Is the More the Merrier? Affective Outcomes of Emotion Polyregulation Depend on the Idiographic Effective Strategy Ratio Across Cultures.

UNLABELLED: Emotion polyregulation refers to the use of multiple emotion regulation strategies within an emotional episode. However, empirical findings regarding its affective outcomes remain inconclusive. This inconsistency likely arises from reliance on strategy count as a proxy for polyregulation, while neglecting that the effectiveness of discrete emotion regulation strategies differs by individuals and cultures. To resolve this inconsistency, across two ecological momentary assessment studies in the United States (N = 158; 12,217 observations) and China (N = 144; 11,347 observations), we introduced the idiographic effective strategy ratio, the ratio of idiographically effective strategies to total strategies used at a given moment, to characterize the idiographic quality. Across both samples, polyregulation showed opposite associations with momentary distress depending on idiographic quality: when the idiographic effective strategy ratio was low, polyregulation was associated with higher distress, whereas when the ratio was high, polyregulation was related to lower distress. These results held after controlling for lagged distress and in a temporal hold-out test segregating effective strategy identification and outcome prediction. Cultural differences emerged in the composition of idiographically effective strategies especially for engagement strategies, but not in implementing them. Canonical putative adaptive strategies were only partially idiographically effective, more so in the United States than in China, whereas maladaptive labels were highly corroborated across cultures. These findings underscore that the affective outcomes of polyregulation depend on idiographic quality rather than the number of strategies used. More broadly, this work illustrates how idiographic modeling can capture general processes of emotion regulation while revealing cultural differences. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at https://doi.org/10.1007/s42761-026-00398-1.