According to a recent study of gaming and aggression:<\/p>\n
\nVictorious gamers enjoy a surge of testosterone \u2013 but only if their vanquished foe is a stranger. When male gamers beat friends in a shoot-em-up video game, levels of the potent sex hormone plummeted.<\/p>\n
This suggests that multiplayer video games tap into the same mechanisms as warfare, where testosterone’s effect on aggression is advantageous.<\/p>\n
Against a group of strangers \u2013 be it an opposing football team or an opposing army \u2013 there is little reason to hold back, so testosterone’s effects on aggression offer an advantage.<\/p>\n
“In a serious out-group competition you can kill all your rivals and you’re better for it,” says David Geary, an evolutionary psychologist at the University of Missouri in Columbia, who led the study.<\/p>\n
However, when competing against friends or relatives to establish social hierarchy, annihilation doesn’t make sense. “You can’t alienate your in-group partners, because you need them,” he says.<\/p>\n