The common conception of forgetting is that it is a bad thing. But a wide range of research shows that forgetting and the inability to remember/recall aids learning and human intelligence. For example, a recent paper argues that:
Rather than being a bug, forgetting may be a functional feature of the brain, allowing it to interact dynamically with the environment.
In a changing world like the one we and many other organisms live in, forgetting some memories can be beneficial as this can lead to more flexible behaviour and better decision-making. If memories were gained in circumstances that are not wholly relevant to the current environment, forgetting them can be a positive change that improves our wellbeing.
In other words, “we learn to forget some memories while retaining others that are important”.
Forgetting and limited memory aids learning
The importance of forgetting in learning is not a novel idea. It is well known that re-learning is more beneficial if the re-learnt items had been forgotten before the re-learning. For example, inducing forgetting via a change in environmental context enhances learning. The spacing effect and the success of spaced repetition as a learning strategy depends upon this simple insight.
The importance of limited memory in learning has also been highlighted in a study by cognitive scientist Jeffrey Elman. Elman demonstrated that under certain conditions, initial restrictions on the memory of an artificial neural network may improve its ability to comprehend complex grammatical relationships. In Elman’s words:
one might have predicted that the more powerful the network, the greater its ability to learn a complex domain. However, this appears not always to be the case. If the domain is of sufficient complexity, and if there are abundant false solutions, then the opportunities for failure are great. What is required is some way to artificially constrain the solution space to just that region which contains the true solution. The initial memory limitations fill this role; they act as a filter on the input, and focus learning on just that subset of facts which lay the foundation for future success.
In the same manner, an infant’s limited memory capacity acts “like a protective veil, shielding the infant from stimuli which may either be irrelevant or require prior learning to be interpreted”.
Solomon Shereshevsky and Funes the Memorious
The most striking example of how perfect memory can cripple human intelligence is the case of the Russian journalist and mnemonist Solomon Shereshevsky. The Soviet neuropsychologist Alexander Luria studied Shereshevsky for over thirty years and found that he possessed a memory of almost unlimited capacity and durability. Luria tested Shereshevsky’s memory by asking him to repeat arbitrary series of numbers, words, and syllables that Luria had provided him. Shereshevsky completed this task without error no matter how long the series and how long back Luria had given the series to him. Shereshevsky possessed a flawless recollection of data Luria had given him as long as 15 years ago. In many respects, his mind resembled that of a computer. When asked to reproduce a particular word in the series, Shereshevsky “would pause for a minute, as though searching for the word” as if he were searching through a vast database.
Perfect memory, however carried a high cost. Shereshevsky struggled to understand the meaning of simple passages of text (especially poetry or metaphors), “a struggle against images that kept rising to the surface of his mind.” He found it almost impossible to extract any true meaning from them or to be truly aware of anything at an abstract level. In this respect, Shereshevsky resembled Jorge Luis Borges’ famous character ‘Funes the Memorious’, whose prodigious memory meant that he was “incapable of ideas of a general, Platonic sort”.