PREFACE AND ACKNOWLEDGEMENTS.

In 1967 the U.S. Office of Education developed a network of laboratories devoted to the understanding of the development of young children from birth through 8 years of age. Originally designated as the National Laboratory in Early Childhood Education (NLECE), its purpose was to foster basic research that would contribute to our understanding of how best to educate the young child for optimal developmental outcome. A component of the resources was devoted to research during the infancy period, and in 1968 the Kansas-based Kansas Infant Research Laboratory, as part of the Kansas Center for Research in Early Childhood Education, became part of the NLECE. The studies reported in this paper were, in large part, supported by the Office of Education through the NLECE program that eventually became the National Program in Early Childhood Education administered by the Central Midwestern Regional Education Laboratories. More recently the funding source has been shifted to the newly organized U.S. National Institute of Education.