Temporal Mechanisms Underlying Systematic Mood Fluctuation: Re-evaluating Time and Day

Abstract

Positive and negative moods fluctuate systematically during our waking hours and throughout the course of a week; however, the mechanisms underlying these changes have not been fully explored. These systematic changes may be due to temporal influences, such as time of day and day of the week, as well as intertwined situational factors, such as daily routines, hassles, and stressors. Their collective influence on daily mood patterns has been examined, but previous research has not attempted to isolate and examine the unique effects. This study re-evaluated the influences of time and day over a 7-day period and examined the extent to which systematic daily mood patterns are driven by temporal versus situational influences. Results from nonlinear latent curve analyses indicated that temporal influences exerted differential effects on valence and arousal dimensions of mood, as well as positive and negative arousal components. Daily energy (i.e., arousal), but not affect, was entrained to the time of day, with only positive energy being additionally influenced by daily events. Day-to-day changes in weekday affect and positive energy were primarily driven by day of the week. Sunday, representing a transition to the new week, induced abrupt shifts in mood; however, the magnitude of these shifts was also determined by daily events.