This project focuses on long-term consequences of individual differences in physical, social, and affective functioning and the description of early interactions in diverse ecological contexts. In one study, we studied infant-mother interaction and attachment in infants from upper-middle class Euro-Americans and lower-class Central American families, developing culturally-sensitive criteria for evaluating normative social behavior and development. Regardless of social or ethnic background, mothers spent comparable amounts of time in discrete activities such as feeding, caring for, and playing with their infants. Systematic analyses demonstrated that the quality of social interaction within dyads changes dramatically depending on the functional and social context. As a result, extended observations are necessary to obtain reliable indices of individual differences. Comparable observations of mothers and infants in Costa Rica, Quebec, Germany, the Central African Republic, and Colombia are designed to further explore the effects of culture and context on early interactions.