Moving from traits to states: Examining the bidirectional day-level associations between personality states and sleep characteristics

Big-5 personality traits are robustly associated with sleep. Most theorizing points to day-level bidirectional processes; however, few studies have examined associations between personality traits and sleep at the day-level. To do so, we combined ecological momentary data from four samples (total sample size: 1,212 participants with 9,536 days of assessments) to conduct dynamic structural equation models examining bidirectional associations between personality states and sleep characteristics. Results supported bidirectional associations between personality states and sleep, though sleep influencing daily personality expression may be the more dominant force than personality states influencing nightly sleep. State neuroticism and conscientiousness were most closely connected to sleep, while the sleep characteristics of subjective sleep quality and daytime tiredness predicted all daytime personality states. Altogether, these findings elucidate day-level associations between sleep and personality traits that have been theorized as key processes that underpin trait-level associations.