People often panic over rare but dramatic disasters like plane crashes, terror attacks, or nuclear accidents—while ignoring more common dangers such as car crashes or heart disease.
Scientists have long wondered why humans react so strongly to these low-probability but high-impact events.
Now, researchers from the Universities of Exeter and Bristol believe they’ve found an evolutionary reason.
In a new study published in Scientific Reports, the team used mathematical modeling to show that our so-called “dread risk” response may have evolved to protect our families and genetic survival.
Their model suggests that people who instinctively avoid situations that could wipe out a large portion of their community or extended family—no matter how unlikely—are more likely to pass on their genes over time than those who take such risks more calmly.
This means that what looks like irrational behavior today may have once been an adaptive survival strategy.
For example, avoiding a rare but catastrophic event such as a volcanic eruption or tribal massacre would have helped safeguard one’s relatives and ensure the continuation of shared genes. Over generations, this strong emotional bias—felt as dread—became ingrained in human psychology.
Dr. Sasha Dall, Associate Professor of Theoretical Biology at the University of Exeter, explained, “The world has always been full of danger and uncertainty.
Although modern life is much safer, we’ve retained a deep-seated fear of events that could cause mass death. This fear shapes our decisions, even when the actual risk is tiny.”
The study also helps explain puzzling modern behavior. After the 9/11 terrorist attacks, for instance, many people in the U.S. avoided flying.
As a result, road travel increased, leading to about 3,000 additional deaths from traffic accidents in the following 18 months. From a purely statistical point of view, this choice was more dangerous—but from an evolutionary standpoint, it made emotional sense.
Lead author Emeritus Professor John McNamara from the University of Bristol said that this dread response is not just fear—it’s a built-in defense mechanism. “It doesn’t matter how well-informed people are,” he said. “We seem to have evolved a natural bias against rare but catastrophic risks. This bias, which we feel as dread, acts to protect our extended families and our genetic lineage.”
In short, our dread of rare disasters may be a deeply rooted survival instinct. Even if it leads us to make riskier day-to-day choices, it once served a vital role: protecting our ancestors—and their genes—from extinction.
