Three things inspired this. The first was some passages in Joshua Foer's book Moonwalking with Einstein, in which he looks at the techniques that Ben Pridmore and other memorisation champions use to memorise such remarkable quantities of information. In Chapter Five, "The Memory Palace", Foer notes that the point of memory techniques is to transform the information we want to remember into a form that our brains were built for. And apparently, one of these is navigation. Foer quotes the Memory Grand Master Ed Cooke:
"The thing to understand, Josh, is that humans are very, very good at remembering spaces," Ed remarked from his perch on the boulder. "Just to give an example, if you are left alone for five minutes in someone else's house you've never visited before, and you're feeling energetic and nosy, think about how much of that house could be fixed in your memory in that brief period. You'd be able to learn not just where all the different rooms are and how they connect with each other, but their dimensions and decoration, the arrangement of their contents, and where the windows are. Without really noticing it, you'd remember the whereabouts of hundreds of objects and all sorts of dimensions that you wouldn't even notice yourself noticing. If you actually add up all that information, it's like the equivalent of a short novel. But we don't ever register that as being a memory achievement. Humans just gobble up spatial information."
This made me wonder whether I could improve my memory for the things I was drawing by thinking of them not as single and relatively small objects, but as landscapes that I wanted to navigate.
My second source of inspiration was the Oxford Centre for Human Brain Activity research on attention and memory that I blogged in "Attention restores forgotten items to visual short-term memory". As I mentioned in that posting, the research suggested to me that when sketching someone who I've only seen briefly, then about a second after seeing them, I should deliberately scan my remembered visual field. And I should pay attention to those places in it where I think the most salient details for my drawing are. The division into numbered regions that I'm writing about today prepares for that scan, and the numbers make sure that I scan everything.
The final inspiration was the idea of a memory palace. It's the main memorisation technique that Foer writes about, but was known long before him, dating at least as far back as the ancient Greeks and Romans. The idea is to first build a mental image of a palace or other building. Then become so thoroughly familiar with it that you can reliably walk through it, guaranteeing to visit all its rooms or landmarks in a fixed sequence without missing any. Once you've done this, your memory palace is ready for use. To memorise a list of items, mentally place one item in each room. There are lots of techniques for converting hard-to-visualise items such as abstract concepts into images that are easier to visualise, and for associating them with the room they're in. To recall a list, just walk through the palace and see what's in each room.
Here's a sketch made using the method described in my first paragraph. I think it worked well, given that I drew it entirely from memory, something I don't think I could have done otherwise.
It's a man who I was watching from inside Combibos, standing near a Saturday market stall being set up in Gloucester Green. I haven't kept a note of how many numbers I superimposed, but it would have been around eight. Two went on his head: one for the quiff, and one for the rest of his hair. One was for his face and neck, including prominent eyebrows and the different length sides of the V below the neck, plus the change in direction of the collar further up. One was for his further arm, and one for the torso and nearer arm: the amount of visible back to the right of his arm was important, and I may have used negative space to judge this. And probably two regions were for his legs, with special attention paid to position of feet and to the stretch creases along his nearer leg. To make the perspective right, the bottom of the nearer trouser leg should probably have been lower.
Granted, the drawing looks stiff. This is partly because I was being quite deliberate when I drew the lines, not thinking about how to change their character to reflect what I was drawing. So the man's hair was drawn with the same simple straight line as his sleeves and trouser legs, even though one would have had a fine texture, one would have been gently undulating, and one would (if denim, which statistically speaking, it probably was) have been full of inelegant wrinkles and bulges. My memory didn't extend to that level of detail.
In drawing this and other sketches, I was thinking almost entirely about numbered regions. Even though the idea was inspired partly by Foer's passage about landmarks and navigation, I wasn't changing mental contexts to think of this as navigation. Would that have helped?
I haven't objectively tested this memory technique, so although it seems to work, that could be self-delusion. If it does work, it needs practice. Part of that, I've found, is being able to superimpose a constellation of numbers in parallel, because there isn't always time to work through them one by one. I think it also needs some prior experience in drawing, so that you know which features of the subject will be most useful in helping the viewer "read" your sketch, and hence should be paid attention to.