A new study from Dartmouth College explores how fear, social influence, and personal decision-making have contributed to the United States becoming one of the most heavily armed countries in the world. Researchers say the nation now has approximately 120 firearms for every 100 people, a level of civilian gun ownership unmatched globally. The study examines why individuals continue purchasing firearms even when widespread gun ownership may ultimately reduce overall public safety.

Published in Science Advances, the research introduces the concept of “overarming,” a situation in which the social costs of widespread firearm ownership outweigh the personal benefits individuals believe they gain from owning guns. According to the researchers, people often buy firearms because they believe doing so will increase their personal security. However, when many people make the same decision, society as a whole may become more dangerous rather than safer.

To better understand this behaviour, the research team developed a mathematical model based on evolutionary game theory, a method used to study how individual decisions shape collective outcomes. The model examined how social factors influence a person’s decision to buy a firearm and how those choices affect the decisions of others within the same community or social network. The findings suggest that as more people arm themselves, others increasingly perceive the world around them as threatening and feel pressured to buy firearms for protection. This creates a self-reinforcing cycle in which fear encourages gun purchases, and rising gun ownership further intensifies fear.

“Our work is not an argument against guns,” said Feng Fu, associate professor of mathematics and the study’s corresponding author. “There are benefits to firearm ownership, and we find that a socially optimal level of ownership may be greater than zero. The problem is systematic overarming, which creates a disconnect between individual interests and the well-being of society.” Fu added that the gap between personal decisions and broader social outcomes is not merely theoretical, noting that higher gun ownership rates are consistently associated with higher rates of gun-related deaths.

The researchers tested their model using firearm sales data collected during the COVID-19 pandemic, a period that saw the highest gun sales in American history. Concerns about personal safety, social unrest, political instability, and uncertainty about the future led many Americans to purchase firearms. The team observed what they described as an arming-and-fear feedback loop, where increasing gun ownership caused more people to feel unsafe, which in turn encouraged even more gun purchases. Co-author Daniel Rockmore explained that as more people arm themselves, others begin to view the world as increasingly dangerous, making firearm ownership appear necessary for self-protection.

Co-author Michael Herron compared the phenomenon to the Cold War doctrine of mutually assured destruction, in which competing sides continue stockpiling weapons because neither wants to risk being less prepared than the other. Similarly, individuals may continue arming themselves because they fear being the only unarmed person in a confrontation. The researchers also studied real-world social networks, including gang networks in Montreal, rural communities in Honduras, and social ties on an American university campus. They found that social networks can either amplify fear or help reduce it. The team suggests that stronger community connections, along with public information campaigns that help people more accurately assess real risks, may help break the cycle of fear-driven gun ownership and reduce overarming over time.

More information: Feng Fu et al, Bivalent Impact of Social Networks on Overarming: Model-Based Insights on the Alignment between Social and Individual Interests, Science Advances. DOI: 10.1126/sciadv.aed3904

Journal information: Science Advances Provided by Dartmouth College