Hack 86. Change Context to Build Robust Memories
When you learn something, you tend to store context as well. Sometimes this is a good thing, but it can mean your memories don't lend themselves to being recalled in different circumstances.
This situation should sound familiar to almost all of you: you're trying to remember the name of the guy who wrote that book you read at some point in the not-too-distant past. You can't remember his name, but you can remember that he's a Canadian who moved to the United States and also writes about politics and has affairs with minor celebrities. You had a copy of the book about 5 years ago, the cover was reddish, and you packed it into a box when you moved and haven't seen it since then. You remember reading the book in the old café that they've since turned into a video rental store. You remember an amazing amount about the book and loads of information associated with it...just not the name of the guy who wrote it. What gives?
Often, you don't know in advance what details you need to remember for later recall. There aren't any clean boundaries between relevant and not relevant, and there are no tags reading "You will be tested on this later." So instead of remembering only what you choose to learn or are sure to need later, your brain files away many intricate details of context.
To you, this is just the context, but in your memory, it isn't necessarily sharply defined as such. Your memory is a set of interlinked and interleaved representations [Hack #87], so that in a fundamental sense the context can be part of the memory as much as the thing intended to be learned is part of the memory.
One consequence of this is that reinstating the original context helps you recall what you originally learned in that context. Another is that any consistent context associated with the learned item will become part of the memory for that item. Sometimes this can be a good thing, as is the case when you're trying to recall details you didn't know were going to be useful at the time or when you are trying to reproduce a skilled behavior in exactly the same circumstances in which you learned it. Other times it can hinder your recall of the memory in isolationwhen you're out of that context.
9.7.1. In Action
Here's an example of how the automatic encoding of context affects learningin this case, skill learning (skills are memories too). It's called the contextual interference effect, and it goes like this: practicing a collection of skills in a random order is better than practicing them in runs.
So, for example, if you are learning Japanese, writing each character of the hiragana (one of the three alphabets used in Japanese) is a separate motor skill. So it might be better to practice your hiragana by writing all of them out together, rather than copying out a hundred copies of one character, then a hundred copies of the next, and so on. You learn slower this way, but you remember better.
Ste-Marie et al. used this technique when teaching grade two students handwriting, practicing writing the letters h, a, and y.1 After writing each letter only 24 times, the students who practiced the letters in a mixed-up fashion had better handwriting (i.e., better motor memories) than the students who practiced in blocks, as soon as the very next day. You can acquire new skills more effectively even after this short a time.
Even better, skills you have learned like this transfer better to new situations. If you learn by repeating the same skill again and again, you're going to learn it in the context of repetition rather than how to do it one-off. Practicing with a series of one-offs means you learn in many different contexts, and the memorized skill is more sharply defined. It's easier to recall and apply to a new context because it isn't interwoven as tightly with the learned context.
9.7.2. How It Works
Most of the research on the contextual interference effect has involved simple motor memoriesthese are skill memories, the kind you use in throwing Frisbees, juggling, or swinging a golf club.
The effect is generally found only for skills that require significantly different movements from each other. So, for example, you see a contextual interference effect if you mix practice of throwing underarm and overarm, but not if you mix practice of throwing a ball underarm exactly 2.7 meters and practice of throwing a ball underarm exactly 3.2 meters. The skills in the first example use the muscles in different combinations and with different relative timings. Separate motor memories are created for the movements. In the second example, the two skills are just parameter-adjusted versions of the same motor memory.
The contextual interference effect works only if you have some degree of experience in the skills you're practicing. To run into a contextual interference effect, the rough framework of the motor memory must already be established. For example, when you first start learning the Japanese alphabet, you don't even have a skill you can practiceyou draw each character very deliberately (and badly!) and do it differently each time. Later, when you've learned the rough shape of the character and are beginning to produce it automatically, the rate at which you can improve the skill becomes open to the contextual interference effect.
One possible cause of the contextual interference effect is that interleaving the practicing of different skills requires concentration. It's certainly true that mixed practice is less boring, and we tend to remember less boring things more easily. But this also begs a question: interleaved learning may be better because it prevents boredom, but why does monotony bore us in the first place? Maybe boredom is the mechanism our brain uses to make us provide it a sufficient variety of input for optimal learning!
But the main cause of the effect is that random-order learning softens the brain's normal tendency to encode context along with the core memory. Usually this is a good thinglike when you are trying to recall where you first heard a song, met a person, or who wrote a book you once readbut it can prevent us forming sharp edges on our memories and reduce our ability to recall and use them in different situations.
9.7.3. End Note
9.7.4. See Also