A neuropsychologist is a psychologist who specializes in the relationship between the human brain and human behavior. Not everything is known about how the brain functions, but doctors know that disorders within the brain and nervous system can cause changes in behavior and thinking. The job of a neuropsychologist is to study how the physical brain structures and systems relate to human behavior and cognitive abilities. Neuropsychologists are highly educated and have a doctorate in psychology. They also complete specialized training in neuropsychology. Most neuropsychologists work in research or in clinical offices.