Our experimental analysis of alliances in conflicts leads to three main findings. First, even in the absence of repeated interaction, direct contact or communication, free-riding among alliance members is far less pronounced than what would be expected from non-cooperative theory. Second, this...

This study compares contests with exogenous alliance formation under proportional sharing rules with contests among individual players in a laboratory setting. The standard equilibrium predictions are identical for all players because the proportional rule ensures the same payoff incentives for...

We study conflict between two groups of individuals. Using Schaffer's (1988) concept of evolutionary stability we provide an evolutionary underpinning for in-group altruism combined with spiteful behavior towards members of the rival out-group. We characterize the set of evolutionarily stable...

We study an all-pay contest with multiple identical prizes ("lifeboat seats"). Prizes are partitioned into subsets of prizes ("lifeboats"). Players play a twostage game. First, each player chooses an element of the partition ("a lifeboat"). Then each player competes for a prize in the subset...

Victorious alliances often fi ght about the spoils of war. We consider experimentally when members of victorious alliances accept a peaceful division of the spoils, and when they fi ght against each other, and how the inability to commit to a peaceful division affects their effort contributions...

We experimentally study endogenous alliance formation and contest effort choices in a generic three-player contest. Differences in intrinsic or extrinsic incentives to expend effort cause self-selection. Weakly motivated players have an incentive to enter into an alliance and to free-ride on...

In many real-world contests (political elections / lobbying for public projects), contestants try to engage supporters (unemployed youth / local residents) to fight for them. Such contests have the following features: a significant part of a contestant's supporter compensation is contingent upon...

In the world of satin bowerbirds, the male-birds engage in a contest among themselves to win their mates: they spend considerable time and effort in decorating their own bowers, and then attempt to destroy the decorations of their rivals' bowers. The female-birds, in turn, select their mates on...

This paper studies the attack-and-defence game between a web user and a whole set of players over this user's ‘valuable secrets.' The number and type of these valuable secrets are the user's private information. Attempts to tap information as well as privacy protection are costly. The...

We consider two players' choice about the formation of an alliance ahead of conflict in a framework with incomplete information about the strength of co-players. When deciding on alliance formation, players anticipate the self-selection of other players and the informational value of own and...