The wait has been long, but the discipline of neuroscience has finally delivered a full-length treatment of the zombie phenomenon. In their book, Do Zombies Dream of Undead Sheep?, scientists Timothy Verstynen and Bradley Voytek cover just about everything you might want to know about the brains of the undead. And if you learn some serious neuroscience along the way, well, that’s fine with them too. Voytek answered questions from Mind Matters editor Gareth Cook.

How is it that you and your coauthor came to write a book about zombies? Clearly it is an urgent public health threat, but I would not have expected a book from neuroscientists on the topic.

Indeed! You think you're prepared for the zombie apocalypse and then — BAM! — it happens, and only then do you realize how poorly prepared you really were. Truly the global concern of our time. (Obviously the zombie apocalypse won't actually happen, but hey, if it gets people thinking about emergency preparedness, then that's a good thing. Good enough for the CDC, apparently.)

Anyway, this whole silly thing started when Tim and I would get together to watch zombie movies with our wives and friends. Turns out when you get some neuroscientists together to watch zombie movies, after a few beers they start to diagnose them and mentally dissect their brains. Back in the summer of 2010, zombie author and enthusiast — and head of the Zombie Research Society — Matt Mogk got in touch with me to see if we were interested in doing something at the intersection of zombies and neuroscience. Given that Tim and I had already chatted about this in the past, we decided to take him up on it.

Honestly this whole thing is a trick. A cheat. It's our underhanded way of getting people to learn something about real neuroscience, but we've dressed it up in gross, decaying, undead clothing. Neuroscience has a broad popular appeal, but it's easy to misrepresent and/or overhype relatively mundane findings. Neuroscience is also incredibly complex, which makes it hard to accurately communicate to the non-scientific lay public the reality of the field. So we use zombies as a hook.

Less scrupulous people use neuroscience to peddle their serious BS; we're using BS to peddle serious neuroscience.

I much prefer the latter.

What are some of the things you are able to explain, with the help of zombies?

We start with the obvious stuff: why do zombies move with such a slow, unsteady gait? Why can’t they talk? Do they feel pain? We use those obvious questions as stepping stones toward what we hope is a much more nuanced view of the modern neuroscientific understanding of how the three or so pounds of brain in your head can give rise to the complexities of the human experience.

Each chapter tackles a specific behavioral trait relevant to zombies, including movement, hunger, emotions, speech, and cognition. Quite frankly, we go into excruciating neuroscientific detail, but we pepper each chapter with (sometimes very strange!) anecdotes from the history of brain research.

We wrote the book with the intent that it could serve as an introductory neuroscience text.

Can you please explain the title, Do Zombies Dream of Undead Sheep?

It's an homage to Philip K. Dick's beautiful book, Do Androids Dream of Electric Sheep, which was later adapted by Ridley Scott into the movie Bladerunner, with a phenomenal performance by Harrison Ford as Rick Deckard.

The story is complex, but in part it is about what it means to be human. Hence the book's title, which is an allusion to the question of consciousness in artificial intelligence. In our book we touch a bit on the question of whether zombies are conscious — whether they have that spark of self-awareness we associate with being human. This is a deep question — perhaps the question — in the philosophy of mind.

It's also a play, because in the philosophy of mind, there is a thought experiment that asks the reader to imagine a person, exactly like you or I or any other person in every conceivable way, except for the fact that they lack self-awareness/consciousness/sentience. This imaginary being is referred to as a "philosophical zombie", or a "p-zombie."

What is the strongest case for zombie consciousness? And the case against?

The strongest case for comes from the recent movie “Warm Bodies” wherein some of the less desiccated zombies, such as the protagonist R, have a rich internal dialogue, self-awareness, and emotions (though they can’t always exert control over their behaviors). Similarly, the alternative universe run of the Marvel Zombies comics also shows the zombie superheroes and villains as being capable of complex thoughts and behaviors indicative of consciousness. But these are pretty rare examples, as the vast majority of zombie movies show them as mindless killers.

So I guess the strongest case against zombie consciousness would pretty much be the entirety of the zombie genre. Granted, it’s quite difficult to define consciousness, but much like US Supreme Court Justice Potter Stewart’s views on pornography, most of us, “know it when we see it,” and zombies ain’t it.

Can you tell me what you learned about Haitian zombies?

I learned that belief can be a very powerful thing. Well, belief combined with very powerful neurotoxins and hallucinogens, anyway.

We go into detail in our book about the cultural roots of the Haitian zombie. The word “zombie” comes from an African root word “nzambi”, meaning “spirit of a dead person.” Within Vodou, a priest (bokor) can sometimes be asked to take possession of the soul of a particularly troubled or threatening individual. The bokor induces “death” and separates the “little good angel” spirit (the ti bon ange) from the body. Once “resurrected,” the physical body of the person is then forced to work at the will of the bokor.

An anthropological investigation by the ethnobotanist Wade Davis postulated that the process of making a Haitian zombi is neuropharacological, wherein bokor use a chemical found in many animals (especially puffer fish), called tetrodotoxin (TTX), to paralyze their targets and induce a near death-like state in them. A sublethal dose of TTX allows the person to “die” and be “resurrected”. During the recovery, the victim is forced to consume datura, a plant that contains chemicals such as scopolamine and hyoscyamine, powerful hallucinogens that leave the person delirious and compliant. Datura leaves the victim in an altered state of mind that makes them easily coercible.

The whole idea is fascinating. It sounds so far-fetched and unbelievable, but from a neuroscientific and psychological perspective, it’s not impossible.