Work on this program project will continue in the areas of social development, cognitive development, and perceptual development. The social development project consists primarily of observational studies of social behavior in peer groups focussing on friendship formation, group structures, social curiosity, and the relation between mother-child interaction and adaptation to the peer culture. Studies of cognitive development will focus on retrieval from semantic memory, memory for "real-world" events, especially the functions and elicitors of such memory capacities. Problem-solving, with respect to its ecology, will be studied and naturalistic studies of grammatical errors occurring in early development will be conducted. The manner in which information about spatial orientation is acquired and utilized by children and adults will also be examined. In perceptual development, the role of auditory and tactual feedback on speech production will be investigated, along with pictorial perception and developmental factors in the perception of melodies. Other perceptual research will examine the development of sensitivity to pictorial depth information in infants; visual evoked cortical potentials will be used in the assay of visual capacities in infants as well as older subjects.