A study of the effect of sex ratios by American county has found places with more men, relative to women, have fewer single men. Confusingly, it is where women outnumber men that men are most likely to be unpartnered. The finding is not just counterintuitive, but challenges past research on excess men and social unrest. The implications could be significant for countries with emerging male majorities.
Most crime, particularly violent crime, is committed by men. Moreover, many studies have indicated that single men are particularly likely to be culpable, since forming a relationship and having children reduces the propensity for risk-taking, including violence. It’s only to be expected, therefore, that locations with a lot of unattached men, including those where men drastically outnumber women, will be unusually violent. Frontier societies, including the “Wild West”, have done nothing to dispel this notion.
Female infanticide and sex-selective abortion are creating heavily skewed sex ratios across much of Asia. There are plenty of reasons to be appalled by this, but fear of what the surplus of men will do to crime rates and social stability has attracted much of the attention.
University of Utah anthropologists Dr Ryan Schacht and Dr Karen Kramer have challenged this theory in PLOS One. They claim that where women are scarce, heterosexual men are more likely to form long-term relationships, which should then lead to decreased socially undesirable activity. Presumably, knowing that their odds on the dating market aren’t good, men in these environments prefer stability to being footloose and fancy free.
It is where women outnumber men that fewer stable heterosexual couples form, possibly because the straight men figure they’ve got it made and don’t need to settle down unless they really want to.
"If you are the relatively rare sex, you can be more demanding of a potential partner," Schacht said in a statement. "You can be choosier, and of the partner you choose, you can be more demanding of what you want in a relationship."
Schacht developed the hypothesis that sex ratios alter men's enthusiasm for long-term relationships as part of his doctoral studies. He interviewed more than 300 people in eight villages in Guyana. Migration had left some of these villages with substantially more women and others with more men.
Having reported that the men behaved very differently depending on their village's balance, Schacht set out to see if the same was true on a wider scale. The authors used US census data for the ratio of men to women by county and compared this with marriage rates and other measures of family stability. They saw the same pattern as Schacht’s Guyana observations.
Number of men for every 100 women by county. Marriage rates are highest in the blue locations. Ryan Schacht/PLOS One.
The authors argue US census data is more accurate than in some countries with highly skewed sex ratios. Nevertheless, their work is likely to be heavily scrutinized to test if they are mistaking correlation for causation. Factors such as poverty drive both marriage rates and sex ratios. The authors also admit that the pattern they found may break down for particularly extreme ratios.