Growing rice is hard work. Many people must work together to maintain communal irrigation canals, and transplanting and harvesting are also labour-intensive. By contrast, while rain-fed wheat produces less food per hectare, it needs less labour. A family can support itself growing wheat, while paddy rice literally takes a village.

It has long been suggested that China’s reliance on rice fostered collectivist attitudes, and the Confucian emphasis on group allegiance and conformity. Such attitudes are even cited as explaining why Europe, rather than China, was the home of the industrial revolution: the revolution was based on scientific thinking, which is held to rely on individualism and openness to innovation. But the idea that growing rice promotes a group mentality remained speculation.

Talhelm and his colleagues in China decided to test it. They gave standard tests for cognitive style, individualism, and in-group loyalty to 1162 students in six cities across China, in wheat or rice-growing areas. All were Han Chinese, China’s dominant ethnic group, so other differences were hopefully minimal.