Intrinsic Emotional Fluctuation in Daily Negative Affect across Adulthood.

<p><b>OBJECTIVES: </b>The study explored daily negative affect (NA) fluctuation, its associations with age, and its developmental characteristics.</p><p><b>METHOD: </b>The sample (n = 790) was drawn from the Midlife Development in the United States; participants completed two 8-day daily diaries 10 years apart. Multilevel models were estimated within each diary component, where two single daily NA (depression and nervousness) and daily NA diversity were predicted separately by daily stressor exposures, physical health symptoms, age, gender, education, and neuroticism. The variances of within-person residual were output for single NA and NA diversity as intrinsic emotion fluctuation (IEF) within each diary component (i.e., controlled for within- and between-person contextual factors). Then multilevel growth models were fit to explore the developmental characteristics of day-to-day IEF across 10 years.</p><p><b>RESULTS: </b>At the daily level, older age was associated with less IEF in depression and nervousness. Over time, IEF in depression decreased. Additionally, IEF in NA diversity increased for older participants longitudinally.</p><p><b>DISCUSSION: </b>IEF represents a new conceptualization of midlife individuals' daily emotional ups and downs, specifically, the intrinsic within-person volatility of emotions. The magnitude of IEF and its longitudinal dynamics may have implications for health and well-being of middle-aged adults.</p>