on vampires, exponential population growth, and scientific literacy

Eleven years I wrote a tongue-in-cheek blog post about vampires and stochastic processes. I was inspired by my course material about Markov chains and branching processes, which has application to the spread of infectious disease, to the vampire population dynamics in the Twilight series and other teenage vampire stories that were very popular at the time.

I have a great deal of skepticism about vampires.

Here’s my problem with vampires. I have a hard time believing that there would be just a few vampires out there and that the existence of vampires would be such a well-kept secret. After all, they reproduce rather easily (a single vampire could create thousands of offspring, whereas there are limits to human reproduction) and vampires don’t die easily. If there were vampires, they would almost certainly outnumber humans (but then vampires would run out of food).

This argument becomes even more overwhelming if you model a vampire population as a branching process or birth-death process and assume that each vampire in the population has probability Pj of producing j offspring (with j=0,1,2,… ). The vampire population would either explode or die out, depending on the expected number of offspring per vampire. But if you take into account the fact that vampires live many, many generations (they’re virtually immortal) and may create thousands of offspring, the population explodes (if you assume that each vampire creates at least one vampire, on average, before it dies). With those numbers, vampires would not be living under the radar–they would be everywhere!

I have yet to see a vampire movie that implicitly assumes that there is a reasonable model for vampire population dynamics (using a stochastic process framework or something else). And frankly, I’m pretty disappointed. Until I am offered a reasonable explanation for why there aren’t more vampires, I won’t be able to jump on the vampire bandwagon.

This issue had been bothering me since I first saw The Lost Boys, long before I knew about Markov chains. I enjoyed The Lost Boys, but I did not enjoy it’s inability to acknowledge exponential vampire population growth. Markov chains later helped me understand why my skepticism was valid.

The post went viral. Life was interesting for awhile. Twilight fans hated me.

My blog post was never intended to be taken seriously. It was not a serious critique of vampires, because vampires aren’t real.

Once in awhile, I google myself to see what turns up. Over the years, I have found that several vampire fan news sites and blogs that existed at the time (teenage vampire stories were very popular at the time) picked up my blog post and wrote serious articles about it.

Some of the concerning coverage of my post was on vampire fan websites that no longer exist online. A decade ago I remember discovering a vampire fan website for teenage girls with a domain that may have been iheartvampires.net that made a serious two minute “vampire news” video about my “research” in vampire population dynamics that supposedly proved that vampires could not exist. The host discussed my blog post like it was real research. I was disheartened by this. I would like to engage teenage girls about operations research and analytics but without the vampires. It’s only fun if it gets people more engaged with real research, science, and engineering.

A positive example is the one entitled “Vampire Ecology: Twilight vs. Buffy” on a science blog that argues that vampires could exist by linking to another tongue-in-cheek paper that takes human predation on vampires into consideration as a form of vampire population control. It doesn’t seem to take my post too seriously (phew).

I have given a lot of though to increasing scientific literacy in the general public for the last decade. The far-too-serious coverage of my silly vampire post did not dissuade me from engaging the public about my research. Instead, it encouraged me to be more intentional with how I communicate scientific principles to the public and motivated me to discuss real scientific issues with the general public as much as I can. I have blogged about some of my public talks and have appeared in the media many times. I have found that a lot of people are receptive to science and engineering research, especially if it seems relevant to their lives. I try to stick to applications of operations research, analytics, and industrial engineering in the public sector.

I’ve been encouraged by the discussion of real scientific principles during the COVID-19 pandemic. It’s been a positive side effect of a serious pandemic. I hope the public’s interest in science continues.