This’ll be a conundrum for everyone if the effect is large enough to matter. NewScientist (8 October 2016) reports on an unexpected result of imprisoning criminals for sex crimes:
In areas where men outnumber women, there were lower rates of murders and assaults as well as fewer sex-related crimes, including rapes, sex offences and prostitution. Conversely, higher rates of these crimes occurred in areas where there were more women than men.
Ryan Schacht at the University of Utah in Salt Lake City and his colleagues analysed sex-ratio data from 3082 US counties, provided by the US Census Bureau in 2010. They compared this with crime data for the same year, issued by the US Federal Bureau of Investigation. They only included information about women and men of reproductive age.
For all five types of offence analysed, rising proportions of men in a county correlated with fewer crimes – even when accounting for other potential contributing factors such as poverty. The results suggest that current policies aimed at defusing violence and crime by reducing the amount of men in male-dominated areas may backfire (Human Nature, doi.org/brbb).
When women are in short supply, men perceive them as being a more valuable resource, says Schacht. Consequently, men must be more dutiful to win and retain a female partner. In an abundance of women, men are spoilt for choice and adopt promiscuous behaviour that brings them into conflict with other men, and makes them more likely to commit sex-related offences.
This has unsettling implications for the motivations for men to be non-violent, turning it from a principled, or lack, stand, to a cold-blooded market-based assessment of the risks of crime. Even divorce rates rise as men disappear into prison. The original study adds this conclusion:
In addition, although public concern over male-biased sex ratios elevating the risk for female trafficking and prostitution has risen, supporting data are lacking. In China, areas with male excess are not associated with elevated numbers of sex workers (Hesketh et al. 2005). Moreover, sexually transmitted disease rates are lowest in male-biased populations (South and Trent 2010). These trends corroborate our finding that rates of prostitution/commercial vice, which serve as a proxy for uncommitted sexual behavior, are lowest in counties where men are most abundant.
I think what bothers me the most is that, once the core principles of a person have been ascertained, predicting their behavior becomes plausible. But evaluating a market for the number of potential mates? Even if such numbers are available, neither sex is likely to track them down and use them to modulate their behavior; this makes predicting the behavior of your fellows much more difficult.
