Survival Unlikely When Emotions are Factored into Zombie Apocalypse
October 18, 2012 § Leave a comment
If there’s one thing that’s probably not going to happen this Halloween, it’s a zombie outbreak.
Okay, background: as we all know, the fictitious disease that is zombieness is a highly complex one. It has a very short incubation period, results in widespread chaos, and is transmitted by a population so wholly unconcerned with our well-being that not only will they not wash their hands after blowing their noses, but they’ll actively try to bite healthy people—which results, by the way, in guaranteed infection. According to most movies I have seen, there is also no cure and no spontaneous recovery.
Zombies are also very fashionable lately, both in popular entertainment and in science. Several papers have already mapped out the theoretical spread of a zombie outbreak. The CDC once cheerfully attempted to use it as a preparedness example—and later, when several incidents of face-eating broke out, issued a warning that no, really, zombie attacks were definitely not happening.
But there was something about all this, particularly about the models, that gave the authors of this new study pause: the simulations didn’t account for human emotions. Where was the panic? The herd-like stampede into what inevitably proves to be an untimely death? How can we possibly take such cold-hearted zombie simulations seriously?
According to popular mythologies, a zombie outbreak should impose a situation where people behave very unconventionally, being guided mostly by their panic, heavily focused towards personal survival, obeying population patterns beyond themselves. In such an event, people’s situational awareness should be a key element to modulate the internal population dynamics.
In their model, which they present in this paper, there are three different levels of panic (p1, p2, p3; cold-stone zombie killing experts, which I picture as Kurt Russel in Soldier—not a zombie movie, but a very good movie—can also experience zero panic, or p0). Panic levels in a given person can fluctuate according to all sorts of different inputs: state of having been bitten or not, spread of zombies to your city, and the level of the surrounding people. (Are they zombies? Panic! Are they other panicked people? Panic more! Are they Kurt Russell and Ripley with machine guns and a battle axe? Congrats and calm down!)
Other variables include zombies (Z), people on their way to becoming zombies (I), really dead people (R), treatment (T), and those killing experts (E) I mentioned already. If that sounds like a lot, a) that’s not all, I’m actually sparing you a lot of detail here, and b) we’ve already established that zombie outbreaks are inherently very tricky.
Kicking things off with a theoretical outbreak in a city more or less similar to Santiago de Chile and its surrounding cities, the researchers plugged all this into the computer simulator and watched what happened.
In 974 cases out of 1000, everybody loses and we all turn into zombies. Infection spreads quickly outward from the starting city within days. The introduction of treatment has success that is, at best, touch and go, particularly given the short window an infected has to take it before becoming a full zombie. In a best case scenarios in which we do survive, treatment availability hits 30 percent, and a full eight percent of the population are expert zombie killers, although other variants of those proportions also led to success, in the 26 instances in which we didn’t all succumb.
Panic skyrocketed within half a day of the start, bringing with it the inevitable chaos. Transportation options plummeted in tandem with panic’s rise. Traffic jams, I assume; we all read The Stand, right? Also included in the original parameters is the reasonable concept that high panic levels also tended to mean increased risk in general for an individual, on account of the resulting running around and freaking out.
Now, there is a real world tie here. It’s a little tenuous, but the authors do make the excellent point here that any and all disease spread models need to account for panic. A major change in emotional state like that will almost certainly affect the spread of even actual pandemics:
To date, many models studying the spread of infectious diseases assume that the population will not change its behavior in response to a disease outbreak [24,25]. However, understanding the influence of populations’ behavior on the spread of infectious diseases is key to plan, apply and improve any control measure … As expected from our implementation, the global dynamics of the infection progression on the population resulted primarily governed by the mechanistic description of local interactions. Notoriously, people’s situational awareness resulted essential to modulate the inner dynamics of the system. These findings support the notion that, at least for pandemics with similar characteristics to this zombie outbreak, information moves faster than contagion. As demonstrated by pandemic episodes like SARS and, more recently, H1N1 (avian flu), governments and authorities should make extensive efforts to improve the situational awareness of the population being affected.
But this is softened somewhat by the big honkin’ caveat that this is a paper about zombies, which means:
It is important to note that these viruses are not meant to represent the progression of actual viruses in a host organism.
The moral of the story? Don’t Panic.