• Cross-sectional studies suggest that the intellectual development of American children is affected by experiences in the first three years of life. Furthermore, Piaget and White have observed and documented direct effects of the environment on the development of infants during the first year of life. Principles derived from animal research and the disappointing results of preschool intervention programs highlight the irreversible nature of early infant-environment interaction. Future programs designed to prevent educational incapacitation among children must concentrate on optimizing the developmental milieu of the child before he is 4 years old. Accomplishing this task is the practical challenge in the field of child development today.
(Am J Dis Child 130:410-415, 1976)