Major societal collapse can be predicted by early statistical warning signs, according to new research.
The framework, published in the Proceedings of the National Academy of Sciences, uses archaeological evidence from the European Neolithic – a time of immense change that eventually led to widespread social collapse – to forecast when a society is on the brink of breaking down.
According to the paper, at times of great transition, an ecosystem’s resilience begins to wane. This understanding is mostly based on findings from non-human studies and measured using statistical data known as early warning signals, which empirically describe the ability of the ecosystem to adapt to change and recover.
This research team, comprising Sean Downey and Randall Hass from the University of Maryland in the US and Stephen Shennan from University College London in the UK, wanted to apply the model to human-centred environments to see if there was correlation between a population’s decline in resilience, such as emerging illnesses and wars, and eventual social collapse.
“Although regime shifts are well documented in human-dominated ecosystems, the degree to which [early warning signals] anticipate them remains largely unexamined,” say the researchers in their paper.
“To our knowledge, this study is the first to find early warning signals of demographic regime shift among human populations.”
The researchers used archaeological evidence from a period in European history around 9,000 years ago, in which social change was met with significant population decline.
The Neolithic era was a time of great innovation, in which tools and processes were rapidly developed with significant societal impacts. It was during this period that metal tools, writing and the first “urban” areas began to emerge.
The introduction of agriculture led to huge population booms in Europe, which were followed by social instability and collapse.
The researchers examined data from more than 2,000 archaeological sites across nine regions of Neolithic Europe, many of which experienced dramatic boom-bust demographic changes – some populations dropping by 60% in less than a century.
The research team applied two sets of warning signals: critical slowing down and flickering. Critical slowing down reflects the time it takes a population to recover from shocks such as disease, war and famine, while flickering describes the population becoming stuck in particular behaviours or patterns following such a disturbance which can prevent adaptation or progress.
Sure enough, the “resilience” of the population correlated with demographic behaviours in the lead-up to the Neolithic European collapse.
“It is unsurprising that societies on the verge of collapse may exhibit warnings signs; yet it is difficult to demonstrate such phenomena empirically,” the researchers explain.
The researchers say this new framework could be used to measure and predict social change across human demographics, certainly in the past, and possibly into the future, too.
“The results suggest that archaeological information can potentially be used to monitor social and ecological vulnerability in human societies at large spatial and temporal scales.”