Reading passage Go to the questions
In praise of forgetting
A For most of us, forgetting feels like a failure. We search for a name that will not come, return to a room without remembering why, or sit in an exam hall while a carefully revised fact refuses to appear. It is natural, then, to think of memory as a storage system and of forgetting as a fault in it: information leaking away because the system is not good enough. Over the past few decades, however, a growing number of researchers have argued the opposite: that forgetting is not a weakness of memory but one of its most important functions.
B The scientific study of forgetting began in the 1880s with the German psychologist Hermann Ebbinghaus. Using himself as his only subject, Ebbinghaus memorised long lists of meaningless syllables, such as "DAX" and "BOK", and tested how many he could recall after different periods of time. The results, published in 1885, showed that much of what he learned disappeared remarkably quickly, a large part of it within the first day, after which the rate of loss slowed considerably. This pattern, now known as the "forgetting curve", has been reproduced many times since, and it remains one of the most reliable findings in psychology.
C For a long time, the forgetting curve was read as a measure of decay, as if memories simply faded like ink in sunlight. Yet later experiments suggested that forgetting is often more active than this. In the 1990s, the psychologist Michael Anderson and his colleagues showed that practising the retrieval of some items from a category can make related items harder to recall. A person who repeatedly recalls "banana" and "orange" from a list of fruit, for example, will later find "apple" more difficult to remember than someone who did not practise at all. Anderson's interpretation was that the brain suppresses competing memories in order to make the most useful ones easier to reach.
D Sleep appears to play a part in this selection process too. According to the synaptic homeostasis hypothesis, proposed by Giulio Tononi and Chiara Cirelli, the connections between brain cells grow stronger throughout the waking day as we take in new experiences. If this strengthening continued unchecked, the brain would require ever more energy and space, and new learning would become increasingly difficult. Sleep, they suggest, allows the brain to weaken connections across the board, so that weaker, less important traces are lost while the strongest survive. The idea remains a hypothesis and is still debated, but it offers a striking explanation of why a night's sleep so often leaves us clearer-headed rather than simply rested.
E Perhaps the most ambitious argument comes from the neuroscientists Blake Richards and Paul Frankland. In a review published in 2017, they proposed that the purpose of memory is not to preserve information as accurately as possible but to help us make good decisions. From this point of view, a memory system that kept every detail would be a disadvantage. In a changing world, out-of-date details can mislead us, and holding on to the specifics of individual events can make it harder to see the general patterns that link them. Forgetting, they argue, allows the brain to generalise.
F Literature offers a memorable illustration of this point. In a short story by Jorge Luis Borges, a young man called Funes is left unable to forget anything after a riding accident. He remembers every leaf on every tree he has ever seen, yet he cannot understand why a dog seen from the side at one moment should share the same name as the dog seen from the front a minute later. Borges suggests that thinking itself depends on forgetting differences.
G None of this means that every lapse of memory is beneficial, and conditions that damage memory remain a serious concern. But the new research does change the question that students and teachers might ask. Rather than trying to remember everything, learners may do better to decide what is worth keeping, and to revisit that material at intervals, just as the forgetting curve begins to fall.
