Daily stress reactivity: The unique roles of personality and social support

Abstract Background The processes through which social support exerts its influence in daily life are not well understood. Arguably, its salutary effects as an environmental variable might be construed as shared effects of personality. Method To test this possibility, we investigated the unique and shared effects of personality and social support on daily stressor exposure (social conflict, task strain) and on the within‐person association of stressor exposure with perceived stress. A community‐sample of N = 391 adults completed an ambulatory assessment protocol for two 2‐day periods with fixed hourly intervals spread across 16 hr. Results Consistent with our preregistered hypotheses, multilevel structural equation models returned that both, personality and perceived social support, predicted daily stressor exposure and moderated within‐person effects of daily stressors on perceived stress. In contrast to our hypotheses, received social support had no effect on daily stress processes. When Extraversion, Neuroticism, and social support were added as joint predictors, Neuroticism and Extraversion were related to stressor exposure, and further moderated the within‐person link between stressor exposure and stress experience, while perceived social support had an incremental beneficial effect on social conflict exposure and stress appraisal. Conclusion Social support does not increment the well‐established relationships between Neuroticism or Extraversion and stress reactivity.