Arnold Gesell broke new ground in his use of careful observation of children's behavior as a method of studying the orderly sequence of neuromotor development. Profoundly influenced by early embryologists who mapped the ontogeny of organ systems during fetal development, Gesell proposed that psychological development followed a similar orderly sequence governed by "lawful growth processes" (Gesell and Amatruda, p. 4). In his detailed studies of a small group of infants and young children, Gesell set out to define the stages of these orderly sequences and the laws governing their progression–what children are like at what point in their lives and how they respond to specific stimuli and test situations at different age levels.
Gesell's work was part of an emerging interest in defining normative patterns of physical and mental development that began in the mid-1800s with several so-called baby biographers who had chronicled events in their own children's lives. These personal histories of children's lives were a rudimentary beginning of a scientific approach to understanding normative patterns in children's psychological development. At Clark University, G. STANLEY HALL began to establish a database on the normal behavior and development of children as gathered through compilations of parent reports. His student, Arnold Gesell, took the field many steps further by defining observational methods for the quantitative study of human behavioral development from birth through adolescence. He pioneered the use of motion picture cameras and one-way screens to study the details of children's behavioral responses to specific situations and test materials, and his observations on the growth of behavioral organization provide maps of the stages of neuromotor maturation which researchers and clinicians studying infancy have relied upon ever since.
Gesell was born in 1880. He was among the first generation of American-born children born to German immigrants who had settled in Alma, Wisconsin. After receiving his bachelor's degree in 1906 from the University of Wisconsin, he obtained his Ph.D. in psychology from Clark University. Gesell accepted an assistant professorship at Yale in 1911. In his first years at Yale, he also worked toward his M.D., which he earned in 1915. Soon after his arrival at Yale, Gesell set up a "psycho-clinic" at the New Haven Dispensary, later known as the Clinic of Child Development, which he directed as Professor of Child Hygiene at Yale from 1930 to 1948. Gesell's clinic was the forerunner of the Child Study Center at the Yale School of Medicine.
Gesell's initial work focused on developmentally disabled children, but he believed that it was necessary to understand normal infant and child development in order to understand abnormality. He began his normative studies with infants and preschool children and later extended his work to children of five to ten and ten to sixteen. Gesell was one of the first to describe expectable maturational sequences in various domains of neuromotor development from early infancy through school age. He believed that, just as the body developed in genetically encoded, sequenced patterns, so behavioral patterns emerged in sequences reflective of differentiation in the central nervous system. In his own words:
A behavior pattern is simply a defined response of the neuro-motor systems to a specific situation… . Ayoung baby follows a dangled object with his eyes; eye following is a behavior pattern… . Behavior patterns are not whimsical or accidental by-products. They are the authentic end-products of a total developmental process which works with orderly sequence… . These patterns are symptoms. They areindicators of the maturity of the nervous system. (Gesell and Amatruda, p. 4)
He gave primacy to maturational processes and to endowment, a primary emphasis that has generated criticism from contemporary developmentalists. But he also believed that experience and environment played a major role in determining the rate of maturational change, and he (and all psychologists since) defined experience, the developmental environment, as beginning at conception.
Through his accumulated observations of the maturational sequences of various behaviors (detailed in An Atlas of Infant Behavior and The Embryology of Behavior), he created the Gesell Development Schedules, which are applicable for children between four weeks and six years of age. The instrument measures responses to test materials and situations both qualitatively and quantitatively. Areas assessed include motor and language development, adaptive behavior, and personal-social behavior; the child's performance is expressed as developmental age, which is then converted into a developmental quotient, representing the proportion of normative abilities for that individual child at his or her age. Gesell's work made it possible to apply standards for many aspects of development against which children may be compared to indicate how normally they are growing.
In the 1940s and 1950s, Gesell was regarded as a leading authority on child rearing and development, and his developmental schedules were widely used as a standard method for assessing children's developmental progress. He and his colleague, Francis L. Ilg, coauthored several books that are widely read by parents, including Infant and Child in the Culture of Today (1943), The Child from Five to Ten (1946), and Youth: The Years from Ten to Sixteen (1956), in which he applied his basic research and gave norms for behavior at successive stages of development. Although his original data were derived from what has been criticized as a small, unrepresentative sample, his efforts were nonetheless the first to base descriptions of children's normative development on systematically gathered, direct observations. Gesell's description of the invariant sequences of development, the growth principles, and the variability of rates of development are milestones in the history of developmental psychology.
Gesell, Arnold, and Catherine S. Amatruda. 1941. Developmental Diagnosis: Normal and Abnormal Child Development, Clinical Methods and Pediatric Applications. New York: Hoeber.
LINDA C. MAYES