Abstract: Social class is a multifaceted construct that is rooted in both objective resources and subjective perceptions of socioeconomic status (SES) rank vis-à-vis others in society. An emerging body of research has shown that social class shapes both psychological experience and behaviors of individuals. In daily life, people usually face conflicts between self-interest and group-interest, which refer to mixed-motive situations called social dilemmas. The proper solution to those conflicts depends on mutual cooperation rather than mutual defection. To date, prior research has demonstrated that social class can affect how people balance the interest of themselves and others, and literature has mainly examined how individuals’ social class shapes their interaction with others. However, prior studies paid more attention to prosocial behavior such as helping and donating, with emphasis on the influence of self-class on behaviors. Here, we explored the effect of both self- and target- social class on cooperative behavior, investigated how target-class affect the relationship between self- social class and cooperation, and tested the mediating role of state trust in others in the moderation model. Accordingly, the present study consisted of two studies. In study 1, 236 college students took part in the survey and we assessed their subjective and objective social class, as well as cooperative behavior, so that the effects of self- social class on cooperation can been tested. In study 2, 94 college students, with different levels of subjective and objective social class, were randomly assigned to high and low perceived target-class priming conditions. Participants’ state trust and cooperative behavior to the target were then measured in a real-life give some dilemma. The measurement of their subjective and objective social class conducted the same tools as study 1. The results indicated that: (1) lower class individuals were significantly more cooperative than their upper class counterparts, and both individuals’ objective and subjective social class can predict their cooperative behavior; (2) the perceived target-class played a significant role in moderating the cooperative behavior of individuals from different classes. To be more specific, when perceived target-class was low, lower class individuals would engage in more cooperative behavior than their higher class counterparts; however, when perceived target-class was high, individuals’ self-class would not predict their cooperative behavior, (3) the state trust in the target mediated the moderating effect of target-class. The results support and expand the social cognitive theory of social class, suggesting that lower class individuals are more likely to focus on both self- and other-interests in order to survive and achieve life goals. The study also reveals that apart from self social class, target social class matters and people would perform differently when interact with lower class targets. In addition, state trust can mediate the moderation effect of target social class in the relation between self social class and cooperative behavior. These are not only further theoretical explorations, but also notable suggestions to improve higher class individuals’ cooperative behavior, especially their cooperation with lower class targets.

Key words: social class, target-class, social dilemmas, cooperation, state trust

摘要： 为了探究个体自身与他人的社会阶层对个体在社会困境中合作行为的影响及其作用机制，本研究通过问卷和实验研究来考察自身阶层的行为效应、互动对象阶层的调节效应以及信任有中介的调节作用。研究发现：（1）低阶层者倾向于比高阶层者表现出更多的合作行为；（2）感知到的互动对象阶层对不同阶层个体的合作行为存在显著的调节效应；（3）个体对互动对象的信任水平（即对他人合作行为的预期）对此调节效应起到中介作用。

关键词: 社会阶层, 互动对象阶层, 社会困境, 合作行为, 信任