Tragedy of the Blood Commons: The Case for Privatizing the Humans

Excerpt from Chapter 15, by Glen Whitman

The film Daybreakers offers a cautionary tale for vampires: a dark future in which vampires have hunted humans to the brink of extinction. Despite getting many details of our physiology and culture wrong, the movie depicts a starvation scenario that is no idle fantasy. At present, humans are plentiful and vampires relatively rare—but that pleasant situation may not last forever. The rising vampire population, together with declining human birthrates in developed countries, could eventually turn human blood into a scarce resource. We need to think seriously about how to manage our food supply before it’s too late.

Our dilemma is hardly unique. Humans, too, have faced situations in which valuable economic resources have been devastated by excessive consumption—for instance, fish in the international oceans, elephants in Africa, and buffalo on the nineteenth-century American plains. In most of these cases, the culprit was not simple greed or gluttony; if that were true, then wheat and cattle would also have been harvested and slaughtered into extinction. Instead, the problem arises from poor incentives to manage resources that are openly available to everyone.

Human economists have given this problem a simple name: the tragedy of the commons. And economic theory and practice have shown that, under the right circumstances, it has a simple solution: private property rights.

Put simply, vampires may someday need to privatize the humans.

To understand the perverse incentives that accompany open-access resources (also known as common-pool resources or “commons” for short), it’s useful to consider a short parable.

The vampire Reynaldo has trapped a young human woman in a dark alleyway. Just as Reynaldo is preparing to sink his fangs into her flesh and suck her dry, his keen hearing picks up something unusual… a second heartbeat. The woman is pregnant!

Reynaldo pauses for a moment, deciding what to do. Maybe he should let her go. If he does, then the woman will eventually give birth. At some later date, Reynaldo thinks to himself, he can trap her again, drain her, and still have her offspring left for dessert. And being immortal, Reynaldo isn’t so impatient that he couldn’t wait a while longer. Resisting his bloodlust for now seems like the rational thing to do.

And yet . . . if Reynaldo lets this woman escape, who’s to say it will be Reynaldo who gets to drink her later? There are plenty of other vampires out there, all of whom would happily take this woman’s lifeblood, and her child’s, too. If there are just nine other vampires out there, Reynaldo thinks to himself, then he has only a one in ten chance of being the lucky one. So it’s one meal for sure now, versus a 10 percent chance of two meals later. Reynaldo frowns as he does the math. . . .

And plunges his teeth deep into the young woman’s neck.

Reynaldo’s choice is not unusual; humans face similar choices on a regular basis. Take ivory hunters in Africa. Despite an international ban on the ivory trade, hunting elephants for tusks to sell on the black market remains a lucrative business. Think about the incentives of an ivory hunter with a vulnerable baby elephant in the crosshairs of his gun. He can kill the elephant now, claiming its tiny tusks as his reward. Or he can let it escape, in which case it will grow up, grow much larger tusks, and possibly give birth to more baby elephants. But if he lets it go, the odds are very low that he personally will reap the gains; after all, there are lots of other hunters out there. And so, like Reynaldo, our hunter faces a choice: a sure prize now or a small share of a larger prize later. The rational response? Bang!

It might seem like the problem arises from the hunter’s lack of certainty: the present gains are guaranteed, while the future gains are risky. But the real problem isn’t the risk; it’s the sharing. Even if Reynaldo were guaranteed a 10 percent share of the young woman and her child’s blood, he would still prefer to have 100 percent of a victim now. Likewise for the ivory hunter. The gain from allowing the human or elephant population to grow is not enough to overcome the loss from having to share.


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