Research shows gamers are more aggressive to strangers

Research has shown the testosterone levels of gamers playing competitive games increase when they beat a stranger, but decrease when they beat a friend; a finding which suggests that games can produce the same biological effect as real warfare.

In general, it's thought to be advantageous for people to release excessive testosterone when engaged in combat with strangers, as its affect on aggression can offer an advantage.

However, when competing against friends or family it doesn't make sense for the body to produce excessive amounts of the hormone, so levels remain low.

Proving this theory has always been difficult, reports New Scientist, because competitors in most activities naturally produce testosterone through physical exertion. Which is why evolutionary psychologist David Geary decided to conduct a study of more sedentary combatants - gamers playing Unreal Tournament 2004.

Studying 42 male university students playing the FPS in both cooperative team games and deathmatches, Geary found that the testosterone levels of winning team members against unknown teams spiked immediately after the tournament, especially among players who had contributed most to their team's victory.

However when members of the same team played against one another, the winning male's testosterone levels dipped even lower than that of his defeated teammate.

These results tally with those of a study conducted by anthropologist John Wagner, who studied competitive domino players on the Caribbean island of Dominica. When men played against people from their own village and won, their testosterone levels plummeted and also stayed low, whereas the loser's fell then rebounded. However, when men won matches against strangers from other villages, their testosterone levels tended to rise.