Arnold Gesell

Arnold Lucius Gesell was among the first psychologists to establish quantitative measures of child development, based on his extensive observations of New Haven children, whom he filmed through oneway mirrors in the laboratory. Born 1880 in Alma, Wisconsin, a small town that still refers to him as the most famous graduate of Alma High School, Gesell in 1899 graduated with a bachelor’s degree from Steven  Point  Normal  School.  In  1906,  he  earned his PhD from Clark University, specializing in child development under his mentor G. Stanley Hall (1844–1924). After earning his PhD in psychology, Gesell worked briefly in an elementary school before taking up the post of assistant professor at Yale University in 1911. There he founded the Yale Clinic of Child Development. At the age of 30, Gesell decided to study medicine, and in 1915, he received his MD from Yale University.

Using his observational studies, Gesell established developmental norms from birth to adolescence. These scales were not measures of Intelligence Quotient (IQ); rather, they described behaviors in four areas: personal-social, neurological-motor, language development, and overall adaptive.

The primary aim of Gesell’s Developmental Assessment was to observe children’s overall behavior in order to compare their developmental level with their chronological age. These assessment scales were used to assess children’s school readiness and to identify abnormal patterns of development that might necessitate further investigation. Gesell was also influential in adoption issues. Gesell believed that adoption posed a risk or was inappropriate for some children. He therefore advocated the use of his scales to determine whether children were suitable for adoption and to match their abilities to the abilities of the prospective adoptive parents.

The basis for Gesell’s theory of child development is rooted in the principle that development is influenced by two factors, the environment and genes, and that although development unfolds in a fixed sequence, the rate of development varies. Hence, he believed that children can only be taught a skill once they are ready for it and that each child is a unique individual and so cannot be classified on the basis of chronological age alone; rather, children have to be examined in the context of their sociocultural background. Gesell was aware of, and often referred to, the fact that children’s development needs to be assessed by examining various sources, such as cultural or social influences and observations by teachers, as well as taking into account measurements carried out in his laboratory. Nevertheless, he was criticized for the fact that the norms that he established were based usually on white middle-class children from well-educated backgrounds. Additionally, Gesell’s use of the concept of “normality” was criticized. It was considered too imprecise in that children who performed below established norms were still “normal,” according to Gesell, but just slower in their development. He wrote and coauthored many books and chapters, which are still in use today.


  1. Gesell, A. (1930/1966). The first five years of life: A guide to the study of the preschool c London: Methuen.
  2. Gesell, (1954).  The  ontogenesis  of  infant  behavior.  In L. Carmichael (Ed.), Manual of child psychology. New York: Wiley.
  3. Gesell Institute,