Farming methods may explain the psychological differences between East and West, a study has found.

Scientists have long wondered why people living in the US, Europe, China and other countries in Eastern Asia are so culturally far apart. While Westerners are known for their individualism and analytical thinking, eastern culture tends to be interdependent and holistic.

Theories explaining the differences have included wealth and education fuelling individualism in the West, and high rates of infectious disease in the East causing people to be wary of outsiders and more collectivists.

But the real reason may simply be the way people at both ends of the world cultivate rice and wheat, say the scientists.

Paddy rice cannot be grown without ample supplies of water, forcing neighbours to work together to irrigate their crops. It is also highly labour-intensive, requiring about twice the number of hours from planting to harvest as does wheat.

Wheat farmers, in contrast, can rely on the rain and operate much more independently.

To test their theory, the scientists assessed known measures of individualism and collectivism in 1,000 people from different regions of China where rice and wheat are grown.

It’s easy to think of China as a single culture but we found that China has very distinct northern and southern psychological cultures

The results, published in the journal Science, showed distinct psychological differences that mirrored those between the East and West.

Lead researcher Thomas Talhelm, from the University of Virginia, US, said: “It’s easy to think of China as a single culture but we found that China has very distinct northern and southern psychological cultures and that southern China’s history of rice farming can explain why people in southern China are more interdependent than people in the wheat-growing north.

“The data suggests that legacies of farming are continuing to affect people in the modern world.”