It is demonstrated that the subjective well-being (SWB) of older people greatly relies on their social participation. However, there are few studies on reciprocity beliefs as a mediating mechanism between social participation and SWB. In this study, 297 participants aged 60 and over in Chengdu, Sichuan Province, China, completed a questionnaire of social participation, reciprocity beliefs, and SWB. We used multiple linear regression and mediation analyses to verify the mediating effect of reciprocity beliefs. Results showed that social participation was positively relative to SWB and reciprocity beliefs, and reciprocity beliefs played an intermediary role in social participation and SWB. These findings suggest the importance of social participation for SWB, with reciprocity beliefs (behaviors) playing a positive mediating role, particularly in China. In conclusion, analysis of the mediating effect of reciprocity beliefs provides us with knowledge that could help in achieving a healthy old age. Additionally, this study opens up new perspectives of research.

Background: Although studies have demonstrated the relationship between the social trust and life satisfaction of older people, but existing studies have rarely considered the fewer studies have investigated social network as a mediating variable between social trust and life satisfaction. Methods: In this study, 297 participants (age: ≥60 years) in Chengdu, Sichuan Province, China, completed a questionnaire of social trust, social network, and life satisfaction. Structural equation model analysis and bootstrap methods were used to prove the mediating effect of social network. Results: Social trust was positively related to life satisfaction ( B =0.410; p <0.01) and social network ( B =0.472; p <0.01), social network was positively related to life satisfaction ( B =0.433; p <0.01). and social network played an intermediary role in the relationship between social trust and life satisfaction (indirect effects = 0.321, bootstrap 95% CI = [0.051, 0.968]). Conclusion: These findings suggest the importance of social trust for life satisfaction, with social network acting as a positive mediator, particularly in China. In conclusion, this study exploring the mediating effect of social network provides knowledge essential for ensuring a happy old age. The study results can help advance psychological research on life satisfaction of older people and suggest new intervention strategies in this field. We encourage increasing the expansion of social networks through various means to enhance the impact of social trust on life satisfaction of older people.