Monday, 27 June 2011

Is male libido the ultimate cause of war?

"The face that launched a thousand ships ..." Dr Faustus retelling the legend of Helen and the Trojan War that was fought over her.
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male brain for conflict with other males, an effect that persists in modern man even though its usefulness is largely outdated.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."

ResearchBlogging.orgL 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.


Ben said...

This seems like very shaky evidence for the hypothesis largely because other less presumptive hypotheses don't appear to have been addressed. For instance, it could be that looking at females heightens sympathetic nervous system pathways which are associated with fight or flight impulses. Both sex and fighting are correlated with SNS activity as both are instantiations of arousal.

There's little reason to just jump to the conclusion than men get fighty because they're fighting over (let's hope that html tag worked) a woman when other hypotheses explain the phenomenon with less assumed entities. To rule out this explanation they could have had the sample use a stimulant to increase adrenalin activity and see if the same findings bore out.

It's an interesting study nonetheless and seems to suggest that decreasing the amount of sexual material in services whose function it is to fight could hamper efficacy.

Neal W. said...

Are there any studies on the number of sexual partners for members of the military today?

Christian Jarrett said...

hi Ben
thanks for your comments. Re your suggestion that the effects could simply be a consequence of nervours system arousal - I think if that were true that you would expect the effects to be far less specific. i.e. you'd expect the participants to spot farmers more quickly, not just soldiers. And you'd expect speeded performance with agression words, not just war words.

Anonymous said...

More reason for electing qualified women to leadership positions in government. Hypothesis: qualified women leaders will contribute to cooperative, win-win solutions to territorial, economic and social conflicts.

Ben said...


Untrue, the fact that we haven't found this phenomenon in women doesn't mean women aren't laboured with similarly negative traits in other areas. It sets a very dangerous precedent when we start demanding members of a specific race/gender/sexuality based upon general rules: what do we do when a study shows, perhaps spuriously, that x group is worse a certain job? Flat out ban them or discourage them? Such moves are highly anti-egalitarian.

As a hypothetical, if women were proved to be less coldly rational than men would you advocate removing them from clinical positions like medicine and science? The sword cuts both ways and once we say we're fine with discrimination then it's a very slippery slope.


Hi Chris! Love the blog, by the way. It's been bloody ages since I studied psychology, but I still find myself glued to this blog.

I'm not sure if SNS activation provides such generalised benefits. PNS systems are antagonised, so we'd expect to see such systems suffer in performance. It seems evolutionarily disadvantageous to permit irrelevant cerebral associative functions (e.g food and communal related items such as farmers) to continue in fight or flight mode, but I can't remember any such studies on the matter so I could be wrong.

I bow to your superior knowledge of psychology. If you say that the functions of SNS activity are too generalised to act as an explanation then I'll accept the study until I can think up another hypothesis that fits the findings.

As a side note, do you know if they (or anyone else) tested how easily these impulses towards aggression are overcome by the sample? If they're evolutionary primes which are easily overridden by the conscious mind then they're an irrelevance.

Anonymous said...

Women don't care about attractive men. Had Mr. Chang showed them pictures of RICH men the results would've been the same!

Christian Jarrett said...

@Ben Thanks Ben for your kind words re the blog. I'm just playing devil's advocate really. But I'd have thought you'd seem some effects of a fight/flight response (if that's what was triggered by the sexual stimuli) on non-war related performance. For example, you'd think a rush of adrenaline would speed performance at spotting any target on a screen, not just soldiers. The highly specific effects observed here suggest there really is some facilitative link between sex and war/fighting, at least in this set of participants. The main short-coming as I see it, is the use of individual computer-based tasks - the ecological validity is severely lacking. The researchers didn't look at attempts to override the war-related effects. But even if the participants were capable that would not make the findings an irrelevance - they'd still have theoretical relevance and warrant an explanation.

@Anonymous 11:43. Good point, they should have tested that!

Ben said...


True, irrelevance was too harsh a word. All facts have relevance, that's the underlying basis of science. What I meant to say was that if these primes are easily overridden then it has little practical relevance with regards to application (e.g. deciding whether to discourage mixed male/female units in situations where unprovoked aggression could be detrimental to function such as policing).

It's true that the ecological validity is pretty shoddy, but I can't really think of an ethical way one could better the validity. Obviously, putting the sample in a situation where they can act out aggression physically (because it's precursors to physical aggression they appear to be testing for here) would lead to all sorts of ethical complications. Perhaps a similar computer program in which the sample can either deal with a problem diplomatically or with brute force?

Furthermore, I'd be interested to see the sampling methods here too. Were the participants paid or were they university students? Were they generally representative or was a particular socioeconomic group unrepresentatively favoured? It'd also be interesting to see if these finding held true in other nations, given Asia's collectivism (or is Hong Kong excepted from collectivism? I seem to remember that being the case, but it's been a few years since I studied this stuff).

And don't sweat it, I realise you're playing devil's advocate. Proper hypotheses should face rigorous criticism until they eventually become honed by the criticism to the point of becoming working hypotheses. Cheers for the debate nonetheless, keeps things interesting.

Anonymous said...

Just wondering if some sort of test for women could be set up that utilized babies or children in some way -- perhaps hungry kids, or kids shown to be in peril.

When my adventurous daughter was little, there were several times I had to think and act fast to remove her from danger -- I surprised myself incredibly by how strong and quick I was.

Bruce Johnson said...

I enjoyed both the article and the subsequent debate. In fact I am hoping at some point to do a higher degree in the evolutionary basis of male group aggression. Can anyone please recommend a UK university suitable for that area of study ?

Outlaw said...

Wars also get fought so that nervous mommies can feel like their precious little broods are safe. I would say that informs the reasoning behind modern warfare (specifically vs. Terrorism) for sure.

Stella said...

Which brood is safer/more nurtured: The one who lives in a world with no war, or the one who lives in a world of war where their fathers die in battle?

What is being argued here is that one type of chromosome has a much higher tendency toward violence. Without it, there would be almost no war to deal with in the first place.

Mr. Jones said...

So, the coup of 1461 was what? Penis envy? Most eunuchs had no, or non-functional testicles but still staged the coup, were still aggressive, were still brutal. Their interest in the opposite sex was, without proper equipment or hormones, shall we say, purely academic. What then drove the coup, and the several eunuch Generals of Chinese history?

More likely this isn't evidence of a wider pattern of aggression but benevolent sexism. I think the distinction needs to be made here that social protective functions are primarily defensive, not offensive. The result may seem the same, but the character of the variables are different.

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