A psychologist is a person who studies normal and abnormal mental states, perceptual, cognitive, emotional, and social processes and behavior by experimenting with, and observing, interpreting, and recording how individuals relate to one another and to their environments. Psychologists usually acquire a four-year university degree, often with post-graduate work required. Unlike psychiatrists, psychologists usually cannot prescribe medication to patients. Psychologists can work with a range of institutions and people, such as schools, prisons, in a private clinic, in a workplace, or with a sports team.