Phan Tuan Q, Airoldi Edoardo M
Department of Information Systems, National University of Singapore, 117418, Singapore; and
Department of Statistics, Harvard University, Cambridge, MA 02138
Proc Natl Acad Sci U S A. 2015 May 26;112(21):6595-600. doi: 10.1073/pnas.1404770112. Epub 2015 May 11.
Social networks affect many aspects of life, including the spread of diseases, the diffusion of information, the workers' productivity, and consumers' behavior. Little is known, however, about how these networks form and change. Estimating causal effects and mechanisms that drive social network formation and dynamics is challenging because of the complexity of engineering social relations in a controlled environment, endogeneity between network structure and individual characteristics, and the lack of time-resolved data about individuals' behavior. We leverage data from a sample of 1.5 million college students on Facebook, who wrote more than 630 million messages and 590 million posts over 4 years, to design a long-term natural experiment of friendship formation and social dynamics in the aftermath of a natural disaster. The analysis shows that affected individuals are more likely to strengthen interactions, while maintaining the same number of friends as unaffected individuals. Our findings suggest that the formation of social relationships may serve as a coping mechanism to deal with high-stress situations and build resilience in communities.
社交网络影响生活的许多方面，包括疾病传播、信息扩散、工人生产力和消费者行为。然而，对于这些网络如何形成和变化，人们知之甚少。由于在受控环境中构建社会关系的复杂性、网络结构与个体特征之间的内生性，以及缺乏关于个体行为的时间分辨数据，估计驱动社会网络形成和动态变化的因果效应和机制具有挑战性。我们利用来自150万大学生在脸书上的样本数据，这些学生在4年里发送了超过6.3亿条消息和5.9亿条帖子，设计了一项关于自然灾害后友谊形成和社会动态的长期自然实验。分析表明，受灾个体更有可能加强互动，同时与未受灾个体保持相同数量的朋友。我们的研究结果表明，社会关系的形成可能是应对高压力情况和增强社区恢复力的一种应对机制。
