Project Summary/Abstract The caregiving environment constitutes one of the most significant sources of early life experience for children. Early interactions with caregivers provide essential inputs that shape the developing brain and lay the foundation for children’s future social, emotional, and intellectual functioning. While an extensive body of work highlights the quality of early caregiver-child interactions (including caregiver sensitivity and responsiveness) as a key contributor to child health and development, emerging evidence suggests that the predictability of these interactions may also play a powerful role in shaping child development, especially within socioemotional domains. The strongest evidence for this claim comes from rodent models, which increasingly associate unpredictable maternal behavior with pervasive socioemotional impairments in rodent pups, and these impairments appear dependent on alterations in neural circuitry governing cognitive and emotional function (i.e., prefrontal-hippocampal-amygdala circuits). Recent behavioral evidence from human research also supports associations between unpredictable maternal behavior and impaired socioemotional functioning in children, including elevated risk for externalizing problems and reduced prosociality. However, the mechanisms underlying these associations are not well-understood in children. The proposed studies will integrate insights from animal and human models to directly address this gap in the literature and test potential neurodevelopmental and cognitive mechanisms linking unpredictable maternal care and the emergence of socioemotional problems in young children. Aim 1 will use existing longitudinal data from an investigation of children followed from birth to age 3 to test whether alterations in resting brain function, namely EEG band power and coherence in regions supporting executive function and social behavior, underlie the associations between unpredictable maternal behavior and children’s risk for subsequent externalizing problems. Aim 2 will involve an experimental test of whether deficits in neural and behavioral markers of executive function also contribute to associations between unpredictable maternal behavior and both externalizing problems and reduced prosociality in 4- to 5-year-old children. Together, findings will provide new insight into mechanisms linking unpredictable early caregiver inputs and socioemotional problems and may provide critical new direction to prevention and intervention efforts aimed at promoting healthy socioemotional development in children. This award will provide the candidate, who has a strong background in developmental psychology, with training in neurobiology and the use of EEG and ERP methods that will facilitate her transition into an independent research career.