“It’s terrible,” Claudia lamented, “my memory is like a sieve. Whatever I pour into it, it just trickles through.” She can’t understand how her sister Brigitte brings home just as good – if not better – grades with much less studying. She has the feeling that she is much more diligent. When Brigitte repeats vocabulary ten times, she does it at least twenty times. When her sister repeats a poem twenty times, she does it forty times.
More than a hundred years old is one of the strangest findings of psychological learning research, which, despite its venerable age, receives surprisingly little attention: The forgetting curve.
Herrmann Ebbinghaus discovered it around 1885 and examined it more closely in many experiments. He found that after the first laborious learning of a poem, it is then unfortunately not yet finally and permanently stored in the brain. Quite the opposite: If one leaves the poem now to its fate and examines it approximately after one hour, on the average about half is again disappeared. So every new, freshly memorized content seeps away with considerable speed somewhere between our brain convolutions. And this goes on and on. Although the curve fortunately soon becomes somewhat flatter with time, on average no more than about one fifth actually remains in memory.
This natural “evaporation tendency” of freshly learned content was probably known before from observations of everyday learning situations, and a number of methods were developed to prevent newly learned content from seeping away. The most obvious one was – as Claudia did – not only to learn until one has “just about” mastered a new content, but to continue cramming, i.e. to repeat the learning material five, ten or even twenty times more often than is actually necessary and to hope that this “overlearning” will reduce memory loss.
This strategy, which seems so obvious, is unfortunately completely useless. He was able to show that people who learn a content only until they have just mastered it, and other people who subsequently make a large number of further repetitions, can reproduce almost the same amount the next day.
But how can the considerable loss of a newly learned content be prevented? Only one strategy helps here, which has been known for a long time but is rarely really followed: Regular repetition, whereby the emphasis here is not on repetition but on regular, and according to the rule that the forgetting curve gives us!
Without impatience we first leave a newly learned content to its fate and consciously accept that a part of it will be lost. After a suitable time – preferably when a little less than half of the material has “evaporated” – we perform a first repetition and bring the entire material back to the level of one hundred percent mastery – in order to then put it aside again and leave it to oblivion.
For now a pleasant regularity comes to us: Although some parts of what has just been repeated will be lost again, the decline of the forgetting curve is now no longer as steep as after the first learning. The “half-life” has become much longer and we can let a much longer period of time pass – perhaps half a day – before we catch the lost content again with another repetition. In this way, we can schedule short periods of repetition in longer and longer periods of time and prevent the memory loss that is inevitable in any other way.
So we can recommend Claudia not to put her energy into overlearning, but to better spread the learning times over a longer period of time. We can’t outsmart the forgetting curve with heaped repetitions. On the contrary, it is much better to learn only until we have just mastered a new content. With a total of four or five repetitions – which will always be shorter, since we need less time each time to get back to one hundred percent – we ensure that the material becomes permanently embedded in our brain. That’s why some people, like Claudia’s sister Brigitte, don’t learn more than others, but divide up their learning more evenly.