Jack, Jill, and a LionPublished 9 November, 2010
Once upon a time, Jack and Jill found themselves on an island. Every day, each of them had to decide whether to go into the forest to pick fruits, which were good for them and they liked very much, or stay by the beach and dig up tubers, which were starchy, bland, and had few nutrients. The problem was that sometimes a lion roamed the forest, making it more dangerous. So, while the fruits were tastier and more nutritious, collecting them came with a risk.
Now, since this is just a story, we’ll make the forest magical. Whenever the lion was in the forest, the leaves of the trees turned blue.
Now Jill, being clever, used a very simple method to choose when to go picking fruit in the forest. She only went when the leaves were green, meaning the lion was elsewhere. So, Jill sometimes got fruit, and sometimes had to settle for tubers, but never got eaten by a lion.
Jack, however, was even more clever than Jill. He was so clever, he decided to believe, incorrectly, that the leaves were always blue, and that the lion was always in the forest. So, he never went picking fruit, and had to settle for tubers all the time.
What’s wrong with this story is, obviously, that Jack isn’t clever at all. In fact, if Jack and Jill reproduced asexually, clearly Jill would leave more offspring, being nourished by fruits as opposed to just tubers. Jack is very obviously at a severe competitive disadvantage.
Ok, that’s really clear, but my point really has to do with this argument in the context of a recent article in the Globe and Mail which reports on some interesting research by Jesse Bering. The upshot of the work is that people who think that a supernatural agent is observing them don’t cheat as much. Bering’s argument, which he’s made elsewhere, is that belief in supernatural agents is evolutionarily advantageous because these beliefs make you less likely to cheat.
I am very fond of the people who have been making this argument, but I confess it seems illogical on the face of it. Just like Jack, who doesn’t take advantage of picking fruits when there’s no lion about, people with false beliefs about being observed and punished by supernatural entities don’t take advantage of the opportunities they would have if they didn’t have their incorrect beliefs. (I’m assuming that supernatural agents don’t exist, and, even if they did, that they punish people only after the person in question has had whatever reproductive success they’re going to have, making punishment in the afterlife irrelevant in the fitness sense.) It’s good, not bad, in the evolutionary sense, to cheat if the expected value of cheating is higher than the expected value of not cheating in the same way that it’s good, not bad, to go picking fruit when the lion sleeps tonight or whatever.
I do not see any way around this problem. The idea that believing in supernatural agents is an advantage because it causes you to make worse decisions doesn’t make any sense to me. Very generally, false beliefs tend to be bad for good decision making. But then, maybe it all makes sense if you read the book…