Griskevicius and colleagues found a significant link between sex ratio and credit card debt.
So at a glance it's hard to explain why the people of Columbus have, on average, consumer debt that's roughly ,500 more per capita than the people of Macon.
A group of psychologists thinks the disparities may have something to do with the fact that these two cities have widely diverging sex ratios.
The cities of Macon and Columbus, in Georgia, have a lot in common.
Sex ratio appears to influence behavior by increasing the intensity of same-sex competition for mates.
Accordingly, a scarcity of women led people to expect men to spend more money during courtship, such as by paying more for engagement rings.