We talk about “memory” as if it is one thing, but actually memory is a combination of systems that sometimes work together. This lecture defines the different systems.
These notes are part of a series for the course.
As discussed in the previous lecture, there are several memory systems. But, when people say they want to improve their memory, they usually mean their episodic memory. When people say they can’t remember something, they usually mean they are having a problem with memory retrieval, which is dependent on how the memory was encoded.
Trick for remembering: the method of loci
One old trick that survives from ancient Rome is called the method of loci. “Loci” means place. In ancient Rome, messengers would travel from one town to the next to spread news and information across the provinces. They knew their traveling routes well, and so they would mentally associate the things they needed to remember with points along their routes.
For example, let’s say on your way to work you go through 10 main intersections (or pass notable business or buildings, and so on). If you travel this route to work every day, you know it well. Now let’s also say you need to remember your grocery list, which changes every week. For this week, you need bananas, beans, and rice. You can make a silly mental picture that associates bananas with the first intersection on your route (for example, driving through the intersection you run over a bunch of bananas); beans with the second landmark (for example, after the first intersection you pass a school — which is filled with beans), and so on.
For best results:
- Make it ridiculous, bizarre, silly — the sillier, the better for remembering later.
- Create a mental picture of it as you go along.
When you need to recall your weekly grocery list, you think back over the memory you’ve created of you traveling on your route to work… along with the silly things you saw with your needed groceries.
The “memory palace” variation: This is the same concept, but instead of remembering a route you travel, you remember a (real or imagined) house with many rooms and lots of details.Spend a week or more really imagining this place and all its details, and then you can use your memory palace in lieu of the route for the method of loci.(In the BBC show Sherlock, Sherlock Holmes uses the memory palace variation of this trick.)
See also: The lecture doesn’t mention this, but I think the memory palace variation is based on a technique shared with us by Marcus Fabius Quintilian (who lived about 35 – 100 CE), in section 11.2 of his Institutio Oratoria .
Why it works: encoding, dual coding, and memory retrieval
This trick works because you are encoding a new memory (your grocery list) by connecting it to knowledge you already had (your route to work). When you are piecing the two memories together, you are doing so within working memory.
We remember bizarre things best. And, when we create a mental picture, we’re storing the words (bananas, beans, rice) as words in the part of the brain that deals with words, and the picture (running over bananas with your car, a school filled with beans) in the part of the brain that deals with images. Storing it it two places is called dual coding, and that increases our ability to retrieve the memory later.
One of the questions we’re asked to consider is why everyone doesn’t improve their memory, since it’s possible. I think the question is there as a way to prod you to the next lecture, to help you convince yourself that you should busily create a memory palace of your own. But, it maybe also hints at a few other things:
- Do we hold onto memories that we shouldn’t? For example, people who have lived through traumatic events may replay those memories over and over in a way that is not healthy or helpful for them.
- Is there a limit to what we should do to improve our memory? What if it could be improved by implanting a chip, is that a step too far from the memory palace, or does the same argument apply (that we can do it, so why not?)
- Is it possible that our memory works and forgets in a way that’s beneficial to us, even if we don’t understand why?
- If we become enamored with our parlor tricks of remembering long lists of unrelated items, will we lose sight of the difference between memory and learning, or memory and knowledge?