In sexually-reproducing species, both intersexual and intrasexual competition can bolster reproductive fitness (Darwin, 1859; 1871). We are exploring how competition is expressed in human behavior, with a focus on direct aggression (physical violence, threats), indirect aggression (gossiping, social exclusion) in both peer (Arnocky & Vaillancourt, 2012) and romantic relationships (Arnocky, Sunderani, Miller, & Vaillancourt, 2012). Our recent work in this area has focused on intrasexual competition among young women (see Arnocky & Vaillancourt, 2015 for review).