The Case of the Unexplained Band-Aid (or Why Sherlock Holmes Was Wrong)

6jHVxThis morning I woke up to find a Band-aid stuck to a desk in my brain.

Why was it there? It was a large, important looking Band-aid, stuck right across the sparkling clean surface of my desk. I couldn’t remember putting it there, but sometime last night I must have walked in, stuck the Band-aid to the surface of the desk in my brain, and walked out again.

I went out with a couple of friends last night and drank two and a half beers, which is a lot for my pathetic constitution, so I don’t remember too well what I was thinking. And that’s what makes the Band-aid on the desk in my brain so fascinating.

If you have watched the BBC series Sherlock, you probably already know where this desk is. It’s furniture in an imaginary room inside my head, part of what is popularly known as a “memory palace,” or what the Greeks and Romans called the “method of loci.”

The method of loci is a memory technique, leveraging the remarkable power of spatial and visual memory. Classical orators, struggling to remember long speeches, discovered an important fact about the human brain: remembering words and abstract concepts is difficult; remembering pictures and places is easy. To aid in memory, they created imaginary spatial locations (“loci”) in their minds, and visually placed mnemonic aids there. They discovered that when they returned to the same mental location, the visualized object would still be there. If they built hundreds or thousands of spatially related loci, they could store hundreds of thousands of facts. Some built whole palaces inside their heads to store information.

Ironically, Sherlock’s use of a memory palace in the BBC show is entirely at odds with the literary Sherlock Holmes, who believes that memory is intensely limited. He tells Watson, in Conan Doyle’s book:

“I consider that a man’s brain originally is like a little empty attic, and you have to stock it with such furniture as you choose. A fool takes in all the lumber of every sort that he comes across, so that the knowledge which might be useful to him gets crowded out, or at best is jumbled up with a lot of other things, so that he has a difficulty in laying his hands upon it. Now the skillful workman is very careful indeed as to what he takes into his brain-attic. He will have nothing but the tools which may help him in doing his work, but of these he has a large assortment, and all in the most perfect order. It is a mistake to think that that little room has elastic walls and can distend to any extent. Depend upon it there comes a time when for every addition of knowledge you forget something that you knew before. It is of the highest importance, therefore, not to have useless facts elbowing out the useful ones.”

The Greeks and Romans, however, knew that Sherlock is wrong. The walls of memory are elastic, and the breadth of human memory is almost boundless. Well organized human brains are capable of staggering feats of memorization, such as learning tens of thousands of digits of Pi by heart. The trouble is not storing all those memories; it’s retrieving the right memory at the right time. And that’s where the memory palace comes in.

My “memory palace,” however, is just a humble room. It is sparkling white and clean, and glows with a soft, pleasant light. Against the far wall sits a white, wooden writing desk and a bookshelf. On the right-hand wall hangs a whiteboard.

The effectiveness of the method of loci is, at first, downright eerie. We are accustomed, I think, to imagining memory as something over which we have control, and our minds as familiar places. The method of loci shatters that illusion by showing us that we can put things in our memory, forget we put them there, and yet find them the same place the next day. It shows us that there are vast reaches of mental space that still exist even when we are not looking. It’s a little like realizing that your home has a false wall, and behind it lurks a vast warren of tunnels you never knew existed, inhabited by who-knows-whom. Or perhaps like waking up and finding a note, written in your own handwriting, stuck to the mirror by some Mr. Hyde doppelganger.

And that’s why I find the Band-aid so interesting. When I woke up this morning, I had no memory of trying to remember something, and no memory of the fact I was trying to remember. But when I walked into my room, there it was, clear as day.

Also, I should note, the letters “$28” were written neatly on the whiteboard. That, however, was obvious — I was recording the bill for my meal and drinks because, since the bill came on one slip, I didn’t get a receipt.

It took me about five minutes to figure out what the Band-aid meant, or rather for the meaning to come to me, since there was no real “figuring” involved. The meaning just popped to mind. Last night, my friend told me about a colleague doing cutting edge research into blood clotting. I thought that was interesting, thought I might write a story about it one day, walked into my room, and stuck a Band-aid to the desk.

And there it was the next day.

This article is one of a series on memory. Interested? Read my post on memorizing the countries of the world.