This study investigated intraindividual change in affect in middle and old aged persons, using 6-year longitudinal data from a survey of individuals aged 50 to 76 years (N=3,107 at Wave 1) starting from 2007. Positive affect declined over time across age groups, whereas age differences were found for trajectories of negative affect. Negative affect showed an inverse U-shaped trend in middle age and remained stable in old age. Further, following a bottom-up framework, we examined whether contextual factors (gender, education, work status, marriage, and self-rated health) explained interindividual differences in intraindividual changes in affect. Positive affect decreased even after controlling for the correlates, while they partially accounted for changes in negative affect in old age. In particular, deterioration of affect in midlife was incongruent with existing literature. I discussed the possible mechanisms for trajectories of affect.
