They concluded that the best course of action to protect the integrity of their (and your) cerebral cortex in the event of zombie incursion was to head for the hills or, more precisely, the Rockies, to stand any chance of survival.
World War Z, an oral history of the first zombie war, first published by American horror author and screenwriter, Max Brooks, in 2006, was the inspiration for a group of Cornell University researchers to examine how an “actual” zombie outbreak might play out in the U.S. World War Z has since been released as a movie starring Brad Pitt.
But the Cornell researchers’ work had a serious side. From modelling the statistical mechanics of zombies, they hoped to bring that “undead” data to life in revealing more about how diseases spread in the here-and-now. The group will describe their work at an upcoming meeting of the American Physical Society, scheduled for San Antonio, TX March 5.
So why model the mechanics of zombies? As Alex Alemi, a graduate student at Cornell University, explained, “Modeling zombies takes you through a lot of the techniques used to model real diseases, albeit in a fun context.”
The research team’s project comprised an overview of modern epidemiology modelling. It kicked off with math using differential equations to model a fully connected population. It then moved on to lattice-based models — complex interactions between individuals, groups of individuals and organizations — to gain a further insight into disease spread. Finally it scaled up to a full US-wide simulation of an outbreak across the continental US.
The whole exercise involved a good deal of computational results generated from different simulations. The researchers likened it to chemistry. They described the simulations as akin to modeling chemical reactions taking place between different elements except that in the case of zombification affecting a population of 300 million or so across the US, individuals could exist in one of four states: human, infected, zombie, or dead zombie.
From that it’s easy to perceive that the project’s large-scale simulations have an element of randomness, or, to give it its technical term, are stochastic in nature.
As Alemi explained, “Each possible interaction–zombie bites human, human kills zombie, zombie moves, etc.–is treated like a radioactive decay, with a half-life that depends on some parameters, and we tried to simulate the times it would take for all of these different interactions to fire, where complications arise because when one thing happens it can affect the rates at which all of the other things happen.”
The study found a real-life zombie apocalypse would play out quite differently from such scenarios as they’re often portrayed in movies and in sci-fi or horror.
As Alemi explained, in most zombie fiction, be it films or books, “if there’s a zombie outbreak, it’s usually assumed to affect all areas at the same time, and some months after the outbreak you’re left with small pockets of survivors. But in our attempt to model zombies somewhat realistically, it doesn’t seem like this is how it would actually go down.”
Cities would quickly fall prey to the zombies but, according to the simulations, it would take weeks before zombies held sway in less densely populated areas. And in the best Hollywood traditions of “head for the hills,” the safest refuge would be the northern mountain-time zone. There, it could be many months before zombies constituted a threat to public health.
Less humans to bite
The dynamics of the disease dictate that once the zombies invade more sparsely populated areas, any zombie apocalypse moves to slow-mo — or slow lingering denouement, if we’re still in Hollywood mode. For, out in the countryside, there simply aren’t enough humans to bite in order to sustain the speed at which cities became ground zombie.
Somewhere among the Cornell research, Alemi thought there might be a half-decent movie plot, commenting, “I’d love to see a fictional account where most of New York City falls in a day, but upstate New York has a month or so to prepare.”
So there you have it. If you’ve ever lain awake at night fretting what to do if zombies are in the neighborhood then the solution’s simple: head for the northern Rockies.
Of course that practical recommendation has its limitations, particularly if some inconsiderate zombies should go on the rampage outwith the continental United States.
In that event, never, ever, be afraid. Just reach for the remote.
