Abstract: [Purpose/Significance] This study explores the underlying conditions for older adults' use of social media to optimize their well-beings and empirically examines the impact of short video watching on older adults' mental health for policy implication. [Design/Methodology] Drawing on relevant theories from information sociology, communication psychology, and economics, we first proposed an analytical framework and research hypotheses based on the perspective of compensation-selective optimization theory, and then empirically examined the impacts of short video platform use on the levels of depression and happiness of older adults aged 60 and above with a nationally representative data in 2020. Our aim was to investigate the effective mediators of short video viewing behavior that integrates optimal compensatory selection for health and social needs in reducing physical and psychological social isolation among the elderly. [Findings/Conclusion] Evidence show that short video watching behavior is not significantly and directly associated with depressive symptoms or happiness among older adults, however can significantly affect health behaviors and social connectedness. Health behaviors and social connectedness both have a direct predictive impact on reducing the level of depression in the elderly and also play significant positive mediating roles in the correlation between short-video viewing and older adults' mental health. Importantly, there exists a nonlinear relationship between times spent on internet and mental health of the elderly. The positive mediating effect of health behavior would disappear if one uses Internet over 5 hours. [Originality/Value] This study innovatively analyzes impacts of rational and irrational new media platform use through a compensatory selective optimization theoretical perspective and examines mediating effects of reducing physical and mental isolation in the relationship of short video watching and mental health.

Keywords: Short video watching, Mental health, Older adults, Selection optimization compensation, Health behaviors, Psychological isolation