Psychology is an academic and applied discipline involving the scientific study of mental processes and behavior. Psychology also refers to the application of such knowledge to various spheres of human activity, including relating to individuals’ daily lives and the treatment of mental illness.

Psychology differs from the other social sciences — anthropology, economics, political science, and sociology — in that psychology seeks to explain the mental processes and behavior of individuals. Whereas biology and neuroscience study the biological or neural processes and how they relate to the mental effects they subjectively produce, psychology is primarily concerned with the interaction of mental processes and behavior on a systemic level. The subfield of neuropsychology studies the actual neural processes while biological psychology studies the biological bases of behavior and mental states.