Variability is not flexibility: Emotion regulation switching predicts increased momentary distress when context is stable.

Recent research has challenged the assumption that specific emotion regulation (ER) strategies are universally adaptive, emphasizing instead the importance of fit of ER strategy to emotion-eliciting context (i.e., ER flexibility). However, most studies did not directly assess the context of ER but rely instead on measuring variability in ER as a proxy of flexibility. The current study aims at using a novel computational tool to directly assess ER-context interaction in two studies. Across a daily diary study (Study 1, N = 92, 1,149 diaries) and an ecological momentary assessment study (Study 2, N = 158, 12,217 observations), we applied the Bray-Curtis dissimilarity index-a computational tool that quantifies the type and degree of change between two profiles (i.e., patterns of ER and context)-to test whether ER effort scaling (i.e., endorsement changes) and strategy switching (i.e., replacement changes) predict momentary distress differently depending on whether context remains stable or changes. Greater moment-to-moment strategy switching predicted higher negative affect (Study 1) and momentary psychopathology symptoms (Study 2) when context was stable. These findings challenge the practice of using variability as a proxy for flexibility, underscoring that true flexibility cannot be evaluated without directly assessing context. We discuss implications for research on ER flexibility and psychopathology, emphasizing the need to prioritize rigorous context assessment in advancing clinical science. (PsycInfo Database Record (c) 2026 APA, all rights reserved).