Financial markets and macroeconomic environments are often characterized by positive externalities. In these environments, transparency may reduce expected welfare from an ex-ante point of view: public announcements serve as a focal point for higher-order beliefs and affect agents’...

Victorious alliances often fight about the spoils of war. This paper presents an experiment on the determinants of whether alliances break up and fight internally after having defeated a joint enemy. First, if peaceful sharing yields an asymmetric rent distribution, this increases the likelihood...

This paper considers evolutionarily stable decisions about whether to initiate violent conflict rather than accepting a peaceful sharing outcome. Focusing on small sets of players such as countries in a geographically confined area, we use Schaffer’s (1988) concept of evolutionary...

We study endogenous group formation in tournaments employing experimental three-player contests. We find that players in endogenously formed alliances cope better with the moral hazard problem in groups than players who are forced into an alliance. Also, players who are committed to expending...

This paper studies sabotage in tournaments with at least three contestants, where the contestants know each other well. Every contestant has an incentive to direct sabotage specifically against his most dangerous rival. In equilibrium, contestants who choose a higher productive effort are...