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The Psychology of Going to War

Is it ultimately all about men wanting to impress women?

War is a male activity. Organized fighting and killing by groups of women against other groups of women has simply not existed at any point in human history, and given the wide range of diversity to be found across human cultures, the consistency with which males are the organizers and perpetrators of group conflict has led many scholars to conclude that the male propensity for group violence is rooted in more than the learning of culturally prescribed gender roles.

Evolutionary psychologists have studied war and conflict with the assumption that a predisposition for warfare has evolved in males because it has historically (and prehistorically) enhanced their reproductive success. Hence, the origins of warfare can ultimately be found in the competition between males for status and access to women.

Male Competition for Mates Is Intense

The adaptive problems faced by men and women throughout history were quite different, and aggression proved to be a more adaptive response for males than for females. Sexual competition for mates has always been more intense among males than among females, especially in the polygamous societies that appear to have been typical in the prehistoric human world.

The stakes were very high for men in this environment, as the winners of this competition would come away with the greatest number of women (and the most desirable women). The losers ran the risk of genetic annihilation by their failure to successfully win the status and resources necessary to attract mates. Historically, powerful men have always enjoyed greater sexual access to women than men lower in the pecking order, and violence, including war, can often be traced to this grim struggle for status and mates among men.

Violence committed against the right people at the right time has commonly been a ticket to social success. For example, among the Yanomamo of South America, men who had killed other men, especially during wars and skirmishes with other villages, acquired significantly more wives than men who had not yet killed anyone. Because having killed someone in war was often good for one's reputation, many societies developed ceremonies for recognizing such accomplishments. In modern societies, these take the form of prestigious awards such as the Congressional Medal of Honor in the United States, and many countries have national holidays to celebrate the heroism of those who have fought and/or died in wars.

Are War Heroes Selfish?

War heroes are held in such high esteem because they seem to act in a noble and virtuous manner, setting aside any thoughts of their own well-being for the good of their group, tribe, or nation.

Or do they?

Evolutionary psychologists believe that even apparently selfless impulses such as heroism must provide some adaptive advantage for individuals. Costly Signaling Theory suggests that conspicuous war heroism may be a way for individuals to advertise desirable personal qualities that increase the likelihood that they will be chosen as a mate or an ally and be positioned for access to future resources.

Many studies demonstrate that people who sacrifice for the group by engaging in costly altruistic activities do in fact achieve elevated social status, respect, and recognition as a result of their public selflessness. For a costly signal to be effective, it must honestly convey valuable information about the individual sending the signal, and it must be impossible to fake. No researchers suggest that heroes consciously sit down and calculate all of the benefits that will come their way if they survive the heroic action. Rather, it is thought that such impulses have been selected for because heroic behavior has provided competitive advantages for men throughout human history.

Have Men Evolved to Make War?

Dutch psychologist Mark Van Vugt has proposed the Male-Warrior Hypothesis as a way of explaining the results of research demonstrating that men show stronger group identification and more cooperation with ingroup members than do women during times of threat from outside groups. His theory suggests that men have evolved a predisposition to engage in collective cooperative aggression against outgroups, a tendency that has likely been strongly reinforced through cultural traditions and socialization.

A team of European psychologists explored the proposition that war provides an arena for men to compete and impress both their male rivals and females who might be potential mates. In one study, they found that 464 American men who had won the Medal of Honor during World War II eventually had more children than other U.S. servicemen who had not been so heroically distinguished. This is consistent with the idea that heroism gets rewarded with greater reproductive success.

In a second study, 92 women rated the sexual attractiveness of men who had behaved heroically in war as being higher than that of soldiers who had served but not been identified as heroes. Tellingly, women did not show this increased attraction toward men who had behaved heroically in sports or business situations. A third study revealed that behaving heroically in war does not increase the attractiveness of female war heroes to men. In summary, heroism in times of war is sexier than any other kind of heroism, but only for men.

Young men are particularly concerned with status and heroic opportunities for sound evolutionary reasons. In early human societies, competitive success or failure in early adulthood determined a man’s standing in a social group for the rest of his life. It wasn’t possible to simply hit the “reset” button and join another group, so what happened during the teen years mattered a lot. For this reason, high-risk competition between young males provided an opportunity for “showing off” the abilities needed to acquire resources, exhibit strength, and meet any challenges to one’s status.

Consequently, heroic or even recklessly daredevil behavior was rewarded with status and respect—assuming, of course, that the young man survived the ordeal. Displaying heroism in times of war was a primary way of accomplishing these goals. Hence, it should not be surprising that historical data confirm that the concentration of young men in a population is one of the best predictors of when a society is most likely to go to war.

The idea that men compete with each other to impress women has clearly been around for quite some time. For example, the Sioux warrior Rain in the Face once commented on the fact that the presence of women in a war party caused his warriors to vie with one another more intensely in displaying their valor.

Today, the popularity of sports undoubtedly developed as a constructive alternative for dealing with the proclivities of young males that evolved in a very different time. In a legally sanctioned gladiatorial arena, young men compete to exhibit the same skills—throwing, clubbing, running, wrestling, tackling, hand-eye coordination—that would have made them successful fighters and hunters in the ancestral environment.

How Could Such Risky Behavior Be Adaptive?

War is costly and risky, and for male psychology to have evolved a predisposition for going to war, several essential conditions must be met. John Tooby and Leda Cosmides have identified four conditions that would be particularly important. First of all, successful soldiers must have greater sexual access to women than non-combatants. Secondly, coalitions of fighters must believe that they will be victorious. Thirdly, the rewards that each warrior receives must be proportionate to the risks he has taken and the importance of his contributions. In other words, cheaters should never prosper. And finally, men going to war must not know for sure who will live and who will die; there must be a protective “veil of ignorance.”


    Further readings:

    Archer, J. (2006). Testosterone and human aggression: An evaluation of the challenge hypothesis. Neuroscience and Behavioral Review, 30, 319-345.

    Browne, K. R. (2012). Band of brothers or band of siblings? An evolutionary perspective on sexual integration of combat forces. In T. K. Shackelford & V. Weekes-Shackelford (Eds.), Oxford handbook of evolutionary perspectives on violence, homicide, and war (pp. 372-392). New York: Oxford University Press.

    McAndrew, F. T. (2009). The interacting roles of testosterone and challenges to status in human male aggression. Aggression and Violent Behavior, 14, 330-335.

    McAndrew, F. T., & Perilloux, C. (2012). Is self-sacrificial competitive altruism primarily a male activity? Evolutionary Psychology, 10, 50-66.

    Rusch, H., Leunissen, J. M., & van Vugt, M. (2015). Historical and experimental evidence of sexual selection for war heroism. Evolution and Human Behavior, 36, 367-373.

    Tooby, J. & Cosmides, L. (2010). Groups in mind: The coalitional roots of war and morality. In H. Høgh-Olson (Ed.), Human morality and sociality: Evolutionary & comparative perspectives (pp. 191-234). New York: Palgrave MacMillan.

    Van Vugt, M., David De Cremer, D., & Janssen, D. P. (2007). Gender differences in cooperation and competition: The Male-Warrior Hypothesis.” Psychological Science, 18, 19-23.

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