@article{2256,
  abstract     = {{Social psychology studies the "common enemy effect", the phenomenon
that members of a group work together when they face an opponent, although they otherwise have little in common. An interesting scenario
is the formation of an information network where group members individually sponsor costly links. Suppose that ceteris paribus, an outsider
appears who aims to disrupt the information 
flow within the network
by deleting some of the links. The question is how the group responds
to this common enemy. We address this question for the homogeneous
connections model of strategic network formation, with two-way 
flow of
information and without information decay. For sufficiently low linkage
costs, the external threat can lead to a more connected network, a positive
common enemy effect. For very high but not prohibitively high linkage
costs, the equilibrium network can be minimally connected and efficient
in the absence of the external threat whereas it is always empty and inefficient in the presence of the external threat, a negative common enemy
effect. For intermediate linkage costs, both connected networks and the
empty network are Nash for certain cost ranges.}},
  author       = {{Hoyer, Britta and Haller, Hans}},
  journal      = {{Journal of Economic Behavior & Organization}},
  pages        = {{146--163}},
  title        = {{{The Common Enemy Effect under Strategic Network Formation and  Disruption}}},
  doi          = {{10.1016/j.jebo.2019.03.011}},
  volume       = {{162}},
  year         = {{2019}},
}