Intraindividual variability in affect: Reliability, validity, and personality correlates

This article gives an overview of previous work on affect variability, discusses the methodological shortcomings of research on affect variability, and presents the results of an empirical study of intraindividual variability in primary emotions across time. The results of a daily assessment study using structural equation modeling and nonlinear regression analyses showed that intraindividual variability in affect is a multidimensional construct that is sufficiently stable to be considered a psychological trait and can be reliably measured by the intraindividual standard deviation. Intraindividual variability showed convergent validity with mean level scores and neuroticism but was sufficiently distinct to be considered a unique trait. This was particularly true of intraindividual variability in positive emotions; only about 10% of the variance could be accounted for by mean affect levels and the variables of the 5-factor model of personality.