal, and forensics. Psychology incorporates research from the social sciences, natural sciences, and humanities.