Date of Award


Document Type


Degree Name

Master of Arts (MA)


College of Humanities and Social Sciences



Thesis Sponsor/Dissertation Chair/Project Chair

Ruth Propper

Committee Member

Kevin Askew

Committee Member

Kenneth Sumner


Human circadian rhythms are widely observed to fluctuate across the 24-hour circadian period, spanning cognitive, behavioral, and physiological domains. Circadian rhythm (CR) systems, particularly the sleep-wake cycle, are widely studied. Dysregulation of the sleep-wake cycle, common in shift work and mood disorders, diminishes mood regulation, resulting in increased negative mood or inappropriate mood responses. Although emotions have been investigated in the context of circadian variability in the sleep-wake cycle, circadian effects on emotional state per se have infrequently been examined. Previous studies suggest an increase in Positive Affect (PA) and decrease in Negative Affect (NA) as the day progresses, while the reverse occurs in the earlier hours of the day. Our study aimed to investigate circadian variation in PA versus NA, and extend these findings to the specific emotional states of Affection and Annoyance. As part of a larger study, thirteen male participants completed affect assessments using the Brief Mood Introspection Scale (BMIS) seven times over a 24-hour period. Primary findings corroborate previous research finding an increase in PA and decrease in NA during the evening, with the reverse occurring in the morning. Future research should include female participants, longitudinal designs, and objective measures of mood, such as cortisol or testosterone levels, in addition to subjective measures. These findings have clinical relevance, particularly for comparing patients' reported mood ratings with expected ratings based on circadian rhythm of mood. Early-morning NA may reflect normal circadian fluctuations, but late-day NA could indicate a severe clinical condition. In summary, this study replicates circadian patterns in PA and NA but finds unique circadian behaviors in Affection and Annoyance, demanding further exploration.

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Psychology Commons