(Male announcer) Thank you for downloading from the BBC.
For details of our complete range of podcasts and our Terms of Use,
go to bbcworldservice.com/podcasts .
(Female announcer) Governments worldwide battle to control and contain terrorism.
Police and the courts struggle to separate harmless loners from dangerous lone wolves.
Opinions differ on the most effective way to combat terrorist attacks,
from military interventions on the ground, to curbing political and religious radicalisation.
But in this edition of Discovery, we'll be hearing about a more unusual new weapon
that might be used in the future to fight terrorism:
maths (1:00)
(A) We were looking at the data in a new way, we were using tools that were somewhat foreign,
(A) these were tools that came out of physics and complex systems, not tools that necessarily came out of the political science community.
(A) And we were saying things that were kind of weird.
(B) One thinks of terrorism as something very random, something so strange that it must be done in a very chaotic way.
(B) But of course, in the end, it is an activity, it's a human activity, so it's quite interesting then that the patterns that you seen in the events are not random.
(A) For terrorism, that had somewhat shocking implications.
(A)If you understand the frequencies of the small events, you can extrapolate,
(A) and then make a forecast out into the future, about what the probability should be
(A) for a very large event.
(HF) So, could maths predict the next 9/11?
(HF) You're listening to the BBC World Service, and today on Discovery, I'll be looking at the hidden mathematical pattern that is being discovered in global terrorism;
(HF) a pattern that lies behind a host of diverse phenomena, from economics to earthquakes.
(HF) I'm Dr Hannah Fry, and I'm a mathematician from University College London, working on complex systems.
(HF) These are systems, like terrorism, which at first seem complex, and random
(HF) but if you stand back and study the bigger picture, then a surprising number of patterns can appear;
(HF) patterns which you can describe using mathematics.
(HF) Dr (?), a computer scientist at the University of Colorado, was one of the first to find a tangible, mathematical connection underlying terrorism.
(HF) He looked at 30,000 terror attacks worldwide, over 40 years
(HF) and for all of the events, he counted how many times a certain number of people were killed, and plotted it on a graph
(HF) and the results were remarkable.
(Dr) This initial analysis we did, it was quite shocking, we found this thing that looked like
(Dr) what's called a power law distribution, which is a very special kind of mathematical pattern that usually
(Dr) crops up in physics, in fact, but increasingly is observed in social and biological systems,
(Dr) and this is somewhat surprising, because when we think about terrorism,
(Dr) we think mainly about the capricious, highly contextualised nature of the individual actors
(Dr) that carry out these events,
(Dr) and yet, at the global level, we see this remarkable pattern, this power law pattern, emerge.
(HF) So it's obviously a bit tricky to describe a graph on the radio. (Dr) [Laughs] Yes.
(HF) but could you give us an idea of what a power law looks like,
(HF) perhaps, compared to some other distributions that people might be familiar with?
(Dr) So a power law distribution is very different from
(Dr) what most of us experience, and our intuition is built around, as human beings.
(Dr) Most of our world is wrapped up in what are called Gaussian, or normal, distributions.
(Dr) So, the range of heights that we experience among other humans,
(Dr) has what's called a normal distribution. (HF) Like a bell curve.
(Dr) [Confirming] Like a bell curve. Which means that there's an average,
(Dr) that is representative of essentially the entire population.
(NJ) One of the first graphs that we ever draw in school is one of heights of people in the classroom
(HF) Neil Johnson, professor of Physics at the University of Miami. (4:14)