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.

Susan C. Crockenberg is a Professor of Psychology at the University of Vermont. Her research focuses on the development of infants in families and other contexts, the mother-infant relationship, the role of temperament in development/psychopathology, and the development of emotion regulation in the first 3 years of life.

Michael Rutter is Professor of Developmental Psychopathology at the Institute of Psychiatry, King's College, London. His research interests span a wide field but particularly focus on the developmental interplay between nature and nurture and the use of natural experiments to test causal hypotheses about genetic and environmental mediation of risk in relation to normal and abnormal psychological development. He is the recipient of numerous international awards and honors and has published over 40 books and over 400 scientific papers.

Marian J. Bakermans-Kranenburg is Full Professor at Leiden University, the Netherlands. She has been involved in studies on disorganized attachment, attachment in children with autism, attachment-based interventions, and stress regulation. She contributed to several meta-analyses, including attachment-based interventions, the Attachment Q-Sort, secondary traumatization, attention bias, and physical growth in adopted children. Her recent work has addressed the effects of gene-environment interaction and children's differential susceptibility to childrearing influences.