Interpersonal emotion differentiation.

Emotion differentiation (ED), or the ability to make fine-grained distinctions about one's own emotional experiences, has been frequently linked to well-being but has only been studied as an intrapersonal construct. The present study proposes a new construct, Interpersonal ED, defined as the ability to classify others' emotions in a nuanced manner. Using daily diary data, we explored how Interpersonal ED is associated with ED, internalizing symptoms, and relationship satisfaction among 77 cohabiting couples. Participants self-reported their own emotions and their perceptions of their partner's emotions, which were used to calculate indices of positive and negative ED (NED/PED) and Interpersonal ED indices (Interpersonal NED/PED). Results show that although ED and Interpersonal ED were strongly associated, they were differentially related to internalizing symptoms. Specifically, greater NED (but not Interpersonal NED) was associated with participants experiencing greater anxiety symptoms in the context of heightened negative emotionality. In contrast, greater Interpersonal NED/PED (but not NED/PED) was associated with partners experiencing fewer anxiety symptoms, and Interpersonal NED alone was associated with partners experiencing fewer depressive symptoms. These findings highlight Interpersonal ED as a novel construct uniquely associated with mental health across individuals in romantic relationships. (PsycInfo Database Record (c) 2025 APA, all rights reserved).