关键词: 社会公平感, 社会比较, 隧道效应, 中等收入群体, 共同富裕

Abstract: Expanding the middle-income group is a strategic priority toward forming an olive-shaped society, promoting common prosperity, and achieving Chinese-style modernization. While sociologists and economists have provided numerous social and economic recommendations regarding the expansion of this group from perspectives such as income, employment, social security, and industrial economy, research and suggestions from psychologists on the social psychological implications of this expansion and how it can enhance public perceptions of fairness have been lacking.
By integrating the social comparison theory and tunnel effect theory, this study proposes a parallel mechanism involving subjective socioeconomic status (SSES) and upward mobility perception, and examines the moderating effects of income and economic development level. Data was sourced from the China General Social Survey (CGSS), covering eight periods from 2010 to 2021 (N = 61,751). Participants ranged in age from 18 to 70 years (M_age = 46.20 ± 13.72). This study combined the annual survey data from the CGSS and utilized provincial data for period simulation. Given that the research model involved both micro and macro variables, a hierarchical linear regression model was employed for analysis, with individual variables treated as level-one variables and provincial variables as level-two variables.
This study found that: (1) the proportion of the middle-income group was approximately 48%, which remained relatively stable, expanding the proportion of the middle-income group faces difficulties; (2) expanding the middle-income group can significantly increase the sense of fairness, which is only possible through SSES, and does not significantly predict the perception of upward mobility; in fact, the mediating effect of upward mobility perception was not significant; (3) at higher levels of economic development, expanding the middle-income group can enhance the sense of fairness for all groups, while at lower levels of economic development, it can only improve the sense of fairness for higher-income group, potentially reducing the sense of fairness for lower-income group; (4) the higher the level of economic development, the more the expansion of the middle-income group can enhance the sense of fairness for higher-income group through SSES, or for the lower-income group through the perception of upward mobility and SSES; but will potentially reduce the upward mobility of higher-income group; (5) the spatiotemporal heterogeneity test indicates that the research results of this study have a certain degree of robustness and generalizability.
Through empirical research, the study demonstrates that common prosperity should be achieved step-by-step. When the level of economic development is low, equal distribution may fail to create a high sense of fairness; however, when economic development reaches a higher level, greater emphasis should be placed on equitable distribution. Therefore, for contemporary China, it is necessary to promote sustained economic development within the framework of high-quality growth while adjusting the income structure becomes increasingly crucial. Additionally, attention should be paid to differentiating strategies for enhancing the sense of fairness among different groups of people in varying periods and contexts.

Key words: sense of fairness, social comparison, tunnel effect, middle-income group, common prosperity