Group conflicts often break out in which individuals have to choose who to support. Having more supporters tends to increase one's chances of success in conflict, so everyone would prefer to have more supporters. But support is scarce, and sometimes conflicts can arise between two people who...

We investigate in an economic experiment how people choose sides in disputes. In an eight-player side-taking game, two disputants at a time fight over an indivisible resource and other group members choose sides. The player with more supporters wins the resource, which is worth real money....

Research shows that many animal species have morphological and cognitive adaptations for fighting with others to gain resources, but it remains unclear how humans make fighting decisions. Non-human animals often adaptively calibrate fighting behavior to ecological variables such as resource...