We all know how frustrating it is to forget something we’ve learned, whether we’re trying to recall it for an exam, a conversation or for ourselves. Our brains are estimated to hold between 10 and 100 terabytes of information! So what causes us to forget certain memories and facts? Have we figured out how to retrieve them?
Hermann Ebbinghaus was an ambitious nineteenth-century German psychologist who set out to find the answers to our questions about forgetting. Working as both the experimenter and test subject, he committed himself to learning and memorizing 2,300 nonsense syllables, such as “bov,” “wug,” and “koj.” They were all three-letter syllables that could be pronounced, but not associated with anything concrete or recognizable. Facebook and Twitter were not around to distract him, so Ebbinghaus was able to spend several hours straight a day reading a random selection of his nonsense syllables aloud in order to encode them into his memory. At the end of this study period, he tested his ability to recall each selection by recording the syllables into a notebook.
Recalling the syllables immediately after learning them was no challenge for Ebbinghaus; his test score was a perfect 100%. Next, he increased the amount of time that passed between the end of the study period and the test. When he tested himself just twenty minutes after learning them, his ability to recall the syllables had already decreased to 58%, and two hours after learning them, it was down to 36%! When Ebbinghaus waited 31 days to test himself, he was able to recall 21% of the syllables. From this, he learned that the loss of information was very sharp initially, but the 37% loss of retention between 20 minutes and 31 days suggested a slowing curve. Thus, Ebbinghaus created the Forgetting Curve, which highlights the importance of time as a factor in retention.
Outside of Ebbinghaus’ syllable test, the percentages of retention in the Forgetting Curve would not be sufficient to pass an exam or have a productive discussion with. But we can now consider methods for improving them. And this is what drove Ebbinghaus to discover that our ability to retain information also depends on the level at which we process it. Nearly a century later, psychologist Craik and Lockhart explored that discovery further and concluded that there are two unique levels of processing: Shallow Processing and Deep Processing. Shallow Processing supports short-term retention, which can be achieved through repetition of the structural (physical appearance) and phonemic (sound) properties of the information. In Ebbinghaus’ experiment, this would mean memorizing the syllables by remembering the shapes of the letters (i.e. curves, lines, apertures) and the way the syllable sounds when read aloud. Deep Processing should be employed to create durable, long-term memories. By linking new information with previous knowledge, you are increasing your ability to recall it later. If you want to perfectly recall a list of syllables that you have not looked at in 31 days, you cannot simply study their appearance and sound. You must associate them with something you already know (i.e. another word, image, idea, feeling, story).
Why was it important that Ebbinghaus’ experiment consisted of purely nonsense syllables? He was ensuring that no syllable would lead to a stronger memory than another. If a syllable could be associated with previous knowledge, this would create a meaningful connection that makes it easier to recall than other syllables. What connections could you make to remember the syllable “tog”? Does it make you think of longer words like “toggle” or “together”? Do these longer words make you think of sentences you’ve seen or heard them in before? What about “koj”? This should be more difficult.
When you connect the information you’re learning with things you’ve already learned, you reinforce it, improving your ability to retain it both short- and long-term. This is useful in all realms of learning, whether you are preparing for an exam, learning the ropes for a new job, teaching yourself a foreign language… you name it! Improve recall for an exam by working through practice problems or making diagrams of the information you’ve learned. Prepare for a job by simulating situations that require application of the new information. Deepen your understanding of new foreign language vocabulary by using it in sentences with words you already know. A memory is strongest when you weave it into a preexisting system of knowledge!