Responding to inequities: gorillas try to maintain their competitive advantage during play fights

Humans respond to unfair situations in various ways. Experimental research has revealed that also nonhuman species respond to unequal situations in form of inequity aversions, when they have the disadvantage. The current study focused on play fight behaviours in gorillas to explore for the first time if/how nonhuman species respond to inequities in natural social settings. Hitting causes a naturally occurring inequity among individuals and it was here specifically assessed how the hitting subjects and their partners engaged in the play chases that followed the hitting. The results of the present work showed that the hitting subjects significantly more often moved first to run away immediately after the hitting than their partners. These findings provide first evidence that nonhuman species respond to inequities by trying to maintain their competitive advantages. We conclude that nonhuman primates, like humans, may show different responses to inequities and that they may modify them depending on if they have the advantage or the disadvantage.