title: Emergence of communities and diversity in social networks.
abstract: Communities are common in complex networks and play a significant role in the functioning of social, biological, economic, and technological systems. Despite widespread interest in detecting community structures in complex networks and exploring the effect of communities on collective dynamics, a deep understanding of the emergence and prevalence of communities in social networks is still lacking. Addressing this fundamental problem is of paramount importance in understanding, predicting, and controlling a variety of collective behaviors in society. An elusive question is how communities with common internal properties arise in social networks with great individual diversity. Here, we answer this question using the ultimatum game, which has been a paradigm for characterizing altruism and fairness. We experimentally show that stable local communities with different internal agreements emerge spontaneously and induce social diversity into networks, which is in sharp contrast to populations with random interactions. Diverse communities and social norms come from the interaction between responders with inherent heterogeneous demands and rational proposers via local connections, where the former eventually become the community leaders. This result indicates that networks are significant in the emergence and stabilization of communities and social diversity. Our experimental results also provide valuable information about strategies for developing network models and theories of evolutionary games and social dynamics.
authors.affiliation: School of Systems Science, Beijing Normal University, Beijing 100875, People's Republic of China.
authors.forename: Xiao
authors.initials: X
authors.lastname: Han
authors.affiliation: School of Finance, University of International Business and Economics, Beijing 100029, People's Republic of China.
authors.forename: Shinan
authors.initials: S
authors.lastname: Cao
authors.affiliation: School of Systems Science, Beijing Normal University, Beijing 100875, People's Republic of China.
authors.forename: Zhesi
authors.initials: Z
authors.lastname: Shen
authors.affiliation: Laboratory of Mathematics and Complex Systems, Ministry of Education, School of Mathematical Sciences, Beijing Normal University, Beijing 100875, People's Republic of China; zhangby@bnu.edu.cn wenxuwang@bnu.edu.cn hes@bu.edu.
authors.forename: Boyu
authors.initials: B
authors.lastname: Zhang
authors.affiliation: School of Systems Science, Beijing Normal University, Beijing 100875, People's Republic of China; zhangby@bnu.edu.cn wenxuwang@bnu.edu.cn hes@bu.edu.|Business School, University of Shanghai for Science and Technology, Shanghai 200093, China.
authors.forename: Wen-Xu
authors.initials: WX
authors.lastname: Wang
authors.affiliation: Department of Mathematics, Wilfrid Laurier University, Waterloo, ON N2L 3C5, Canada.
authors.forename: Ross
authors.initials: R
authors.lastname: Cressman
authors.affiliation: Center for Polymer Studies and Department of Physics, Boston University, Boston, MA 02215 zhangby@bnu.edu.cn wenxuwang@bnu.edu.cn hes@bu.edu.
authors.forename: H Eugene
authors.identifier: 0000-0003-2800-4495
authors.initials: HE
authors.lastname: Stanley
mesh_terms: D000533:Altruism; D005716:Game Theory; D006801:Humans; D007398:Interpersonal Relations; D012919:Social Behavior; D060756:Social Networking
keywords: communities; fairness; networks; social diversity; ultimatum game