What Makes a Society More Resilient? Frequent Hardship.

From the Roman Empire to the Maya civilization, history is filled with social collapses. Traditionally, historians have studied these downturns qualitatively, by diving into the twists and turns of individual societies.

But scientists like Philip Riris have taken a broader approach, looking for enduring patterns of human behavior on a vaster scale of time and space. In a study published Wednesday, these methods allowed Dr. Riris and his colleagues to answer a profound question: Why are some societies more resilient than others?

The study, published in the journal Nature, compared 16 societies scattered across the world, in places like the Yukon and the Australian outback. With powerful statistical models, the researchers analyzed 30,000 years of archaeological records, tracing the impact of wars, famines and climate change. They found that going through downturns enabled societies to get through future shocks faster. The more often a society went through them, the more resilient it eventually became.

“Over time, you will suffer less, essentially,” said Dr. Riris, an archaeologist at Bournemouth University in England. “There tends not to be wholesale collapse.”

The researchers tracked the history of societies by taking advantage of the way archaeologists tell time. Most organic material, whether it’s charcoal or mussel shells, contains trace amounts of radioactive carbon-14, which gradually breaks down over thousands of years. By measuring the carbon-14 left at an archaeological site, researchers can estimate its age.

This approach can also track population changes. As human groups get bigger, they burn more wood, eat more food and leave behind more garbage, all of which can be dated. When those groups shrink, their sites become rarer.