Utilizing Physics to Understand Social Systems

Siegenfeld had been studying superconductors and other materials with potentially useful technological properties at the Massachusetts Institute of Technology (MIT).

“It felt like there was just too much of a disconnect between the work I was doing and something that would really have an impact on the world,” he said. “Because I was a Hertz Fellow, I felt I had an obligation to take advantage of the freedom to innovate, otherwise I’m not living up to the trust that was placed in me when I was selected.”

This turning point overlapped with the 2016 Hertz Summer Workshop, where he discussed his concerns with other fellows. Someone suggested the book, "Social Physics," written by a professor in the MIT Media Lab. 

That work turned out not to be the type of research that interested Siegenfeld, but it did plant a seed. “It was the first time I had the idea of, oh, maybe there’s a way that I can apply physics to some of the problems that I’m more interested in, or the things that felt like they’d be more impactful,” he said. 

To Siegenfeld, some of the biggest challenges facing the country, and the ones that called to him most, were of a social nature, including political polarization. He saw studying such issues as fitting with his obligation to help his country in times of crisis. “I take the national defense pledge of the Hertz Foundation very seriously and having a better understanding of such issues seemed like something that’s very important for the country,” he said.

Inspired by various groups applying concepts of physics to social systems, including the New England Complex Systems Institute, where he is currently a postdoc fellow, Siegenfeld began leveraging physics concepts to identify a system’s largest-scale behavior. 

“It’s a theme that comes up a lot in physics called universality—trying to understand the collective properties of systems, even if we don’t understand all of the details,” he said. His work has demonstrated how taking a big-picture view provides a better understanding of societal behavior, including research on how low voter turnout encourages political instability and how that instability leads to negative representation.

When COVID-19 struck, Siegenfeld applied his approach to the pandemic. “Prior to the pandemic, there was a lot of flawed science related to people modeling things in a too formulaic or mechanistic way and not taking a step back and looking at the big picture,” he said. “For instance, the scientific consensus before COVID broke out was that travel restrictions didn’t work. But the research did not consider the effect of social distancing or other non-pharmaceutical interventions. We showed that if you combine travel restrictions with non-pharmaceutical interventions, you can contain pandemics.”

He plans to focus future research on economies. “I’m interested in trying to understand why the free-market models work as well as they do in some cases, and where they are breaking down. Sometimes the models describe the system overall pretty well. From the point of view of a physicist, it’s interesting when the assumptions are wrong at a fine-grained level, but at a large-scale level, they work. Understanding why they do sometimes work is important because it can lead to a better understanding of when they won’t,” he said. 

Siegenfeld credits the Hertz Fellowship with motivating him to pursue his unorthodox research direction. “It was important in the motivation and also then in the execution, providing the financial support and the community support as well,” he said.

This support, along with his Jewish faith, moves him to give back to the Hertz Foundation. Siegenfeld started donating to the foundation the first year he was a fellow and has given every year since. 

“In Jewish tradition, even if you’re a recipient of charity, you’re still obligated to give charity. The foundation giving me money and me giving some of it back—I think symbolically at least there’s something nice about the reciprocity,” he said. 

“Now that I’m drawing a salary, it feels even more important to give back. I am in the position that I am in largely because of the Hertz Foundation. I give because it feels like the right thing to do.”