Across the animal kingdom, males are competitive when females are scarce. Now a study with people has examined how the number of women affects men’s attitudes about a marker for competitive fitness: Money. Basically, the fewer the women, the more the men threw their money around. The research is in the Journal of Personality and Social Psychology.

Study subjects read prepared articles that described their local population as being predominantly male or being half male-half female. Then they were asked how much money they’d save and how much they’d spend using credit cards each month. When the men believed there were fewer women, they predicted they’d save 42 percent less money and were willing to spend 84 percent more on credit cards than when the sexes were at equal numbers.  

Participants also looked at photos of groups where the gender ratios were either varied or balanced. Men who were led to believe that women were scarce were more likely to take a $20 gift today than wait for $30 in a month.

Population data supports the experimental findings: In communities with few single women, single men have more credit cards and owe more money. They clearly think that if you wanna play, you gotta pay.

—Christie Nicholson

[The above text is a transcript of this podcast.]