Sex Ratio & Spending

Sex Ratio & Spending Photo Credit: Clipart.com

The perception that women are scarce may make men less careful with their money.


The cost of a female shortage. I’m Bob Hirshon and this is Science Update.

When women seem scarce, men may become financially impulsive. This according to University of Minnesota marketing professor Vladas Griskevicius. He was inspired by animal studies, which show that males get more competitive when females are in high demand.

And so in one of the studies, we showed men and women photo arrays. And the photos had either more men than women or more women than men.

Men who saw the male-heavy arrays estimated that they would save less and borrow more in a mock budget. They were also more likely to take a small cash payment immediately than a bigger one later on. Neither pattern showed up in female subjects. And in a separate analysis, the researchers found that cities with more single men than single women have higher consumer debt, and more credit card ownership, than female-skewed cities. I’m Bob Hirshon for AAAS, the Science Society.

Making Sense of the Research

This may seem like a strange study, but it's based on widely observed behavioral patterns in animals. In many species, when females are in short supply, males become more competitive and/or aggressive, often taking bigger risks to attract female attention. Griskevicius thought this might apply to humans as well. But how to find out?

One of his experiments was conducted with volunteers in a lab. It's possible that these people came into the room with certain preconceptions about the ratio of men to women in their community, but it would be hard to determine what they were and how strong they were, since it's not something most people think about on a daily basis. So the researchers decided to create an immediate impression of male/female ratios. To do it, they simply showed the subjects photo collections of individual men and women, some with more men than women, and others with more women than men. They didn't explain why they were showing them—they just wanted to subconsciously suggest that females were either plentiful or scarce.

After viewing the arrays, the volunteers answered some questions about planning an imaginary budget. Remarkably, men who had seen male-heavy photo collections put more money toward spending and less toward savings than men who had seen predominately female photos. Men who had seen fewer female faces also were more likely to accept a $5 cash payoff immediately, rather than wait a month to get a $10 payoff in the mail. 

Women, on the other hand, weren't affected by the photos in these ways. That supports the idea that perceived sex ratios specifically affect male risk-taking. However, the photos did affect female subjects in another way: When asked how much money men should spend on a date or gifts, women who saw predominately male photos made higher estimates than those who saw female-heavy photo collections. In other words, the women seemed to expect that men would be more competitive if there were more men around.

Again, none of the volunteers knew the photos had anything to do with the questions they were later asked. It's striking that just seeing photos in a lab setting would be enough to trigger an effect on their judgment. One could easily imagine that it would take days, weeks, or months for a lopsided sex ratio to sink in. These results suggest that the mere perception of a favorable or unfavorable sex ratio could change people's behavior and expectations immediately. 

But does it? After all, this is a very artificial situation, and the volunteers were just answering hypothetical questions. That's why it's important that the researchers also analyzed data from the real world. And they did find trends that support their findings: namely, that towns with more men than women have higher consumer debt levels and more credit card ownership than towns with more women than men. That doesn't prove anything in and of itself, but it's a pattern you'd expect to find in the overall population, if men's spending were influenced by the perception of available women but not vice versa. 

Now try and answer these questions:

  1. Why did the researchers conduct this study?
  2. How were the men affected by the ratio of men to women in the photos? How were women affected?
  3. How do the lab study and the analysis of spending data complement each other?
  4. Suppose they had only analyzed consumer spending. What other explanations could there be for higher credit card debt in male-heavy areas?
You may want to check out these related podcasts:

For more about sex and behavior in humans and animals, see the Science Update Promiscuous FinchesLizard MatesTestosterone Tradeoff, and Testosterone and Fatherhood.

The Science Update Popularity and Bullying looks at the relationship between adolescent aggression and social popularity.

Going Further

For Educators

For more about sex and behavior in humans and animals, see the Science Update lessons Promiscuous Finches, Lizard Mates, Testosterone Tradeoff, and Testosterone and Fatherhood.

The Science Update Popularity and Bullying looks at the relationship between adolescent aggression and social popularity.

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