PROJECT SUMMARY Cultural processes within the family influence behavior and cognition among all human groups and are theorized to be important for children's socioemotional development. The extent to which children subscribe to their family's values and practices (family orientation) is a cultural process that could have significant implications for children's development. Although these values are found to be important for Hispanic/Latinx and Asian American families, they have also been identified across racial/ethnic groups, suggesting the tremendous heterogeneity that exists both between and within groups. Self-regulation is a salient aspect of children's socioemotional functioning and is predictive of multiple positive outcomes throughout the lifespan, including academic achievement and social competence. It is imperative to elucidate processes that can bolster children's self-regulation. It has been theorized that cultural variation within the family shapes children's self-regulatory competence in early childhood, yet less is known about how these processes shape development in middle childhood. Twin study designs have a unique potential to elucidate these processes, demonstrating the role of additive genes and the nonshared environment in explaining differences in self- regulatory behaviors. However, many twin studies have neglected the role of cultural processes that could influence those estimates. Using a large, demographically diverse sample of twins in middle childhood, this NRSA fellowship proposes the development of novel measures of family orientation, to examine the relation between family orientation and self-regulation, and test whether family orientation influences the genetic and environmental contributions to self-regulation. My training objectives are to 1) obtain a deeper conceptual understanding of the role of cultural processes within the family in the development of children's self-regulation, 2) receive training in behavioral coding techniques, 3) obtain advanced quantitative training, and 4) receive additional professional development and ethics training. Developing novel measures of culture within the family affords researchers the opportunity to identify particular contexts that promote children's self-regulatory behaviors which can be targeted in prevention and intervention to enhance self-regulation and well-being.