Aggression is wide-spread in nature and seems to serve, among others, an important role in the interspecies competition for resources. In this talk, we argue that displaying aggression as a means to signal action tendencies (in particular, the probability to continue an encounter) is beneficial for social groups and show that discriminating between "own" and "other" is more beneficial than treating "other" the same as "own". In particular, we demonstrate that aggression plays a crucial role in strategies applied to "other". To test the theoretical prediction, we define seven basic agent types which give rise to 42 different discriminating agents, i.e., agents with different strategies for "own" and "other". In extensive simulation studies we show that discriminating agents, which assume an aggressive attitude towards others, while playing a strategy that distributes resources fairly among "own", are ultimately the most successful ones. We discuss the implications of these results for natural and artificial agents and conclude with a brief outlook on further studies.