Everything You Ever Wanted to Know About Zombies (8 page)

Echoing their work, McGill University researchers offer a clear breakdown of the human brain’s control over motor function, explaining that even basic movements—walking, looking around, grabbing—require complementary actions taken by the brain as a whole. It’s akin to a ship’s crew, whereby the frontal lobe receives information about the individual’s current position from several other parts, then, like the ship’s captain, issues commands. The major difference between humans and zombies is that commands such as
Walk to your car to go to work
or
Open the microwave to heat up a Hot Pocket
are changed to
Eat Mr. Johnson mowing his lawn
and
Eat the paramedic helping Mr. Johnson.

A 2010 study at Carnegie Mellon University showed that humans and other animals use real and hypothetical memory to help make basic decisions. When applied to zombie research, this fact suggests that the undead probably have some developmental ability in order to hunt their human prey effectively. In layman’s terms, zombies might learn.

The study found that rats navigating a maze used not only replays of recent or frequent paths through the maze but also paths that they’d rarely taken or had not yet taken at all. The rats were trying to build mental maps to help them make navigation choices, proving that memory is an integral part of the decision-making process. Researcher Anoopum Gupta
notes that this is true even if the goal is something as simple as sniffing out a piece of cheese:

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.
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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.

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.

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

H
uman 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.

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.

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.

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.