K EL LO G G IN S IGH T
MURAT IY IGUN, NATHAN NUNN AND N A N CY QI A N
B AS E D O N T HE R ESEA R CH OF
When Potatoes Brought Peace In the 16th century, the potato arrived in Europe. The consequences went far beyond diet.
Illust rat io ns b y L i sa Röpe r
The potato, small and humble though it may be, has played an outsized role in history. Many scholars credit the hardy and nutrient-rich crop with rapid population growth across Europe and the rise of industrialization and empires in the West. Now the potato can add a new line to its already fascinating resume: peacemaker. Research from Nancy Qian, a professor of managerial economics and decision sciences at the Kellogg School, finds that potatoes, and the permanent boost in agricultural productivity they brought about, reduced armed conflict in the 18th and 19th centuries. Qian and her two coauthors examined battles in Europe, North Africa and the Middle East between 1400 and 1900 – a notoriously bloody and brutal period. “Everyone was fighting everyone, all the time,” she says. 6
But things changed when Spanish explorers brought back the potato from South America in the 16th century, her study shows. Suddenly, a family of four could grow enough food to survive on about a third as much land as they needed before. This abrupt change in the food supply prompted battle-hardened Europeans to put down their weapons. Qian cannot say for sure exactly why people swapped the sword for the spud, but she has a strong suspicion. “Historically, agricultural land was the most valuable resource,” she explains. “If the land is able to produce more food per area, then it becomes cheaper – and if it’s cheaper, then it’s less valuable, and people don’t want to fight over it as much.” In a 2011 paper, Qian and coauthor Nathan Nunn at Harvard found that potatoes were responsible for a significant portion of the increase in population and urbanization that took place in
KELLOGG SPRING/SUMMER 2018