Contrary to what many people may expect, men are actually less violent and much better behaved when in each other’s company than when outnumbered by women, according to a study published last week in the journal Human Nature.

The study authors set out to investigate the assumption that societies with more men than women would suffer from “elevated levels of aggression driven by a glut of testosterone-fueled, unmarried men.” However, somewhat surprisingly, they found the exact opposite to be true, discovering that violent crime committed by males actually rises when women are in the numerical ascendancy.

To conduct their investigation, the researchers used data from the 2010 US Census to determine the sex ratio in each of the country’s 3,082 counties. They then cross-referenced this with figures obtained from the FBI in order to examine how these ratios correlated with levels of violent crimes between men – such as murders and assaults – and sexual crimes like rape, prostitution, and other sexual offenses.

“We find rates of homicide, aggravated assault, rape, sex offenses, and prostitution/commercial vice to be more common in counties with more women than men,” explain the authors, adding that “counties with more men have lower rates of crime and violent behavior.” These findings, they say, “challenge conventional claims of male excess leading to elevated levels of violence.”

Using “mating market theory,” the team explain these results by suggesting that violence should not be considered an inherent characteristic of “maleness,” but is instead used only when doing so brings “reproductive payoffs”.

For instance, they claim that in societies in which women are rare, men who are lucky enough to have a wife or girlfriend have to invest more in their relationships in order to hold on to their partners, and are therefore more likely to settle down and live a family life.

In contrast, when women are more abundant, this theory states that men are likely to act more promiscuously and therefore come into regular competition with each other over females, often leading to violence.

The researchers say their findings are supported by the existing literature on the subject, with studies revealing that prostitution and trafficking of women in China tend to be less common in areas where men outnumber women.

Expanding on their results, the study authors warn against “'tough on crime' policies in highly policed areas of the United States,” where soaring rates of male incarceration are skewing population ratios, resulting in female-dominated communities and potentially encouraging the very sorts of violence these policies are supposedly trying to combat.