Dynamics of evolving social groups

Noga Alon, Michal Feldman, Yishay Mansour, Sigal Oren, Moshe Tennenholtz

Research output: Contribution to journalArticlepeer-review

1 Scopus citations


Exclusive social groups are ones in which the group members decide whether or not to admit a candidate to the group. Examples of exclusive social groups include academic departments and fraternal organizations. In this article, we introduce an analytic framework for studying the dynamics of exclusive social groups. In our model, every group member is characterized by his opinion, which is represented as a point on the real line. The group evolves in discrete time steps through a voting process carried out by the group's members. Due to homophily, each member votes for the candidate who is more similar to him (i.e., closer to him on the line). An admission rule is then applied to determine which candidate, if any, is admitted. We consider several natural admission rules including majority and consensus. We ask: How do different admission rules affect the composition of the group in the long run? We study both growing groups (where new members join old ones) and fixed-size groups (where new members replace those who quit). Our analysis reveals intriguing phenomena and phase transitions, some of which are quite counterintuitive.

Original languageEnglish (US)
Article number14
JournalACM Transactions on Economics and Computation
Issue number3
StatePublished - Sep 2019

All Science Journal Classification (ASJC) codes

  • Computer Science (miscellaneous)
  • Statistics and Probability
  • Economics and Econometrics
  • Marketing
  • Computational Mathematics


  • Computational social choice
  • Price of anarchy
  • Social networks


Dive into the research topics of 'Dynamics of evolving social groups'. Together they form a unique fingerprint.

Cite this