Idiographic Momentary Profiles of Personality Facets

Personality psychology has long focused on between-person differences, often neglecting the dynamic, idiographic nature of personality as it unfolds over time. This study introduces idiographic momentary profiles—person-specific clusters of personality states—estimated using Gaussian finite mixture modeling. Drawing on experience sampling data from two independent undergraduate samples (N = 245; 15,833 total surveys), we demonstrate that individuals exhibit unique, multivariate personality state patterns that vary across time and situations. Findings reveal that (a) most individuals express multiple distinct profiles, (b) profile heterogeneity reflects both level and pattern differences, and (c) contemporaneous situational characteristics (i.e., DIAMONDS taxonomy) predict momentary profile expression. These results challenge static trait and typological approaches by highlighting the complexity and contextuality of personality dynamics. Our findings underscore the value of idiographic methods in advancing personality theory and measurement, offering a foundation for capturing the full scope of personality variability in daily life.Keywords: idiographic, personality dynamics, momentary profiles, situation characteristics