That’s what I came up with trying to remember the name “Mannheim Steamroller” last Christmas: Beethoven Hammer. I knew it was wrong, but I couldn’t remember the real name.

What was interesting to me, though, was why I came up with this. I could see that I had not stored the name “Mannheim Steamroller” in my memory directly, but had rather done something like “[German-sounding name] [Tool]” and then dispensed with the particulars. There are these weird moments when you can almost glimpse the architecture of your brain, and this was one of them.

I think we all probably do this: associate words with other words or ideas, fold preconceived or shortened ideas together into our memory without really understanding that we’ve done so.

Once, in college, I overheard a couple of guys chatting. One of them offered a vulgar joke about feminists. The other one replied vulgarly as well, but with an answer that only made sense when you realized he had understood “feminist” to mean “lesbian.”

We do this—of course—with our discourse on cities...