From the mighty clash of two stags rutting, to the dawn raid of a chimpanzee, much violence in nature is perpetrated by males fighting each other in competition for female mates. A new study claims it's a similar story with humans. Cultural differences, limited resources and technological developments all play a role, but a team of psychologists based in China and Hong Kong believe the ultimate cause of human war rests with the male libido. Historically, they argue that the lure of an attractive female primed the male brain for conflict with other males, an effect that persists in modern man even though its usefulness is largely outdated.
Across four experiments Lei Chang and his team showed that pictures of attractive women or women's legs had a raft of war-relevant effects on heterosexual male participants, including: biasing their judgments to be more bellicose towards hostile countries; speeding their ability to locate an armed soldier on a computer screen; and speeding their ability to recognise and locate war-related words on a computer screen. Equivalent effects after looking at pictures of attractive men were not found for female participants.
The effects on the male participants of looking at attractive women were specific to war. For example, their ability to locate pictures of farmers, as opposed to soldiers, was not enhanced. Moreover, the war-priming effects of attractive women were greater than with other potentially provocative stimuli, such as the national flag. Finally, the men's faster performance after looking at women's legs versus flags was specific to war-related words, as opposed to merely aggressive words.
"The mating-warring association, as shown in these experiments ... presumably unconsciously propels warring behaviour because of the behaviour's past, but not necessarily current, link to reproductive success," the researchers said. They conceded their study had several limitations, not least that war is a collaborative endeavour whilst they had studied individual responses. However, the new results chime with past lab research, showing for example that men, but not women, respond to intergroup threat by increasing their within-group cooperation. And they chime with anthropological research, which has found male warriors in traditional tribal societies have more sexual partners than other men, as do male members of modern street gangs.
"... This is among the first empirical studies to examine the potential mating-warring association," the researchers concluded. "As such this study adds to the diversities of evidence on the effects of mating motives in human males as well as motivating further discussions of the origins of human warfare."
L Chang, H Lu, H Li, and T Li (2011). The Face That Launched a Thousand Ships: The Mating-Warring Association in Men. Personality and Social Psychology Bulletin DOI: 10.1177/0146167211402216
This post was written by Christian Jarrett for the BPS Research Digest.