“Different numbers of men and women trigger a competitive motive, a desire to compete,’’ said Joshua Ackerman, an assistant professor of marketing at the MIT Sloan School of Management and a coauthor of the paper. “The core underlying theme, the evolutionary piece to this, is having different numbers of men and women signals different opportunities for romantic partners,’’
Although, he added, “It’s not that people are consciously thinking this stuff.’’
Sex ratios have been extensively examined by biologists, with studies looking at how different proportions of males and females affect behavior in animals that range from the gray mouse lemur to the European bitterling, a freshwater fish.
Human studies have tended to study gender imbalance and its effect on behaviors such as aggression. But in the new study, the researchers gathered data from 134 US cities, including the sex ratios of unmarried people, average consumer debt, and the number of credit cards per person.
The researchers found that in cities that had more unmarried men than women, there tended to be greater average personal debt and more credit cards per person.
This overall trend, however, was just a correlation and did not suggest a male-female imbalance played a causal role - or rule out other explanations for the differences in debt.
The average debt level and number of credit cards were not broken down by sex, making it impossible to know the specific role single men were playing in the trend. So the researchers conducted a set of laboratory experiments to try and pinpoint the possible origins of the financial differences.
They used various means to prime research participants with the sense they were in an environment dominated by either men or women.
