The 1990s were designated by the American Psychological Association as the decade of the brain and intense research during the decade brought to fruition remarkable discoveries related to synaptogenesis, neural network formation, neurotransmitter action, bioregulation, and linkages between brain structure and function. From our perspective, equally remarkable findings to emerge from the decade of the brain involve the extent to which development of the brain and nervous system was found to be bound to the environments in which development takes place. Indeed, the synergy from such intensive studies spilled over into the public domain and, seemingly for the very first time, the general public began to realize that caregiving and education really were connected to brain development.
In many respects, the twentieth century could bear the title of “the century of the baby.” Never before in the history of the human species was there such a span of time in which so much attention was given to the first five years of human life. Early in the century, psychoanalytic theorists (Sigmund Freud, Erik Erikson), cognitive developmentalists (Jean Piaget), behaviorists (John Watson), and maturationists (Arnold Gesell) focused attention on the importance of the first three years of life for setting foundations for subsequent development. During the 1920s and 1930s, investigators began to establish major research laboratories to study the basic sensory, perceptual, motor, and learning abilities of infants and toddlers. Such investigations led to development of formal examinations that could be used to compare infants and toddlers against normative standards. A paradigmatic shift in Western psychology took place during the 1950s and 1960s, with the result that the tabula rasa infant became the competent infant.
Investigators, liberated from restrictive mechanistic models of behavior, enthusiastically embraced organismic theories and challenged infants as never before to reveal the secrets of their early postnatal development. The shift from mechanistic to organismic paradigms paved the way for the