The primary focus of this grant is to evaluate the mutual regulatory processes (i.e., synchrony, affect sharing or matching, reparation from uncoordinated to coordinated affective states, bi-directionality, and maternal regulatory responsiveness) that take place between healthy mothers at low socio-medical risk and their 2 percent -year-old children. Data for 70 mother-child pairs (34 boys and 36 girls) have been collected. Therefore the purpose of this application is to request funding to code and analyze the available data. The data collected are a self-funded extension of a larger and completed study of infant socio-emotional development funded by NIMH (ROl MH45547, E. Tronick, PI) in which infants and mothers were assessed in the Face-to-Face Still-Face paradigm at 6 months and in the Strange Situation at 12 months. Using our own funds, we have continued to follow these dyads longitudinally at 2 1/2 years postpartum. At the 2 percent year visit, the mother-child dyads were videotaped during three interactive contexts that highlight mutual and self-regulatory processes in the mother-child interaction: child-caregiver problem solving, free play with the mother, and a preschool still-face perturbation during which the mother was instructed not to interact, talk, smile or touch the child. The primary purposes of the study are to: 1] describe the characteristics of mutual regulation between mothers and their male and female preschool children; 2] evaluate how mutual regulation processes between mothers and preschoolers (male and female) are related to psychosocial and demographic factors (e.g., child behavioral competencies and difficulties, child temperament, maternal psychological adaptation, and maternal social support); 3] assess the children's coping with the stress of the preschool still-face; and, 4] evaluate the stability of mutual regulation patterns over time from 6 months to 2 1A years and whether security of attachment is related to mutual regulation at 2 1/2 years. These issues have not received much attention in the research literature and will significantly increase our understanding of the mother-child relationship and child development.