Everything You Ever Wanted to Know About Zombies

by Mogk, Matt

  Our work provides clues into how animals must construct a complete, fully navigable representation of their environment in order to move around, even if they’ve only partially explored that environment.16

  Memory and learning are so tied to our ability to make simple choices that without them, a zombie would likely not be able to tell the difference between a door and a wall, let alone find its way out of a dead-end alley. A front door covered in paper or tape could be enough to confuse this type of zombie, rendering the door virtually invisible.

  But to understand the potential differences between learning in the living and in the undead, we look to findings from the California Institute of Technology that show that humans use a complex combination of two learning processes to navigate through their world: (1) model-free learning and (2) model-based learning.

  Model-free learning is based on trial-and-error comparisons between the anticipated reward and the reward we actually receive in any given situation. For example, a zombie bangs its head against a brick wall and doesn’t gain access to the screaming children inside the house. It then bangs its head against a window, the window breaks, and the zombie gets rewarded with a nice meal. Moving forward it will now be more interested in windows than walls.

  By contrast, model-based learning is a more complex system whereby the brain builds a virtual map of the environment to understand different situations. A model-based thinker doesn’t need to stick with what he knows from past experience and so is able to make sudden strategic shifts.

  If zombies are indeed unable to accomplish complex tasks such as unlocking doors or using weapons, it may be because they rely too heavily on a largely model-free view of the world that is not adequately balanced by the higher-functioning model-based system. In this case, they could learn little lessons along the way, such as that walls aren’t good for eating children but windows are. They would not, however, achieve great leaps in knowledge and eventually overpower humans with their smarts alone.

  According to Romero, zombies develop the ability to work together in teams. They communicate with one another. They can learn to enjoy music, follow directions, use weapons, and eventually even outsmart humans. Romero zombies also retain memory of their past lives and personalities and act out past rituals and habits. Their learning ability seems to far outpace common beliefs about the modern zombie.

  Zombies apparently must possess some level of memory and learning to navigate through our world, and the limit to their developmental abilities may be related to their sleeping habits. A study from Harvard University strongly suggests that sleep enhances memory and learning in humans. If, as many believe, the undead never actually rest in their constant search for fresh meat, a zombie’s inability to develop new skills may have much more to do with its insomnia than with its actual potential to learn.

  The Harvard study’s coauthor Robert Stickgold explains that task-related dreams are triggered by the sleeping brain’s desire to consolidate challenging new information and to figure out how to use it. Making even the most basic choices requires constant low-level learning, but if zombies don’t sleep at all, then their ability to collect data and cognitively advance may be shot.

  By endlessly hunting humans, the undead may be robbing themselves of the chance to become even deadlier hunters. So if you ever see a zombie nodding off for a quick nap, you might want to think about waking it up.

  A sleeping zombie could be a learning zombie, and nobody wants that.

  Land of the Dead (2005)

  RILEY:

  They’re moving toward the city.

  KAUFMAN:

  They’ll never get across the river.

  RILEY:

  I wouldn’t be so sure. They’re learning how to work together.

  KAUFMAN:

  They’re mindless walking corpses, and many of us will be too if you don’t stay focused on the task at hand. Zombies, man. They creep me out.

  KNOW YOUR ZOMBIES: BUB

  Day of the Dead (1985)

  Romero’s third zombie film depicts the undead as capable of learning new skills and evolving over time. Bub still craves human flesh, but he’s not such a bad guy overall. He enjoys music, has a basic understanding of tools, salutes his superior officers, and even learns how to shoot a pistol.

  While Bub becomes more refined, the humans in Day of the Dead devolve into a chaotic, bickering gang of thugs. Romero begs the question: who is the real menace?

  ILLUSTRATION BY JOSH TAYLOR

  8: ZOMBIE BLOOD

  Human blood is charged with delivering needed nutrients and oxygen to waiting cells in the body and removing waste from those same cells. It contains a substance called hemoglobin, which gives blood its color and contains enough iron to make red cells subject to the effects of magnetic fields.

  Many cultures have used magnetic therapy to treat illness and encourage blood flow to specific parts of the body for centuries. A 2003 University of Virginia study showed that human blood can be propelled through the vascular system by magnets.

  Because it’s clear that the undead possess a fundamentally different physiology from that of your typical human corpse, as evidenced by their walking around and eating people, it may be that changes occurring in the electrical pulses of the brain as it passes from human to zombie create the necessary conditions for magnetization.

  STAGNATION OR CIRCULATION?

  Though it is widely believed that all blood flow in a person infected with the zombie sickness ceases at death, a compelling counterargument might be that the undead brain has a constant hunger for blood in order to continue working properly. A brain without blood flow would very quickly dry out, crack, and become little more than a lump of brittle nothing. University of California, Berkeley, neuroscience professor Marian Diamond points out that without blood irrigation to the brain, all channels would flatten, and there would be no brain function and no sitting up or walking around. So it makes sense that there is a mechanism for zombie blood flow.

  In a living human, 20 percent of the blood pumped from the heart goes into the brain. To put this in perspective, an adult male dedicates up to 500 percent more blood to his brain than should be required by weight distribution. Even if zombies function at a substantially reduced capacity compared with their human counterparts, the amount of blood used on a constant basis is staggering. So it stands to reason that if there is blood moving in the brain, then there should be blood moving through other parts of the body.

  And if blood does move through zombie bodies without the aid of a beating heart, we must then discover what is likely driving the system and exactly how it works. As is often the case in zombie research, a single hypothesis leads to many more questions.

  Because the pathogen moves freely throughout the host, is it possible that the pathogen itself has evolved an independent oxygen-carrying capability?

  —The Zombie Autopsies (2011), Steven Schlozman

  One thing is certain: it’s impossible for the undead to present a credible threat to the living if their blood reacts in a similar manner to that of deceased humans, because they would simply not be able to move around well enough to hunt. The gravitational pooling of blood in a corpse, called livor mortis, causes blood to flow toward the part of the body closest to the ground. As the blood accumulates, that area swells and becomes discolored, stretching the flesh to the point of breakage.

  In the case of a zombie that stands up and seeks out prey, livor mortis could mean that all blood inside the body quickly moves to the feet, bursting through the skin and destroying any remaining tissue. The undead menace would be literally walking on bones alone. And those bones, absent the protective casing of flesh and muscle, would also break apart in short order.

  So unless you believe that zombies are short creatures that awkwardly hobble around on leg-bone stumps, more prone to falling over than to eating people, it seems clear that something is happening to undead blood to make it behave differently from how it normally would in a corpse. />
  SPREADING THE INFECTION

  The zombie sickness is generally believed to be spread through the transfer of blood, saliva, or other bodily fluids. You get bitten or sprayed in the mouth and eyes with toxic zombie goo, and soon enough, you’re weak, confused, and fast on the road to becoming an undead ghoul yourself. Because of this, Todd Thorne, president of the International Association of Blood Pattern Analysts, argues that zombie blood must circulate, even without being forcibly pumped by a beating heart, or else it wouldn’t be able to transmit from one body to another. In fact, without circulation, there would be no blood at all.

  Blood-borne illnesses travel through the human body by catching a free ride on our fast-moving highway of arteries and veins, but after death, the highway grinds to a sudden halt. If zombie blood doesn’t flow on its own, then the infection would stop advancing at the moment a person dies. In the case of a quick death, the tainted blood wouldn’t have time to reach the brain or central nervous system, and that newly dead person would therefore not become a zombie.

  Following this logic, if zombified blood is not able to flow at will, then a person who is bitten on the hand and soon after fatally shot through the chest would likely not become a zombie even though the brain was never destroyed. As long as death occurs before the zombie infection has fully taken hold, then another member of the undead legion would not be created.

  In Romero’s world, everyone who dies for any reason turns into a zombie. The zombie bite only serves to speed up a person’s death but doesn’t change the inevitable fate of every man, woman, and child on the planet to turn into a flesh-starved zombie once expired. The cause of death is not important, as it is the death itself that creates the new zombie.

  Adding more weight to the argument that zombie blood likely flows, in 2010, researchers at Vanderbilt University showed that when cells move about in humans, they mimic the behavior of amoebae and bacteria searching for food. Study participant Alka Potdar explains that for the first time, we have a general framework for fully understanding the way cells move. And since the framework for self-propelled motion already exists inside human beings, a zombie sickness has only to insert its own selfish intention into the body’s existing structure to create an army of walking dead that enjoy the benefits of some level of blood flow.

  Star Trek: Infestation #1 (2011)

  MCCOY:

  Whatever was transmitted from Padilla’s bite is coursing through your system with unprecedented speed and aggression.

  BARNES:

  You mean it’s going to happen to me too? You’ve got to do something!

  KIRK:

  Bones, isn’t there anything . . .

  MCCOY:

  Damn it, Jim. I don’t even know what we’re dealing with yet!

  And if zombie blood does in fact flow through the body in some manner, this may have an impact on the commonly held belief that the undead freeze in cold weather. A zombie with flowing blood probably functions much more like a cold-blooded animal than the warm-blooded human it used to be.

  Several species of cold-blooded fish have a special substance in their blood called glycoprotein, which acts like antifreeze to help them survive very cold water temperatures. Glycoprotein depresses the freezing temperature of blood sufficiently to render the body immune to the cold. Much like a bottle of vodka in a freezer box, while everything around it is frozen stiff, it never changes from its liquid state.

  If the undead body is able to access the existing glycoprotein therein, it may then have a workable system that no longer needs to regulate internal temperature in order to function. Though zombies would still likely move more slowly in extreme cold, their blood would never convert into a solid, continuing to flow and power the body.

  9: ZOMBIE HUNTING TECHNIQUE

  Though he never made a zombie movie, Alfred Hitchcock is one of the pioneering masters of modern horror in film. Reflecting on what causes people to feel the chill of fear right down to their very bones, Hitchcock observed that there is no terror in the bang, only in the anticipation of it. And isn’t that the true essence of the zombie?

  In their pure relentlessness, zombies are consummate hunters. They are the embodiment of a constant awareness of the inevitability of death. They never stop. They never plot or scheme. They can’t be bargained with or shown sense in reason. They have no meaning, no choice, not even any recognition of the existence of choice. They’re simply forever shambling your way, hunting you, trying to get just close enough to claw, to grasp, to chew.

  They have no regard for the survival of any species, including their own. As long as they’re able, zombies will hunt until every last available prey is either destroyed or turned into yet another undead ghoul. Sustainable living isn’t in a flesh eater’s vocabulary, and this spells big trouble for the human race. But could their insatiable appetite actually be the magic bullet that saves the planet?

  Mass extinction of species throughout history has served as Mother Nature’s reset button, periodically allowing the earth to refresh and renew itself. However, many scientists argue that humans are unnaturally speeding up this process through overpopulation, resource depletion, and climate change, ultimately leading to irreparable damage. Cue the zombies.

  In the event of a global zombie plague, there would be no need for a new ice age to destroy the billions of different animals and plants already living in harmony. Mankind, as the infecting parasite that has upset this delicate balance, would simply eat itself out of the equation. As the remaining hordes eventually sank back into the earth, the rest of the world’s species would then be able to go on living as if we were never here in the first place.

  It’s great fun to crash a bus through a department store window as the driver finds himself torn to shreds by the suddenly zombified passengers. But in the end the world, appearance-wise, survives.

  —Zombie Spaceship Wasteland (2011), Patton Oswalt

  Of course, the fact that your demise may contribute to the global good will likely provide little comfort when a pack of hungry zombies breaks through your hasty home defenses to chew your arms off. If any of us hopes to survive long enough to see us destroy the planet ourselves, a more complete understanding of how the undead may hunt the living is needed.

  HOW DO THEY FIND US?

  Prevailing wisdom suggests that zombies do not simply stumble about without purpose but, instead, do everything in their power to relentlessly hunt and kill the living. To that end, their seemingly random pattern of movement when not actively stalking prey may more closely mirror that of many predators when locating food over great distances.

  Hungry sharks, turtles, fish, and other marine predators use a hunting system known as the Levy walk or Levy flight.17 Though it appears to be random wandering, the Levy walk is actually a superior strategy for finding prey in vast areas where food is sparse and hidden.

  David Sims of Britain’s Marine Biological Association developed a computer model confirming that the predatory patterns are optimal for naturally dynamic prey fields, because the Levy walk involves moving in short bursts in many different directions, before taking a long advance toward a single point and then repeating the process. This allows a hunter to investigate one location before jumping to a completely different spot.

  A 2010 study done by researchers at North Carolina State University found that humans also follow the Levy-walk patterns commonly observed in animals such as monkeys and birds:

  Our study is based on about one thousand hours of GPS traces involving 44 volunteers in various outdoor settings including two different college campuses, a metropolitan area, a theme park and a state fair.18

  If zombies instinctually employ the Levy walk the way sharks and humans do, their travels around a mostly abandoned city would allow them the best chance of finding and eating the few remaining humans left. In rural areas, a remote farmhouse could be stumbled upon in the least amount of time and with less effort, meaning that the apparently chaotic movement of the undead ma
y in fact be leading them straight to your front door.

  Hell of the Living Dead (1981)

  MAN:

  I can’t see how many of them there are.

  WOMAN:

  Just look at their faces. They look like monsters.

  MAN:

  They could be drunk, or drugged. Or maybe it’s a leper colony. They probably don’t intend us any harm.

  WOMAN:

  I don’t know. I wouldn’t be too sure.

  ZOMBIE TOUCH

  Once a zombie is within striking distance of its potential meal, how is it able to differentiate its living prey from others of its own kind? If zombies hunt by sight, then walking like a zombie could afford potential victims functional invisibility. If they hunt by smell, then certain antiodor measures could be employed. Looking at the hunting technique of the smallest predatory mammal on the planet, the Etruscan shrew, one interesting hypothesis suggests that zombies use their sense of touch to find, capture, and devour their victims.

  The tiny shrew must eat twice its body weight every day to keep from starving, and the animals it hunts—crickets, cockroaches, and spiders—are often as big as the shrew itself. It spots potential prey visually, then moves in to feel and confirm. Much like a zombie reaching out for its next meal, the shrew decides what to attack by touching targets with its nose and whiskers.

  Because it’s widely believed that zombies are cold-blooded and because their imperfect body is dead and rotting, it stands to reason that the undead would have no trouble identifying a warm, soft, living person using this touch method. Interestingly, this may also explain why zombies are thought to move about in packs. If they gather to investigate one another through touch, they would then be in a naturally formed group as they moved on to seek out humans to eat.