When women are few, men spend more

When men outnumber women, men spend more money -- and women expect them to do so.

Those are the conclusions of recent research at the University of Minnesota. Also, a perceived lack of potential mates causes men to save less, borrow more money and do more impulse buying.

According to the study, titled "The Financial Consequences of Too Many Men" (.pdf file), participants were asked to read news articles that indicated that their local populations had more women or more men, then answer questions about saving, borrowing and spending. Male participants who were led to believe that men outnumbered women in their area indicated they would save 42% less and would be willing to borrow 84% more money than the men who thought women outnumbered men.

The results, which are being published this month in the Journal of Personality and Social Psychology, show that humans are not all that removed from animals, according to Vladas Griskevicius, the lead author of the study and a professor of marketing at the university's Carlson School of Management.

"What we see in other animals is that when females are scarce, males become more competitive. They compete more for access to mates," Griskevicius said. In humans, the competition is financial, he said: "What you find across cultures is that men often do it through money, through status and through products."

Research and population data

Researchers also showed participants photo arrays of men and women with different gender ratios. Next, participants were asked to choose between receiving $20 the next day or $30 a month later. When the photos showed men outnumbering women, male participants were much more likely to take the fast cash. Post continues below.

To further test their theories, researchers studied population data and calculated the gender ratios of more than 120 cities. Those with an abundance of single men showed greater ownership of credit cards and had higher debt levels, according to a university news release:

One striking example was found in two communities located less than 100 miles apart. 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 in Macon, Ga., where there were 0.78 single men for every woman.

The impact on women
The study found that perceived gender ratios did not impact women's spending decisions, but they did alter their expectations. Women who read an article that suggested men outnumbered women expected men to spend more money on dates and gifts.

"When there's a scarcity of women, women felt men should go out of their way to court them," Griskevicius said.

The financial behavior studies dealt with perceived gender disparities, but population data indicate that men do outnumber women in some U.S. cities and in certain age ranges.

The 2010 U.S. Census found that there were 11 unmarried men for every 10 unmarried women ages 15 to 49, USA Today reported, noting that ratios varied around the country, with cities such as Birmingham, Ala., and Peoria, Ill., having more women, while Denver and Las Vegas had more men.

That ratio may be a positive for the Vegas casinos, Griskevicius told USA Today: "Having more men than women might fuel gambling behavior."

And if women like big spenders, as the study indicated, then everyone might win.

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• Female graduates earn 17% less than men
• Busting 5 myths about women and money
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• Interactive chart: Finances by age, income