Zombies and Zahavis

Over the past weekend, I participated in a Zombie Run. This is relevant to evolutionary psychology. Wait for it…


Rob Zombie.

Here is the way the Zombie Run works. There are humans, and there are zombies. Humans run the 5k course with three balloons that are attached to belts. (I am pictured here with one balloon.) Zombies – people dressed up for the part – are scattered along the course, and their goal is to pop the balloons on the belts of the human runners. When all three balloons are gone, the human is “dead.” Humans, of course, try to finish the course with as many balloons left as possible, but having even one left means you survived.

(Note: humans with three popped balloons do not become zombies, as, in some sense they should, given traditional zombie lore. If that were the rule, and “dead” humans became zombies, I’m pretty sure that everyone would be a zombie by the end of the course because zombies would be proliferating so quickly. Anyway, if you lose your last balloon, you just finish the race, and by and large the zombies just leave you alone. This actually introduces a strategic element insofar as a “live” human with a balloon in the small of their back might be mistakenly taken for dead by zombies, making dodging them easier.)


Start of Zombie Run, Philadelphia

At the start of the race, humans inflate their three life balloons and attach them to their belts. And here’s where the relevance to evolutionary psychology comes in. Popping a big balloon is easier than popping a small balloon. The large balloons extend out further from the runner’s body, making them easier to grab. They are also more difficult to hide; small balloons were occasionally obscured by runners’ arms or clothes. And, of course, larger balloons are stretched out more, so they are thinner.

There were no rules, as far as I found, regarding how far you had to inflate your balloons. Indeed, I saw some runners with some anemically inflated balloons, drooping limply from their belts. Most runners inflated their balloons to a middling size. (You can see some of them in this image from the start of the race.)

As I continued to race, I noticed a few people had inflated their balloons to the extent that they were noticeably larger than others. And then I saw a balloon inflated so large it must have been near to its natural popping point, which seemed puzzling at first. Why make your balloon so easy to pop? And that, of course, reminded me of passages in The Handicap Principle by Zahavi and Zahavi, such as this one, about a predator, in this case a merlin, trying to catch a prey item, such as a skylark:  

Rhisiart found that when the skylark sings while fleeing, the merlin is likely to abort the chase. When the lark does not sing, the merlin is more likely to continue the pursuit and is often able to catch the lark.

What could be the connection between the song and the chase? If we assume that some larks are faster than the merlin and some are slower, it makes sense for the merlin to try to select and chase individuals it can overtake. It is also in the interest of a skylark that flies faster than the merlin to let the merlin know that it cannot be caught. To convince the merlin of its superior abilities, the skylark must do something that a slower lark would not be able to do. Singing while flying is a good indicator of the lark’s abilities, since it displays the bird’s capacity to divert a part of its respiratory potential while still flying at least as fast as the merlin. A skylark that needs every ounce of strength it has to fly cannot sing at the same time. (p. 8).

I should say that I was unclear of the rules and details of the zombie run until I ran into the first pack of zombies. Would they have pins or sticks? Tools of any kind? Were they governed by rules? It turns out that zombies have to use their bare hands, but otherwise seemed to use whatever strategies they wished. Some zombies just stood around. Others were Defensive Back Zombies, who behaved like we were playing flag football and the runners had the ball. There were Stealthy Zombies, who jumped out from behind trees or other features on the trail. The worst were Pursuit Zombies, who would get in your way enough to make you dodge or sprint, wait a beat, and then turn to pursue you as you slowed down. (This is how I lost two of my three life balloons, both to a single Pursuit Zombie.)

This all had to be learned on the course. What I’m saying is that one possibility is that some people inflated their balloons without really knowing the disadvantages of having big balloons. Maybe.

But another possibility is that runners were using big balloons as a signal. Not, I think, to zombies, though my sense was that zombies took the big balloons as a particular challenge. I think that the signal was to other runners. In the same way that skylarks sing to signal their condition, I think big balloons are saying, hey, I can protect my life balloons from zombies even though they are big and easy to pop. As many readers of this blog will no doubt know, signals have value beyond the predator/prey dynamic above. Handicaps are also useful for signaling to rivals and, especially, mates.

So, for those of you teaching about signaling theory, this might be a nice example to use in class. It seems very intuitive to me, and students, generally, like examples to do with zombies, or really any of the undead, I find.

(Another aside. Runners quickly learn that there is safety in numbers. Being alone makes a runner very easy prey for zombies, who tend to be in little packs. People naturally in this environment reinvent herding as predator defense.)

There are zombie runs across the country. I’d like to know if there is a relationship between sex, relationship status, and balloon size. I predict that single males inflate their balloons the most, though there might well be other sorts of data worth gathering in this context.



Zehavi, A., & Zahavi, A. (1997). The handicap principle: A missing piece of Darwin’s puzzle. Oxford University Press.

10. April 2013 by kurzbanepblog
Categories: Blog | 1 comment

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