Examining US-American soldiers who fought in the conflict, experts from the University of Southampton and universities in Germany and Amsterdam discovered that Medal of Honor recipients fathered more offspring than the regular veterans. From a control sample of 449 regular veterans and 123 surviving Medal of Honor recipients, the team found that Medal of Honor recipients had an average of 3.18 children, while regular veterans averaged 2.72 children.
To find their control sample, the researchers collected biographical data from online obituaries and newspaper articles. The team argues: “This is a valid control group because a majority of the US-American soldiers of WWII were conscribed to conduct their military service in the war (about 61%; Flynn, 1993), and because a large share of all US-American men aged 18–45 at the time served during WWII.”
The researchers also note that “much of the reproductive phase of these soldiers falls within the time before contraceptives became publicly available in the early 1960s”.
Experts supplemented their Second World War analysis with an investigation of 92 women studying in the UK today. The women were presented with hypothetical profiles of the opposite sex, representing varying levels of heroism in different contexts such as warfare, sport and business. They were then asked a series of questions designed to determine how attracted they were to the different profiles.
The study revealed that women were more likely to find a soldier attractive and were more inclined to date him if he had been awarded a medal for bravery in combat. Interestingly, whether or not a non-decorated soldier had seen combat in a warzone or remained in the UK did not have a statistically significant effect on his attractiveness. Displays of heroism in other fields, such as in sports or in business, also had no effect on how likely women were to find them attractive.
In a subsequent experiment, 159 women and 181 men studying in Holland took part in a similar exercise to determine their level of sexual attraction to the opposite sex. This time, the soldier profiles displayed various levels of bravery, either in combat or by helping in a natural disaster zone.
A British soldier says goodbye to his wife and daughter before leaving for France, a fortnight after the outbreak of the Second World War, 20 September 1939. (Photo by James Jarche/Paul Popper/Popperfoto/Getty Images)
Again, heroism in combat increased women’s levels of sexual attraction towards male soldiers, but heroism in a disaster zone had no impact. Female heroes, both in combat and in disaster zones, were deemed less attractive by men than their non-hero counterparts.
The researchers concluded: “War heroism likely benefits men because it increases their sexual attractiveness and as a result, their reproductive success. Our findings suggest that the role of sexual selection must not be ignored in understanding the roots of warfare and why men fight.”
Joost Leunissen, a psychologist at the University of Southampton and co-author of the study, said: “Raids, battles, and ambushes in ancestral environments, and wars in modern environments, may provide an arena for men to signal their physical and psychological strengths. Of course, women may not always witness these heroic acts in person, but such information is likely to be widely communicated within a tribal community, particularly when the actions of male warriors are outstandingly brave.”
Leunissen added: “This [study] provides evidence for the hypothesis that gender differences in intergroup conflict can have an evolutionary origin, as only males seem to benefit from displaying heroism. In light of the physical dangers and reproductive risks involved, participating in intergroup aggression might not generally be a viable reproductive strategy for women.
“Heroism also seems to be a context-specific signal, as it only had an effect on attractiveness in a setting of intergroup conflict. Indeed, soldiers who displayed heroism were only considered to be more attractive when this was displayed in a warfare context and not in another situation which is frequently associated with the army – helping during and after natural disasters.”
The study is published online in the journal Evolution and Human Behaviour. The research team was made up of academics from the University of Southampton; the University of Giessen; the Technical University of Munich, and VU University Amsterdam.