That is the result of a study published Thursday in Science comparing people from different parts of China. Researchers led by Thomas Talhelm of the University of Virginia, Charlottesville, found that people from rice-growing regions think in more interdependent and holistic ways than do those from wheat-growing areas.

Talhelm thinks these differences arose because it takes much more cooperation and overall effort to grow rice than wheat. To successfully plant and harvest rice, farmers must work together to build complex irrigation systems and set up labor exchanges. Over time, this need for teamwork fosters an interdependent and collectivist psychology. Wheat, however, can be grown independently, so wheat farmers become more individualistic.

Talhelm found that even people from adjacent counties on