The influences of social value orientation on prosocial behaviors： The evidences from behavioral and neuroimaging studies

社会价值取向是相互依存情境下人们对自己和他人分配结果的一种稳定的社会偏好,它影响个体在社会困境中的亲社会行为.研究者常用三优势量表和滑块测验测量个体的社会价值取向,并将其分为亲社会型和亲自我型.以往研究发现,社会价值取向的表达具有自发性和稳定性,且亲社会型个体相比亲自我型个体,表现出更多的信任、合作和公平决策等亲社会行为.通过分析,总结了社会价值取向通过以下4个方面影响亲社会行为：内部动机的不同;对他人行为的预期;社会责任感的差异;两类个体在社会学习方面存在差异.未来研究可进一步考察社会价值取向与共情及与其他人格特质的交互作用对亲社会行为的影响以及相关的神经生化机制. ＂Economic Man Assumption＂ proposed that humans are rational, whose only goal is to pursue their maximum selfinterest. However, costly prosoial behaviors, such as helping, comforting, or donation, are commonly seen in daily life. Researchers put forward social value orientation（SVO） to explain why people exhibit such behaviors. SVO refers to a stable preference for outcomes for self versus others in interdependent situation, which further affects prosocial behaviors in social dilemmas. The commonly used measurements of SVO are the Triple-Dominance Scale and the Slider Measure. Based on these measures, SVO is classified into two categories： prosocial value orientation, and proself value orientation. The latter one is further subdivided to individualistic and competitive value orientations. People with prosocial orientation tend to maximize joint interest, people with individualistic orientation tend to maximize absolute outcome, while people with competitive orientation tend to maximize relative outcome. Previous studies have suggested that SVO can express automatically, and stably influence social behaviors. This article reviewed existing researches and mainly discusses its influence on trust behavior, cooperation and fair decisions in social contexts. A growing body of evidence suggests that prosocial individuals show more trust behaviors, cooperation, and fair decisions, which are further reflected on neural activities. Specifically, temporal-parietal junction（TPJ）, insula and anterior cingulate cortex（ACC） show stronger activation when prosocials choose to cheat compared to be honest/trustworthy in trust game, while for proselfs there are no significant differences. In social dilemma games, prosocials show more cooperative behavior, accompanied by increased activation in lateral orbitofrontal cortex（OFC）, anterior superior temporal sulcus（a STS） and inferior parietal lobule, which brain regions are relevant to norm compliance, routine moral judgment, and social awareness. While for proselfs, increased activation is found in dorsolateral prefrontal cortex（DLPFC）, which is relevant to calculation. Researches have also found prosocials make more rejection to unfair allocation, and the degree of inequity aversion in prosocials is predictable from amygdala activity. In light of existing literature, we summarized four aspects of how SVO affects prosocial behaviors. The first one is that prosocials have a stronger internal cooperation motivation relative to proselfs so that prosocial behaviors are processed automatically for prosocials. Second, prosocials have a higher expectation of others’ prosocial behaviors, this expectation in turn influences himself/herself’s behaviors. The third is that prosocial ones show more social responsibility in social interaction that they tend to maximize joint outcome. Last but not least, individuals with different SVOs show different social learning patterns which affects information collection and decision making during social interaction. Before the end, we propose several research directions. First is the differences in social learning patterns between individuals with different SVOs. Secondly, the interactive effects of SVO and other personality traits, such as empathy and trust, on prosocial behavior need to be investigated. More neural biochemical researches which focus on neurotransmitter as well as gene of different SVOs are also required. At last, in order to better apply research results to real life, ecological validity of research need to be improved.