This project investigates endogenous and exogenous factors that contribute to the development of cognitive and social competencies in children during the first ten years of life. Before children are old enough to enter formal social learning situations, nearly all of their experiences stem directly from interactions they have with their primary caregivers. The project focuses on the extent to which several maternal characteristics (age, parenthood status, parity, employment status, as well as type of substitute care experienced during mother=s employment) influence observed relations between caregiving on the one hand and child developing cognitive and social competencies on the other. In this longitudinal approach, subjects are visited when they are 5 and 20 months and 4 and 10 years of age. At 5 months, mother-infant interaction is observed. At 20 months, measures of toddler functioning (play competence, language development, and social adaptation) and maternal behavior (play and intelligence) are obtained. At 4 and 10 years, diverse children=s abilities (representational competence, problem solving, reasoning skills, mathematical ability, language use and discourse, and selected aspects of generally adaptive behavior) are examined in detail and will be related to the earlier measures.