ABSTRACT
Arnold Lucius Gesell was a pioneer in developmental psychology when the field was in its infancy. As a physician and experimentalist, Gesell blazed a trail of discoveries about early motor, cognitive and emotional development that is unrivaled. Developmental psychologists have criticized Gesell for proposing a stage theory of infant growth that has fallen into disfavor among contemporary researchers. Gesell's dissertation "Jealousy" was published in the American Journal of Psychology, founded by Hall in 1887. Gesell gained notoriety at Yale for becoming the first school psychologist on the Connecticut Board of Education. Gesell reasoned that infants born at post-term may be further developed, but this is not due to added growth or precocity, as the infant is simply performing normally for its true age. His intention was to develop a set of criteria that would furnish a diagnosis of an infant's level of maturation with respect to age-based norms of adequate neurological, behavioral, and emotional function.
