What you do in Starbucks may be linked to more than just your personal coffee preferences. As Science reports, a new study on coffee-shop behavior in different parts of China indicates that farming practices that date back generations still influence how people behave in public. It found that in regions where agriculture traditionally focused on wheat, people were much more likely to be sitting alone at coffee shops compared to people in areas where rice was the dominant crop.

The study, in Science Advances, sounds kind of crazy at first: What my great-grandfather farmed has nothing to do with how I drink my latte, surely. But the design of the study, which involved observing almost 9000 people at 256 coffee shops in six different Chinese cities, is a surprisingly clever way for scientists to observe cultural differences in the real world, researchers who weren't involved in the study told Science.

The study's authors, from the University of Chicago’s business school, Beijing Normal University, and the University of Virginia, wanted to know if the cultural differences of farming wheat and rice persisted through non-farming generations. Rice paddies require twice as much labor as a crop like wheat, as well as massive irrigation systems that would require cooperation between multiple farmers to build and operate. Thomas Talhelm, the study’s lead author, has previously proposed what he calls the "rice theory of culture." That is, the cooperation between neighbors necessary to grow rice led to an interdependent culture that is more collectivist and community-oriented, compared to cultures that grow wheat (like the U.S.), which have developed to be more focused on the individual.

What does this have to do with coffee? The researchers examined how people behave in public in northern China, a wheat-growing region, compared with southern China, a rice-growing region, as a way to examine how cultural differences that arose from agricultural practices still persist in urban life. Across local coffee shops and big chains like Starbucks, they observed that on weekdays, an average 10 percent more people in northern Chinese coffee shops were drinking their coffee alone compared to southern Chinese coffee shops. That number varied by day of the week and time of day, though the researchers didn’t explore why. (Possibly, people just don’t hang out with their friends much in the middle of a Monday morning.) On weekends, the difference was slightly smaller—5 percent—but still significant.

The difference held even when controlling for the type of coffee shop (international chain or local shop), age demographics of the area, and the percentage of workers in the city who are self-employed (and thus, more likely to do their work in a coffee shop).

To further study how regional differences affect behavior, the researchers decided to rearrange some chairs. They went to Starbucks and pushed chairs together in a way that would inconvenience people trying to walk through the cafe, then waited to see how many people would push the chairs out of their way. They found that in a sample of 700 Starbucks customers that were subjected to what they call “the chair trap,” people in wheat-growing areas were more likely to move the chairs out of their way (an individualistic move) while those in rice-growing areas were more likely to adapt themselves to the situation, squeezing their bodies through the tight space without disturbing the chair setup (a collectivist move).

"The fact that these differences appeared among mostly middle-class city people suggests that rice-wheat differences are still alive and well in modern China," the researchers write. This included in Hong Kong, which is located in a rice-growing region but is both wealthier and, due to its time as a British colony, has more Western influence than mainland Chinese cities. In general, the southern cities studied were denser and more developed than Beijing and Shenyang in the north, according to the researchers, and yet economic growth and urbanization didn't seem to make the culture more individualistic.

The researchers have proposed doing a similar study in India, a country that also features a split in wheat- and rice-growing regions. Since China's north-south split means that rice-growing and wheat-growing cities feature significantly different climates, it may be useful to see whether the difference holds in cities in India that share the same climate but have different crops.

[h/t Science]