Dispositional Optimism and Daily Stressor Reactivity: Trait Positive Affect as a Mediator of Affective, Behavioural, and Cognitive Outcomes

The current research examined if dispositional optimism buffers against negative consequences of daily stressor exposure. The work also provides a direct test of positive affect as a mediator, in line with the broaden-and-build theory of positive emotions. Study 1 utilised data from a US older-adult sample ( N = 958, M age = 62.57, 45% male) to examine optimism’s buffering role on affective (negative affect) and cognitive (rumination) outcomes. Study 2 extended these findings with a Singapore young adult sample ( N = 995, M age = 21.93, 27% male), incorporating behavioural outcomes (procrastination and impulsivity), introducing additional affective indicators (depressive and anxious mood), and broadening the cognitive domain to include cognitive failure in addition to rumination. Using multilevel regression and multivariate modelling, we found that optimism acted as a buffer against all indicators across both studies, except for anxious mood and procrastination. Trait positive affect mediated the associations between optimism and negative affect (in Study 1), rumination (in Study 1 but not in Study 2), and depressive mood, impulsivity and cognitive failure (in Study 2). These findings shed light on the boundary conditions of the buffering effect of dispositional optimism and the broaden-and-build theory of positive emotions.