Infant sleep, nighttime relationships, and attachment.

Much research, since the beginning of this century, has elucidated the sophisticated competencies of the human infant. It is now known that shortly after birth, the newborn is neither passive nor poorly organized as a participant in interaction. The infant is predisposed to actively engage the social and physical world, and to process novel information in a regular and predictable way. The infant is born with a propensity to choose (prefer) certain stimuli over others and is dependent upon actively participating in both biological and social regulation to maintain homeostasis (Stern 1985).