A Physicist Who Models ISIS and the Alt-Right

Neil Johnson used to study electrons as a buttoned-up professor of physics at the University of Oxford. Then, a decade ago, he decamped to the University of Miami — a young institution that he sees as unconstrained by rigid traditions or barriers between disciplines — and branched out. In recent years, the 55-year-old physicist has published research on financial markets, crowds, superconductivity, earthquake forecasting, light-matter interactions, bacterial photosynthesis, quantum information and computation, neuron firing patterns, heart attacks, tumor growth, contagion and urban disasters, not to mention his extensive body of work on terrorism and other forms of insurgent conflict.

Johnson models the extreme events and behaviors that can arise in complex systems. The author of two books on complexity, he has found that the same principles often apply, regardless of whether a system consists of interacting electrons, humans or anything else. After the terrorist attacks of Sept. 11, 2001, he began modeling extremism in human society. He had also spent time in Colombia during the war against the FARC guerrilla army, and grew up near London during the era of IRA bombings. “I started wondering what the patterns of attacks in the respective places might be telling us about how humans do terrorism,” he said. “Terrorism suddenly became, for me, an urgent problem that I might be able to help society understand, and perhaps even one day predict.”

The rise of ISIS has served as both an impetus and test case for Johnson’s models. Even more recently, he has begun using his models to study the growth of white nationalist groups in the United States.

Quanta Magazine caught up with Johnson to discuss his findings by phone in June, before he left to spend the summer working with collaborators in Bogota, Colombia. A condensed and edited version of that conversation, and a subsequent email exchange after the events in Charlottesville, follows.

What’s a physicist doing studying terrorist networks, financial markets and all these other systems?

In all these complex systems, the pieces of the system interact with each other and they evolve over time. And there’s something that a collection of objects like that can do which a handful of coins cannot do. I can throw up a set of coins and it would always come down pretty much 50-50 heads and tails, and there will be a little bit of variance around that — it obeys something called a bell curve. We base so much science on the bell curve. Bell-curve distributions arise when you deal with coins, or any collection where the pieces aren’t connected, like heights of people in a room. However, in most of the systems we’re interested in — the hard problems, be they of science or society — those distributions look very different than bell curves; they’re so-called fat-tail distributions.

Thinking about heights, instead of everybody being 5 feet 10 inches, on average, and maybe down to 4 feet and up to 7 feet, but certainly not 70 feet, with the distributions you get in these complex systems, you can get the 70-foot person. In fact, you can get the 700-foot person. There’s something about the way the pieces interact with each other that makes these extreme events happen: the 700-foot person, the stock market crash, the 9/11. So the interesting question is, is there a general science that can govern and tell us about these extreme behaviors? And if we can understand that for one system, can we transfer that understanding over to another one and therefore do something about it?

Source: https://www.quantamagazine.org/a-physicist-who-models-isis-and-the-alt-right-20170823/