Who Will Win In Human, Zombie War?
MELISSA BLOCK, host:
From NPR News, this is ALL THINGS CONSIDERED. I'm Melissa Block.
ROBERT SIEGEL, host:
And I'm Robert Siegel.
We learned recently of a book on mathematical models of infectious diseases that is frankly way over our heads, but includes a very unusual and conceptually accessible paper by a team of mathematicians in Ottawa. It's about a different kind of contagion. Think "Night of the Living Dead."
(Soundbite of movie, "Night of the Living Dead")
Unidentified Man: The dead whose haunted souls haunt the living.
SIEGEL: Zombies. The article is called "When Zombies Attack: Mathematical Modeling of an Outbreak of Zombie Infection." And while I can't handle the equations that the authors derive, here's what they write in their abstract: We introduce a basic model for zombie infection, and we show that only quick, aggressive attacks can stave off the doomsday scenario, the collapse of society as zombies overtake us all.
Well, joining us to talk about all this is Professor Robert J. Smith?, who does applied mathematics in the math department and on the faculty of medicine at the University of Ottawa.
Welcome to the program.
Professor ROBERT J. SMITH? (Applied Mathematics, University of Ottawa): Thank you.
SIEGEL: And I say Professor Smith? that way because your name is spelled with a question mark. You've written that you're asked about that about 15 times a day. So before we get to the zombies, let me keep your average up here. Why a question mark?
Prof. SMITH?: A couple of reasons. One is there are, I think, about 20 pages of Smiths in the phone book. There are Robert Smiths all over the place, in my class and everything. So I decided to add some punctuation to liven it up a little.
(Soundbite of laughter)
SIEGEL: And that is your name, that's how it's spelled?
Prof. SMITH?: That is my name, yes.
SIEGEL: You've worked, I've read, on mathematical models of the spread of HIV, of malaria. What led you to zombies?
Prof. SMITH?: It was actually a class project. I was teaching a course in disease modeling. And I said to the students, you can do anything you like as long as it's disease. And one group came up and said, well, we have an idea, but it's a little bit out of the box. And I said, sure. You know, what have you got? And they said, zombies. And I think they thought I'd shoot it down, but actually I said, go for it. That sounds really great.
And it was just a fun way of really illustrating some of the process that you might have in modeling an infectious disease.
SIEGEL: We're talking about zombies. Literally out of the box they've emerged.
Prof. SMITH?: Yes.
SIEGE: Tell us about the characteristics of zombies in your model.
Prof. SMITH?: Right. So if you're modeling an infectious disease, you might have people who are susceptible to a disease, those who are infected and those who are removed. And the removed is often, usually the recovered people who might have some immunity.
And so what we modeled with zombies, we said, well, we've got susceptible humans. Then you've got the people who are infected with the zombie virus, so they are zombies. And then you've got the removed class, but the removed class, instead of being recovered, are the dead. And the reason we had to model the dead was because the dead can come back to life.
Prof. SMITH?: And this is very, very different from most diseases, obviously.
(Soundbite of laughter)
SIEGEL: Yes, it is, yeah.
Prof. SMITH?: Yeah. Which, in fact, for me, this is the exciting part because it's - you're modeling zombies. The challenge was you're dealing with an unfamiliar outbreak. You can't use an existing model because you have to, you know, have the dead come back to life.
So what we had to do is create it from the ground up. So you have to understand the so-called biology of the disease, then you have to create your equations. And then what you do is you start to refine your equations, and you say, well, okay, I've got some idea, but now I look - and I say, well, there's a bit more realism that I'd want to put in, or there's a few other effects I might want to conclude.
SIEGEL: So, how do we survive an attack of the zombies?
Prof. SMITH?: Well, at the end of each movie, what you see is you is - you see the army moves in, and they start just destroying the zombies. So they cut off the heads, they shoot the brains, and they basically take out the zombies in a series of attacks.
So that's what we decided to model as the end point, was the army comes in from nowhere and just bang, bang, bang, you kill all the zombies.
(Soundbite of laughter)
SIEGEL: That's how we'll survive the zombie attack.
Prof. SMITH?: Yes. Yes. Exactly.
SIEGEL: Professor Smith?, thank you very much.
Prof. SMITH?: You're very, very welcome.
SIEGEL: That's Professor Robert J. Smith? of the University of Ottawa.