Lifespan trajectories of negative and positive affect: A coordinated analysis of 14 longitudinal studies.

Lifespan developmental theories suggest age-related shifts in motivation, cognition, emotion regulation, and stressor experience lead to changes in mean levels of negative and positive affect across the lifespan. The present research used coordinated data analysis to examine mean-level affective trajectories in 186,752 participants ranging from 11-104 years old across 14 longitudinal studies. Random-effects models were used to estimate meta-analytic effect sizes. On average, negative affect decreased until early older adulthood, and then remained stable throughout older adulthood. Meanwhile, positive affect remained stable across most of the younger and middle-aged adult lifespan, before starting its descent in later middle-aged adulthood and continuing to decline throughout older adulthood. Studies with older samples showed a clearer flattening effect of negative affect and steeper decline of positive affect in late-life relative to younger samples. These findings suggest that lifespan developmental affect trajectories are nuanced and not a direct inverse of each other.