Abstract: Decline of cognitive function is considered as a part of normal ageing, and it may increase the risks of dementia and disability. A growing interest lies in exploring the risk factors and influence mechanisms of cognitive function. Social isolation is an object state caused by the lack of social connections, and is regarded as a huge risk factors determining cognitive function among older adults. A large amount of quantitative studies have proposed the evidences that social isolation is negatively associated with cognitive function among western older adults. However, no study explores the relationship among Chinese older adults, whose social connections patterns are different from western. This study hypothesizes that social isolation is negatively associated with cognitive function among Chinese older adults. Few studies explore the influence mechanisms between social isolation and cognitive function. The psychological mechanism of cognitive function proposes the point that negative emotions may cause the limitation of hippocampal and further triggers the cognitive function impairment. Loneliness and depression are typical negative emotions among older adults, and amounts of quantitative evidences support their negative impacts on cognitive function. Besides, social isolation means few social connections and is the predictor factor of loneliness and depression. Therefore, this study hypothesizes that loneliness and depression play mediating roles between social isolation and cognitive function among older adults. Furthermore, numerous studies support the significant association between loneliness and depression. Therefore, this study also hypothesizes that loneliness and depression play a chain mediating effect between social isolation and cognitive function. The 2014 wave of China Longitudinal Aging Social Survey (CLASS) was employed in this study. After excluding those samples with missing data of key variables, a total number of 5,162 older adults were selected. SPSS 20.0 and AMOS 20.0 were used in this study to analyze data. At first, this study examined the common method deviation analysis. Secondly, this study reported the descriptive results and the correlation analysis between main variables. Thirdly, this study constructed structural equation models (SEM) and tested the mediating effects. The results are as follows: (1) social isolation is significantly associated with older adults’ cognitive function. (2) depression plays a mediating role in the relationship between social isolation and cognitive function, while the mediating role of loneliness isn’t significant. (3) loneliness and depression play a chain mediating role in the relationship between social isolation and cognitive function. Some theoretical and practical contributions are proposed in this study. This study expands the existing research related to the association between social isolation and cognitive function among Chinese older adults, and also contributes to understanding their underlying mechanism through paying attention to the psychological mechanism of cognitive function. In addition, the results have some important implications, it’s urgent and necessary to take measures to cope the huge challenges of social isolation on older adults’ cognitive function. Depression is a crucial mediating mechanism that understand the relationship between social isolation and cognitive function, thus it’s important to screen and diagnose older adults’ depression. The chain mediating effect also reminds us to take measures to reduce loneliness and block the negative effects of social isolation on cognitive function.

Key words: social isolation, cognitive function, loneliness, depression, older adults

摘要： 考察中国文化背景下社会隔离对老年人认知功能的影响，并从认知功能心理影响机制的角度探究孤独感和抑郁的链式中介作用。基于中国老年社会追踪调查（CLASS），对5162名60岁以上老年人的社会隔离、孤独感、抑郁和认知功能进行研究。结果发现：（1）社会隔离显著负向预测老年人的认知功能；（2）社会隔离可以通过抑郁的独立中介作用以及孤独感和抑郁的链式中介作用间接预测老年人的认知功能，但是孤独感的独立中介作用不显著。研究结论对于减少社会隔离对老年人认知功能的消极影响具有积极意义。

关键词: 社会隔离, 认知功能, 孤独感, 抑郁, 老年人