Interpersonal synchronization: Neural connections in the emotion system moderated by emotion regulation

Relationships are integral to personal development, providing the foundation for building strong emotional connections through shared experiences and mutual support. Emotion regulation (ER) plays a critical role in these processes, specifically interpersonal ER, which significantly influences how emotions are experienced and their physiological impacts. For instance, neural mechanisms like brain-to-brain synchronization facilitate social engagement and deeper connections through shared rhythmic responses during interactions. Synchronization involves aligning emotional states—including subjective experiences, behaviors, and physiological responses—which is essential for interpersonal emotion regulation. This process maintains the emotional balance and physiological homeostasis, reflecting both adaptive and maladaptive influences within relationships. This study explores how interpersonal ER affects friendship quality by examining the neural correlates of emotional connections and synchronization. Participants included friend dyads (N = 61) who engaged in questionnaires, emotional and neural measurements, and an interaction session. Our findings initially indicated no significant relationships between emotional and neural synchronization and overall friendship quality, suggesting these factors alone do not predict the strength of friendships. Similarly, no direct correlation was found between interpersonal ER and friendship quality. However, exploratory analyses identified significant relationships within specific friendship functions and interpersonal emotion regulation strategies. First, specific friendship functions (i.e., self-validation and emotional security) were notably influential for fostering positive neural connections while disclosing personal experiences. Additionally, emotional security was positively related to friends’ reliance on interpersonal ER strategies, and the function of seeking help was specifically associated with reliance on friends for perspective-taking. Furthermore, the use of social modeling was strongly linked to neural connections during these exchanges, suggesting friends who engage in social modeling experience increased synchronization. Together, our results revealed that interpersonal ER significantly enhances neural synchronization during emotional interactions. These findings highlight the complex interplay between interpersonal ER and synchronization mechanisms within friendships. Additionally, specific interpersonal dynamics are important in shaping emotional experiences, such as the functions of emotional security and help facilitate friends’ ability to regulate each other’s emotions. Our study demonstrates that reliance on friends for emotional support and regulatory strategies is crucial to friendships, reinforcing how interpersonal support enhances the depth of social connections.