Multimodal Assessment and Longitudinal Trajectory of Callous-Unemotional Behaviors in Young Children: The Role of Parental Emotion Socialization - PROJECT SUMMARY Conduct problem (CP) symptoms in early childhood, including aggression and defiance, are associated with adverse social, emotional, and behavioral outcomes extending into adolescence and adulthood. The presence of callous-unemotional (CU) behaviors among children with CPs exacerbates these negative outcomes and reduces the effectiveness of evidence-based treatments. Given the severe negative trajectories and high societal costs associated with early CP and CU, it is important to accurately identify young children exhibiting CU behaviors to inform early intervention efforts for children with CPs. Traditional measures of CU behaviors exhibit some inconsistencies, necessitating a more nuanced multimodal approach. This study utilizes multiple units of analysis, including physiological measures (i.e., heart rate variability), parent/teacher ratings, and observational coding, to assess levels of CU among young children with and without CPs. Emotional development in early childhood, encompassing empathy acquisition, is shaped by direct interactions with parents and environmental observations. Parents play a crucial role in socializing their children's emotional experiences through supportive or non-supportive reactions, discussions, and emotional expressiveness. Parental emotion socialization, particularly emotion talk, is considered a crucial factor influencing child outcomes. Positive emotion socialization is linked to favorable outcomes, including less severe symptoms of CP and lower levels of CU behaviors, highlighting the importance of parental influence. While cross-sectional research establishes the impact of parental emotion socialization on child empathy and CP severity, the current study aims to investigate the longitudinal association (across the course of one year), specifically examining whether it can buffer the negative effects of CU on later CP severity. The study involves secondary data analysis from a sample of children with and without CPs (n=323), exploring multiple measures of CU behaviors across three timepoints. Aim 1 seeks to determine if physiological functioning, observed empathy, and parent/teacher ratings of CU behaviors converge into a single latent factor. Aim 2 will examine intra- and interindividual variability in the CU latent factor at baseline and over time, and its predictability of CP severity on year later. Lastly, Aim 3 focuses on parental emotion socialization and its potential impact on the link between CU behaviors and later CP severity.