A new study shows that when women are scarce, they expect men to spend more on engagement rings.
Men are known to go to great lengths—and great expense—to impress women. This is most obviously the case when the male population outnumbers that of females, and laws of supply and demand kick in.
A new report from the University of Minnesota’s Carlson School of Management finds that men are prone to spend more, save less, and even be willing to go into debt when they believe women are scarce in their neck of the woods:
“What we see in other animals is that when females are scarce, males become more competitive. They compete more for access to mates,” says Vladas Griskevicius, an assistant professor of marketing at the Carlson School and lead author of the study. “How do humans compete for access to mates? What you find across cultures is that men often do it through money, through status and through products.”
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In the study, entitled “The Financial Consequences of Too Many Men: Sex Ratio Effects on Savings, Borrowing, and Spending” and set to be published next month in the Journal of Personality and Social Psychology, volunteers read stories indicating that the local population had either more men or more women. Then, they were asked how much money they’d save each month from their paycheck, and how much they’d be likely to spend using credit cards when they don’t have enough cash for immediate expenditures.
Men, it seems, turn into spendthrifts when women are in short supply. When women are scarce, savings rates for guys drop 42%, and dudes say they’re willing to borrow 84% more each month via credit cards.
For a real-life example of this phenomenon, USA Today points to a pair of communities in Georgia:
In Columbus, Ga., where there are 1.18 single men for every single woman, the average consumer debt was $3,479 higher than it was 100 miles away in Macon, Ga., where there were 0.78 single men for every woman.
The study indicates that the ratio of the sexes isn’t likely to affect how women spend money. But it does have an impact on women’s expectations regarding how much cash a guy will spend to woo the ladies. When women hear that guys outnumber girls, they expect men to drop more money on dates, Valentine’s gifts, and engagement rings. Griskevicius, the report’s lead author, explains that women know that being outnumbered puts them in the driver’s seat:
“When there’s a scarcity of women, women felt men should go out of their way to court them.”
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I’d love to see how varying sex ratios change the likelihood of how often men and women go to the gym.
Brad Tuttle is a reporter at TIME. Find him on Twitter at @bradrtuttle. You can also continue the discussion on TIME’s Facebook page and on Twitter at @TIME.