What’s an earworm? Well, it’s a wee beastie or an obscure British record label. But in my friend Rod’s usage, it’s a song that get stuck in your head and doesn’t go away. Research is being done into the science of earworms (link via Girlhacker):

Perhaps persistent songs are like recurring dreams, she says: "Something in the back of your mind is trying to tell you something." As proof, Deutsch cites her own experience. Whenever she can’t get a song out of her head, she contemplates the meaning of the lyrics—and the song instantly goes away. "Even songs without words can have a larger meaning," she notes, mentioning anthems and religious music as examples.

OK, but what if the tune circulating in your skull is the theme from "The Flintstones"? What’s the deeper message behind that? Deutsch isn’t sure, but insists that if the human brain has a tendency to play songs over and over, there must be an evolutionary reason.

I’m not at all convinced by the idea that there’s some sort of deeper meaning communicated by the songs you can’t get out of your head. I recently read an article in Lingua Franca about an evolutionary theorist who thinks art is an evolved behavior (link via Kathryn’s Dear Internet Abyss). That sort of evolutionary psychology explanation may explain why the distress calls of ants (link via the always fascinating Honeyguide) sound eerie to me — because it’s foreign to the Pleistocene environment in which human behavior evolved — and the sound of rain is soothing. But does it explain why I can’t get "Jeremy" or that thrice-damned Creed song out of my head when I hear them on the radio?

Maybe, maybe not. The other suggestion made about earworms is that they tend to have unusual time signatures or be especially rhythmic. One of my guiding beliefs about the human species is that people are pattern-seeking — that is, people attempt to parse the sensory input, looking for repetition to make some sort of sense of it. It’s excellent stuff when used, say, by the Secret Service to pick out behavior from crowd members that doesn’t match what they’ve observed in years of studying crowds. It’s less excellent when it causes Babe Ruth to eat pickled eels (although one can hardly argue with the results; as the joke goes about the woman in Milwaukee waving her arms to keep the tigers away, "See? It’s working!"). The late psychologist Amos Tversky spent his career studying the Wonderland logic of human decision-making. His most famous experiment may have been on the heuristics of judgment: demonstrating, for instance, that people, given a brief description of the college-educated, social activist Linda, found it more credible that Linda was a feminist bank teller than that Linda was a bank teller. But Tversky was also a student of human perception; he argued that there is not such thing as a "hot hand" in basketball in a paper which has generated continuing disagreement from people who believe in streakiness. Instead of hot streaks, he argued that coaches, good little pattern matchers that they are, look for an explanation for inherently random events.

It’s easy to imagine why this behavior would have been useful for our evolutionary ancestors; it’s less useful for situations in which a slight change in background noise probably doesn’t mean that a leopard is lurking in a tree. And writing catchy songs is hard; I’m still not quite sure how a simple set of rules makes one song forgettable and one song nauseatingly catchy.

And nauseatingly may be the right word; my apologies to you, gentle reader, if you now have Eddie Vedder’s voice echoing through your skull. Unless you’ve infected yourself deliberately (like the protagonist of Bester’s The Demolished Man, who confounds telepaths by getting hit with an earworm that goes, in part, "Tension, apprehension, and dissension have begun"), and you probably haven’t, I’m sorry to report that, according to the L.A. Times article, no foolproof cure for the common earworm is currently known.