For centuries, historians have debated whether the “Great Fear” panic in the early days of the French Revolution was driven by the mass hysteria of ignorant peasants or a rational response to the famine and economic conditions of the day.

To figure it out, Italian researchers applied modern-day tools of epidemiology to trace how the rumors that provoked the upheaval spread across France.

The findings, published in the journal Nature, could offer insights into how unrest erupts today—for example, the recent “Block Everything” protests occurring across France in opposition to public-spending cuts.

In the summer of 1789, French peasants formed militias to combat bandits rumored to be attacking towns and villages, destroying crops and terrorizing peasants. When the brigands, which were believed to be acting with the support of nobles, didn’t materialize, the peasants turned against castles to destroy land titles held by local lords.

The rumors, they found, were more likely to affect towns and cities with more-educated populations, rather than small villages with less-educated residents, according to Stefano Zapperi, a physics professor at the University of Milan and an author on the study. In addition, regions with high wheat prices—and hence higher food prices—were more likely to be “infected.”

Although the rumors of bandit attacks were false, the Great Fear spread according to a logical pattern linked to the social and political conditions of the time, the study’s authors said.

“Cities or areas that had suffered most had more incentive to revolt, in this sense, because the conditions were harsher,” Zapperi said.

The wave of unrest and the French Revolution ended the medieval landholding system of feudalism and changed the nation’s political system. The monarchy was removed.

“The Great Fear can also be seen as a reaction to perceived threats, especially to grain and property, rather than to real brigandage,” the authors wrote.

Geographical and physical proximity were important for the Great Fear to spread from town to town by horseback, the authors said.

Today, you don’t need a horse.

Social unrest and panic can be accelerated through social media, according to Brian Uzzi, professor of leadership at Northwestern University. He has studied mob psychology and how social unrest spreads in the U.S.

“Social media is considered a facilitator or a catalyst,” Uzzi said. “It spreads content, but it also spreads emotions, and emotions are contagious.”