Arnold Lucius Gesell (21 June 1880 – 29 May 1961) was an American psychologist, pediatrician and professor at Yale University known for his research and contributions to the fields of child hygiene and child development. Early life Gesell was born in Alma, Wisconsin, and later wrote an article analyzing his experiences there entitled The Village of a Thousand Souls. The eldest of five children, Arnold and his siblings were born to photographer Gerhard Gesell and schoolteacher Christine Giesen. His first experience in observing child development involved watching his younger siblings learn and grow until he graduated from high school in 1896. After high school, Gesell attended the University of Wisconsin at Stevens Point, where a course taught by Edgar James Swift purportedly led Arnold to take an interest in psychology. Gesell worked as a high school teacher briefly before leaving to study at the University of Wisconsin–Madison. Later, he studied history under Professor Frederick Jackson Turner and psychology under Joseph Jastrow, receiving a bachelor of philosophy degree from Wisconsin in 1903. Career Gesell served as a teacher and high school principal before seeking his psychological doctorate at Clark University, where the university's president, G. Stanley Hall, had founded a child study movement. Arnold received his PhD from Clark in 1906. Gessell worked at several educational facilities in New York City and Wisconsin before obtaining a professorship at the Los Angeles State Normal School, now known as the University of California, Los Angeles. There he met fellow teacher Beatrice Chandler, who would become his wife. They later had a daughter and a son, Federal District Judge Gerhard Gesell. Gesell also spent time at schools for the mentally disabled, including the Vineland Training School in New Jersey. Having developed an interest in the causes and treatment of childhood disabilities, Gesell began studying at the University of Wisconsin Medical School to better understand physiology. He later served as an assistant professor at Yale University while continuing to study medicine. He developed the Clinic of Child Development there and received his MD in 1915. He was later given a full professorship at Yale. Gesell also served as the school psychologist for the Connecticut State Board of Education and helped develop classes to help children with disabilities succeed. This historic appointment made Gesell the first school psychologist in the United States. He wrote several books, including The Preschool Child from the Standpoint of Public Hygiene