Personality and chronotype: a latent variable perspective

IntroductionChronotype refers to the entrainment phase of daily activity patterns to the day-night cycle. The relationship between chronotype and personality traits has long interested popular and scientific audiences. However, personality traits measured by self-report questionnaires are correlated, with various theories explaining their common variance. This study aims to explore whether it is the unique or common variance in personality dimensions that drives their association with chronotype. MethodsUtilizing a sample of 267 healthy volunteers from the Budapest Sleep, Experiences, and Traits Study (BSETS) with the Big Five Inventory, the Munich Chronotype Inventory, and objective 7-day EEG monitoring of day-night rhythms, we used confirmatory factor analysis to separate common and unique variances in personality dimensions. ResultsA single-factor model fit the data well and the common factor was correlated with self-reported chronotype. Model fit was improved only if a residual correlation to Openness was added. EEG-based sleep timing did not correlate with personality dimensions. DiscussionThese findings suggest previous correlations between chronotype and personality traits were confounded by shared personality variance. Higher scores on the common personality factor, reflecting either a favorable personality profile or positive self-presentation, were associated with an earlier chronotype, with an uncertain relationship to specific personality dimensions.