A theory of earworms

Freezepop’s Memory Disappears got stuck in my head for a few days back in 2021 when I first heard it. It’s a lovely song, so this was a fairly pleasant experience. In particular I had the first four lines of the chorus in my head:

They save it for a while
Memory on file
The machines won’t look back
Why should you?
They save it for a year
‘Til your memory disappears
All their tapes will corrode
Why should you?
Why should you?

But I hadn’t heard the line “All their tapes will corrode” properly and I didn’t really know what she was singing there, and so I looked it up. After I’d looked it up, it was that line that was coming into my head. So it was as if my brain had decided that it was happy with the first part, but that it needed to solidify the second part.

As a result of that, I came to a theory of why music gets stuck in our heads: it looks to me like it’s an evolved mechanism to help us learn songs. This would have been valuable in an ancestral environment in which songs were a way to strengthen group coordination.

This theory produces some potentially testable predictions:

  • Hearing a song several times in succession, which would be an indication that it’s part of your group’s culture, would make it more likely to get stuck in your head. (And it may be that repetition within a song is a way to fake this signal.)
  • Hearing a song in a context that suggests social significance (e.g. dancing to it with friends in a club, or even just with a DJ announcing it on the radio) would make it more likely to get stuck in your head.
  • Once you know a song well, it’s less likely to get stuck in your head.
  • The parts of a song that will get stuck in your head are the novel parts, as in the Freezepop example above.
  • If you haven’t heard a song for a long time and have forgotten how it goes, hearing it again will cause it to get stuck in your head.

There’s also the common phenomenon in which when you first buy a new album you play it to death for the first few days, and then you fairly abruptly cease to be interested in it. This would also fit the theory.

I imagine that all of this should apply to poetry too. And sometimes I find that names and words sometimes echo repeatedly in my head. It’s not surprising that sometimes a name should seem important, particularly in a social context, and therefore valuable to learn.

Perhaps it applies to other aspects of memory as well. I think it’s fairly clear that memory isn’t a static thing where we simply store recordings and information for later retrieval. There’s clearly an active part of it too. To what extent is thought a rehearsal of things that we wish (not necessarily consciously) to learn or remember? The Tetris Effect might well fit this pattern.

I haven’t done any research into this area beyond reading the Wikipedia page on earworms. I don’t know whether this is an original idea or not, though Wikipedia doesn’t mention anything like it. And I haven’t given much thought to counter-evidence. So I’m holding this idea pretty lightly at the moment. I’d be curious to hear whether there’s been any work in this area.