Undertaken at orphanages in Russia, this study tests the role of early social and emotion experience in the development of children. Children were exposed to either multiple caregivers who performed routine duties in a perfunctory manner with minimal interaction or fewer caregivers who were trained to engage in warm, responsive, and developmentally appropriate interactions during routine care. Engaged and responsive caregivers were associated with substantial improvements in child development and these findings provide a rationale for making similar improvements in other institutions, programs, and organizations.