The goal of this application is to develop a research program that, as stated in the call entitled The Neural Mechanisms of Multi-Dimensional Emotional and Social Representation (RFA-MH- 17-300), incorporates innovative approaches designed to move the fields of affective and social neuroscience beyond single region-based, modular, and static models of brain function and behavior. The RFA calls for research that is multi-dimensional, that is, that investigates the role of (among others) complex contexts, as well as distributed and/or dynamic processes that unfold over time. The objective of the present application is to jointly investigate emotional and social processes in a richly multi-dimensional manner. Aim 1: Network organization and evolution during emotional and social processing. The objective of this aim is to uncover how large-scale brain networks are organized and evolve temporally during emotional and social processing. Networks will include brain regions that robustly respond to the tasks proposed, and regions from well characterized networks, including the salience, executive control, and task-negative networks. Aim 2: Naturalistic processing during emotional and social processing. The objective of this aim is to understand naturalistic processing of emotional and social information. Although standard experimental designs afford great control over experimental conditions, they lack ecological validity and restrict the experiments that can be studied. We propose to investigate continuous (?naturalistic?) processing during movie watching involving emotional and social content. Continuous processing will be investigated via intersubject correlation analysis, which measures the extent to which signals are correlated across participants. Aim 3: Development of network organization/evolution and naturalistic processing. The objective of this aim is to investigate multi-dimensional emotional and social processes from a developmental perspective. Most developmental research in emotion has focused on observing amygdala responses and those of a few other brain regions during face perception. We focus on a question largely neglected in prior research, specifically sustained threat processing and the involvement of the bed nucleus of the stria terminalis. In the context of social processing, this aim examines the development of intersubject synchrony. Across the emotional and social domains, we propose to study middle childhood (8-9 y), early adolescence (12-13 y), and young adulthood (18-19 y).