主题：Easy to Be Selfish: When and Why is One Individual as Influential as Multiple Individuals
杨浙帅，新加坡国立大学博士，现任浙江大学管理学院市场营销系“百人计划”研究员、博士生导师。他的主要研究领域包括个体创造力、道德决策、顾客忠诚以及高科技在市场营销中的运用。他的文章发表在《Journal of Personality and Social Psychology》，目前正在主持国家自然科学基金青年项目《移动支付对消费者社交互动、购买决策的影响及其机制研究》，担任《Journal of Personality and Social Psychology》编委（Editorial Board Member）。
Past research on social influence finds that, all else being equal, a group of people engaged in a particular behavior is generally more influential than a single individual in inspiring others to adopt that behavior. The current research challenges this seemingly intuitive idea by showing that its validity depends on whether the focal behavior is selfish. Seven experiments show that while multiple people are indeed more influential than a single individual in encouraging unselfish behavior, a single individual can be just as influential as multiple people in encouraging selfish behavior. We present evidence that this phenomenon occurs because people generally have a preference for the selfish option and seek justification for their actions. Selfish behavior, whether exhibited by a single individual or a group of people, provides a convenient justification consistent with their preference for selfish behavior. When it comes to unselfish behavior, however, a larger group of influencers is required to counteract their self-benefiting tendencies. Supporting this mechanism, the effect is reversed when people have a pre-existing preference for unselfishness or when selfish behavior is difficult to justify.