A researcher checks out carefully placed chairs in a Chinese Starbucks prior to watching whether employees and customers will move the chairs, signalling individuality, or squeeze through, indicative of collectivism. Thomas Talhelm.

Northern China has grown wheat and millet for thousands of years, while southern China has grown rice. The time when most of the population was involved in agriculture is long past, but the type of crop grown affects the culture so strongly, researchers have claimed that even urban residents behave differently depending on their home region's crop. Specifically, wheat farming encourages a more individualistic culture than rice, and this manifests in everyday behaviors.

Wheat farming is usually practiced as a relatively solitary activity, with each farm operating independently. Paddy rice requires irrigation systems that encourage farmers to cooperate. Chinese rice farmers are also more inclined to share labor than wheat farmers, working together to plant and harvest each other's crops.

These practices seeped into the culture of the regions, argues Dr Thomas Talhelm of the University of Chicago, and affected even non-farmers. To test this theory, Talhelm, Dr Xuemin Zhang of Beijing Normal University, and the University of Virginia's Professor Shigehiro Oishi watched people in 256 chain stores (chosen for their uniformity) in six Chinese cities (including Hong Kong).

Transporting rice seedlings is labor intensive, so even before collectivisation, it was a much more collaborative process than wheat farming. Thomas Talhelm

Based on a sample size of almost 9,000 people, Talhelm reports in Science Advances that people in rice-growing regions were less likely to sit alone than those in cities where the local crop is wheat. Likewise, when the researchers moved chairs to block the aisle in the same coffee shops, responses differed by region.