Fluctuations in emotional valence and arousal are differentially linked to cognitive performance and subjective mental effort.

= 59) completed a 5-day ecological momentary assessment protocol with three assessments per day (682 completed sessions), combining repeated emotional state ratings with a working memory task and subjective mental effort reports. Associations were tested using linear mixed models. In Experiment 1, happiness and calmness loaded on a valence factor, whereas energy and fatigue loaded on an arousal factor. In Experiment 2, greater between-day variability in valence was associated with reduced working memory performance, driven by increased intrusion errors, together with lower perceived mental effort. In contrast, higher momentary arousal was associated with lower perceived mental effort without changes in working memory performance. Together, our results support a dissociation between emotional influences on cognitive control and on the subjective experience of effort. This dissociation suggests that emotion-cognition interactions in everyday life cannot be captured by a single affective dimension and that different emotional dimensions exert distinct effects on cognitive performance and its subjective experience. (PsycInfo Database Record (c) 2026 APA, all rights reserved).