Our ancestors didn't shop for holiday gifts, but the way we buy may owe credit to thousands of years of evolution.
In a new study, researchers propose that our mall-visiting behaviors harken back to the days when men hunted and women foraged.
Modern men, for example, generally want to get into a store and get right back out -- just like their hunting forefathers wanted to find and bring meat home as quickly as possible. On the other hand, women get back to their foraging roots by sorting through racks of sweaters on sale -- as if scanning plants for signs of ripeness.
Plenty of people defy these general trends, of course, but the findings might help men and women better understand each other and limit arguments that surround shopping, said lead author Daniel Kruger, an evolutionary psychologist at the University of Michigan School of Public Health in Ann Arbor, Mich.
His new theory could also help marketers design better stores that cater to gender differences.
"Women would want to have more things to search through and to be able to experience them, touch them, feel textures and see colors," Kruger said. "With a guy, he knows the properties he wants. It may be more efficient to have a counter that the guy walks up to, says what he wants, and they go get that item from a storage room."
The idea for Kruger's new study arose from a personal experience. He and his now-wife were traveling with friends through the Czech Republic. When they arrived in Prague, the women immediately wanted to go shopping, an impulse that the men did not understand.
"We thought, 'Why do you want to go shopping? You can go shopping anywhere. There's a thousand years of culture here,'" he said. "They were adamant. They put their foots down. They took the credit cards and left."
That wasn't the end of it. When the women returned, Kruger said, they were full of joy and pride as they showed off their loot, even though many of their purchases came from a chain store that had outlets in other countries.
"For them," he said, "It was just the thrill of the chase."
In his new study, Kruger surveyed more than 450 college students about their shopping habits. Participants ranked their level of agreement to statements on a scale from 0 to 100.
Statements included "I can usually find my way around an unfamiliar store because I know what types of products are usually near each other;" "I sometimes remember an expensive item that I like, and go back when I know the store is having a big sale;" and one that Kruger couldn't resist: "If I was on vacation in a foreign country, I would make sure to check out their stores."
The results fell into the gendered trends that Kruger was expecting to find: Overall women tended to behave like foragers, and men acted like hunters. To him, that made sense.
When groups of hunter-gatherers arrived in a new place, he said, the women were eager to scope out the landscape for patches of food that they would return to again and again. Foraging was a daily and social activity, and kids often came along.
To determine whether a plant was perfectly ripe, women developed a fine attention to colors, shapes, sizes, textures and smells. All of those senses come into play when trying to find shoes that match a new dress or clothes to buy as gifts.
Seasonality was also an important part of gathering, as different foods become ripe at different times of year. The modern equivalent, Kruger speculated, are seasonal sales.
"When women go into a store and see a $200 sweater they like, but they don't want to pay that much, they are going to save it in their memories and go back to that store later," Kruger said. "When a guy has something specific in mind, he wants to go in, get it, and get out."
For men, any deer was a good deer. Any meat was good meat.
"The idea that men are more motivated to hunt mobile prey over long distances suggests that the design of retail stores and shopping malls doesn't give males enough of a challenge to make things interesting," said Geoffrey Miller, an evolutionary psychologist at the University of New Mexico, in Albuquerque and author of the book Spent: Sex, Evolution, and Consumer Behavior. "Tracking down resistant prey is an exciting thing to a male consumer."
Human behavioral ecologist Rebecca Bird had a different reaction to the new study.
"I think it's ridiculous and naive to assume that there's a gene for vegetable procurement" or for navigation through a mall, said Bird, of Stanford University in California. Context is far more important, she said, "because humans are ecologically general creatures."