Could what we eat shape how we think? A new paper in the journal Science by Thomas Talhelm at the University of Virginia and colleagues suggests that agriculture may shape psychology. A bread culture may think differently than a rice-bowl society.

Chris Silas Neal




Psychologists have long known that different cultures tend to think differently. In China and Japan, people think more communally, in terms of relationships. By contrast, people are more individualistic in what psychologist Joseph Henrich, in commenting on the new paper, calls "WEIRD cultures."
WEIRD stands for Western, educated, industrialized, rich and democratic. Dr. Henrich's point is that cultures like these are actually a tiny minority of all human societies, both geographically and historically. But almost all psychologists study only these WEIRD folks.
The differences show up in surprisingly varied ways. Suppose I were to ask you to draw a graph of your social network, with you and your friends represented as circles attached by lines. Americans make their own circle a quarter-inch larger than their friends' circles. In Japan, people make their own circle a bit smaller than the others.
Or you can ask people how much they would reward the honesty of a friend or a stranger and how much they would punish their dishonesty. Most Easterners tend to say they would reward a friend more than a stranger and punish a friend less; Westerners treat friends and strangers more equally.
These differences show up even in tests that have nothing to do with social relationships. You can give people a "Which of these things belongs together?" problem, like the old "Sesame Street" song. Say you see a picture of a dog, a rabbit and a carrot. Westerners tend to say the dog and the rabbit go together because they're both animals—they're in the same category. Easterners are more likely to say that the rabbit and the carrot go together—because rabbits eat carrots.
None of these questions has a right answer, of course. So why have people in different parts of the world developed such different thinking styles?
You might think that modern, industrial cultures would naturally develop more individualism than agricultural ones. But another possibility is that the kind of agriculture matters. Rice farming, in particular, demands a great deal of coordinated labor. To manage a rice paddy, a whole village has to cooperate and coordinate irrigation systems. By contrast, a single family can grow wheat.
Dr. Talhelm and colleagues used an ingenious design to test these possibilities. They looked at rice-growing and wheat-growing regions within China. (The people in these areas had the same language, history and traditions; they just grew different crops.) Then they gave people the psychological tests I just described. The people in wheat-growing areas looked more like WEIRD Westerners, but the rice growers showed the more classically Eastern communal and relational patterns. Most of the people they tested didn't actually grow rice or wheat themselves, but the cultural traditions of rice or wheat seemed to influence their thinking.
This agricultural difference predicted the psychological differences better than modernization did. Even industrialized parts of China with a rice-growing history showed the more communal thinking pattern.
The researchers also looked at two measures of what people do outside the lab: divorces and patents for new inventions. Conflict-averse communal cultures tend to have fewer divorces than individualistic ones, but they also create fewer individual innovations. Once again, wheat-growing areas looked more "WEIRD" than rice-growing ones.
In fact, Dr. Henrich suggests that rice–growing may have led to the psychological differences, which in turn may have sparked modernization. Aliens from outer space looking at the Earth in the year 1000 would never have bet that barbarian Northern Europe would become industrialized before civilized Asia. And they would surely never have guessed that eating sandwiches instead of stir-fry might make the difference.

http://online.wsj.com/articles/can-w...res-1401489355