Psychology is defined as the scientific study of the human mind and behavior. It includes understanding how humans and animals think, feel, and act. The document outlines the history of psychology from ancient Greek philosophers to modern approaches. It discusses major schools of thought like biological, behavioral, cognitive, and psychoanalytic perspectives. The branches and applications of psychology are also summarized, including areas like clinical, developmental, educational, and industrial psychology. Research focuses on topics like cognitive development, memory, and social/emotional development.