【摘要】 在中国人口老龄化加速发展与社会数字化转型的双重背景下，老年群体面临传统社会联结弱化和数字鸿沟导致的社会参与困境。微信作为当今社会主流社交媒体平台，其核心功能的朋友圈通过动态分享、互动评论等方式成为银发族维系社会关系的重要虚拟空间。现有研究多关注社交媒体使用对老年人社会心理收益、数字鸿沟跨越的影响，却较少探讨社交媒体使用与老年人社会资本之间的关系。本文基于2020年和2022年中国家庭追踪调查（CFPS）数据，运用熵值法测算社会资本指数，并构建固定效应模型实证检验微信朋友圈使用对老年人社会资本积累的影响及其异质性与作用机制。研究结果显示：适度的朋友圈使用能扩大社会网络、培育社会信任，进而促进社会资本的正向积累；但当使用超过一定阈值，即分享频率超过每周一至两次，正向效应会逐渐转为负向，呈现倒“U”形特征。该结论在经过限定样本范围、替换变量等稳健性检验后依然成立。同时，考虑可能存在的反向因果及遗漏变量偏误等问题，本文使用工具变量法处理内生性偏差，进一步确保基准模型结果的可靠性。异质性分析表明朋友圈使用对老年人社会资本的影响存在显著的城乡差异：尽管朋友圈使用对城镇老年人的社会资本增益更加明显，但城镇老年人也更容易达到使用阈值，即显示更陡峭的倒“U”形特征；相比之下，朋友圈使用对于乡村老年人社会资本的倒“U”形影响更为平缓，反映出乡村老年人面临的数字饱和风险较低。此外，初始社会资本较低的老年群体在朋友圈使用中获益更大，显示社交媒体的使用具有一定的社会补偿功能，有助于弥合老年群体间的资源差距。机制分析结果表明朋友圈使用通过缓解老年人孤独感、提升老年人自评社会地位，最终对其社会资本水平产生影响。为帮助老年人享受数字红利、积累社会资本，在政策的制定和实施方面应倡导适度使用社交媒体，引导建立健康的数字社交习惯，针对城乡老年人在数字素养和社交模式方面的差异精准施策，定向支持低社会资本群体以及提升老年人在数字参与过程中的价值认同感。更多还原

【Abstract】 In the context of China’s rapidly aging population and the accelerating pace of digital transformation,Chinese older adults are confronted with twofold challenges:the weakening of traditional social ties and restricted opportunities for social participation due to the digital divide. As the core function of WeChat,which is the dominant social media in China,Moments has emerged as an essential virtual space for older adults,enabling them to sustain social connections through sharing updates,commenting,and liking. While existing studies have focused more on how social media use affects older adults’ psychological benefits and helps bridge the digital divide,relatively little attention has been paid to the relationship between social media use and social capital among older adults. Using data from the 2020 and 2022 China Family Panel Studies(CFPS),this study employs the entropy weighting method to construct a social capital index and builds fixed effects models to empirically examine how the usage of WeChat Moments affecting older adults the accumulation of social capital,along with its heterogeneity and underlining mechanisms. Results show that:moderate use of Moments expands older adults’ social networks and fosters social trusts,thereby facilitating the accumulation of social capital. However,when usage surpasses a certain threshold—specifically,posting more than once to twice per week—the positive effects gradually turn negative,forming an inverted U-shaped pattern. This result remains robust after a series of tests including restricted sample analysis,variable substitution,and the inclusion of potential omitted variables. In addition,to address potential issues such as reverse causality,and omitted variable bias,instrumental variable approaches are applied to ensure the reliability of the baseline results. Heterogeneity analysis reveals significant urban-rural differences upon the impact of Moments use on social capital:although urban older adults benefit more from Moments use,they are also more likely to reach the threshold of digital oversaturation. In contrast,rural older adults show a flatter inverted U-shaped relationship,indicating a lower risk of saturation. Furthermore,individuals with initially lower levels of social capital benefit disproportionately more from Moments use,highlighting the compensatory role of social media in mitigating social resource disparities among older adults. Mechanism analysis indicates that the impacts of Moments use on social capital operate through two pathways:alleviating loneliness and enhancing self-perceived social status. To help older adults benefit from the digital era and foster the accumulation of social capital,policy efforts should encourage moderate use of social media,cultivate healthy digital habits,tailor interventions to urban-rural differences in digital literacy and social behavior,provide targeted support to low-social-capital groups,and enhance older adults’ sense of value and identity in the process of digital engagement.更多还原