The Psychology and Philosophy of Memory

[Article revised on 27 July 2020.]

In Game of Thrones, Archmaester Ebrose says to Samwell:

'In the Citadel, we lead different lives for different reasons. We are this world’s memory, Samwell Tarly. Without us, men would be little better than dogs. Don’t remember any meal but the last, can’t see forward to any but the next. And every time you leave the house and shut the door, they howl like you’re gone forever.'

Later, during a war council, Bran Stark reveals that the Night King is after him because he is the Three-Eyed Raven that embodies the collective memory of mankind: ‘An endless night. He wants to erase this world. And I am its memory.’

‘That’s what death is, isn’t it?’ replies Samwell, ‘Forgetting, being forgotten. People forget where we’ve been and what we’ve done, we’re not men anymore, just animals…’

Memory refers to the system, or systems, by which the mind registers, stores, and retrieves information for the purpose of optimizing future action.

Memory can be divided into short-term and long-term, with long-term memory further divided into episodic and semantic. Episodic memory records sense experience, while semantic memory records abstract facts and concepts. The distinction between episodic and semantic memory is implicit in a number of languages in which the verb ‘to know’ has two forms, for example, in French, connaître and savoir, where connaître implies a direct, privileged kind of knowledge.

There is, naturally, a close connection between memory and knowledge. The connaître and savoir dichotomy is also pertinent to the theory of knowledge, which distinguishes between first-hand knowledge gained through direct sense experience and testimonial knowledge gained by the say-so of others, often teachers, writers, and journalists.

In the absence of first-hand knowledge, the accuracy of a piece of testimony can only be verified against other sources of testimony. Similarly, the accuracy of most memories can only be verified against other memories. For the vast majority of memories, there is no independent standard.

Episodic and semantic memory are held to be explicit or ‘declarative’, but there is also a third kind of memory, procedural memory, which is implicit or unconscious, for skills such as reading, slicing vegetables, and riding a bicycle. If episodic memory broadly corresponds to first-hand knowledge and semantic memory to testimonial knowledge, then procedural memory corresponds to know-how.

Although held to be explicit, episodic and semantic memory can influence action without any need for conscious retrieval or processing—which is, of course, the aim of practices such as advertising and brainwashing. Try though I might, I can only bring up a handful of memories from my holiday to Uruguay last year, and even fewer from the entire year 2010. Most of our memories lie beyond or beneath conscious retrieval, locked up in a dark dungeon with little chance of ever escaping.

Memory is mysterious, even miraculous: organic brain matter somehow re-arranges itself to encode experiences, facts, and procedures.

The most mysterious and miraculous type of memory is prospective memory, or ‘remembering to remember’. To ring my mother on her birthday, I must not only remember her birthday, but also remember to remember it. Whenever I forget to set my alarm clock, I find myself waking up just in time to make my appointment or catch my flight, even when I have slept only three or four hours. This suggests that, even in sleep, the mind is able to remember to remember, and able also to keep track of time.

Memory is encoded across several brain areas, meaning that brain damage or disease can affect one type of memory more than others. For example, Korsakov syndrome, which results from severe thiamine deficiency (most commonly associated with alcohol dependency) and consequent damage to the mammillary bodies and dorsomedial nucleus of the thalamus, affects episodic memory more than semantic memory, and anterograde memory (ability to form new memories) more than retrograde memory (store of old memories), while sparing short-term and procedural memory. Alzheimer’s disease on the other hand affects short-term memory more than long-term memory, at least in the earlier stages of the disease.

As a psychiatrist, I am often asked to assess people with dementia, making me all too aware of the importance of memory to daily life. To live without memory is to live in a perpetual present, without past and without future, going through the same thoughts, the same questions, the same fears, over and over and over again. Without any memory at all, it would be impossible to: speak, read, learn, find one’s way, make decisions, identify or use objects, cook, wash, dress, and develop and maintain human relationships. More fundamentally, it would be impossible to know anything, and therefore to reason—reasoning being the process of extracting knowledge out of knowledge.

Without memory, it would be impossible to build upon anything or engage in any form of sustained goal-directed activity. In Greek myth, the goddess of memory, Memosyne, lay with Zeus for nine consecutive nights, thereby begetting the nines Muses. As I argue in my new book, Hypersanity: Thinking Beyond Thinking, without memory, there could be no art or science, no craft or culture… and no meaning either.

Nostalgia, sentimentality for the past, is often prompted by feelings of loneliness, disconnectedness, or meaninglessness. Revisiting the past can lend us much needed context, perspective, and direction, reminding and reassuring us that our life is not as banal as it might seem, that it is rooted in a narrative, and that there have been—and will once again be—meaningful moments and memories.

Judging by the cost and logistics of a wedding and wedding photographs, we are prepared to go to great lengths to manufacture ‘anchor’ moments and memories. But people with severe memory loss can no longer revisit the past and may instead resort to confabulation (the making up of memories) to create the meaning and identity that they crave.

I once visited a nursing home in southern England to assess an 85-year-old lady with advanced Alzheimer’s disease. She insisted that we were in a hotel in Marbella: she was busy planning her wedding and wouldn’t have time to talk to me. When I asked her, ‘What did you do yesterday?’ she replied, with a twinkle in her eye, ‘I hit the town for my hen night and my friends spoilt me rotten with champagne and fancy cocktails.’

Bernard Ingram, Margaret Thatcher’s former press secretary, recently revealed that, after the Iron Lady developed dementia, ‘it was as though nothing had changed from Number 10’:

When I went to see her she’d say, ‘Will you have a coffee and sit down’. Then she looks at me expectantly, ‘What is the problem?’ So on the way in on the train, I always acquired a problem from reading the papers. And we discussed this problem at least six times in the hour, because she’d forgotten. It would have been funny if it weren’t tragic. Then she’d say, ‘Why have we got into this mess? But, more importantly, and what are we going to do about it?’

The search for meaning is deeply ingrained in human nature, so much so that, when pressed to define man, Plato replied simply, ‘a being in search of meaning.’

Memory is meaning, forgetting is death, and the job of the writer is not so much to teach as to remind.

But, of course, memory is not all that reliable. It could be argued that, like confabulation, nostalgia is a form of self-deception insofar as it involves distortion and idealization of the past. The Romans had a tag for the phenomenon that psychologists have come to call ‘rosy retrospection’: memoria præteritorum bonorum, ‘the past is always well remembered.’

And memory is unreliable in other ways as well. ‘Everyone’ said the writer John Barth, ‘is necessarily the hero of his own life story.’ We curate our memories by consolidating those that confirm or conform with our idea of self, while discarding or distorting those that conflict with it. We are most likely to remember events of existential significance such as our first kiss or first day at school—and, of course, it helps that we often rehearse those memories. Even then, we remember only one or two scenes, and only the main elements, and fill in the gaps and background with reconstructed or ‘averaged’ memories. Déjà-vu, the sense that an ongoing situation has already been experienced, may arise from a near match between the ongoing situation and an averaged memory of that sort of situation.

Our memories are filtered through and distorted by our interests and emotions. Two people supporting opposing football teams or political parties will register and recall very different things and likely disagree about ‘the facts’. In the UK in the aftermath of the 2019 European Elections, both ‘leavers’ and ‘remainers’ claimed to have won the ballot—but who can remember that now?

Broadly speaking, emotionally charged events are more likely to be remembered, and it has been found that injections of cortisol or adrenaline (epinephrine) can improve retention rates. But if a situation is highly stressful, memory may be impaired as cognitive resources are diverted to dealing with the situation, for example, escaping from the gunman rather than registering his clothing or facial features. In addition, any attention paid to the gunman is likely to focus on the gun itself, leading to a species of peripheral blindness. This, of course, has important implications for the accuracy of eyewitness testimony, which might be further distorted by the use of leading or loaded questions.

In a famous study, Reconstruction of Automobile Destruction [sic.], Loftus and Palmer asked people to estimate the speed of motor vehicles at their point of impact and found that the verb used in the question (‘smashed’, ‘collided’, ‘bumped’, ‘hit’, or ‘contacted’) altered perceptions of speed. In addition, those who had been asked the ‘smashed’ question were more likely to report having seen broken glass.

After a traumatic event, in response to unbearable stress, a person might go so far as to dissociate from the event, for example, by losing all memory for the event (dissociative amnesia) or even, as Agatha Christie famously did, assuming another identity and departing on a sudden, unexpected journey (dissociative fugue).

So heightened emotion improves memory, but severe stress and trauma impede it.

Of all the senses, it is the sense of smell that triggers the most vivid memories, even when these are from the very distant past.

The olfactory bulb has direct connections to the amygdala and hippocampus, which are heavily involved in memory and emotion. These three structures—the olfactory bulb, the amygdala, and the hippocampus—form part of the limbic system, a ring of phylogenetically primitive, ‘paleomammalian’ cortex that is the seat of memory, emotion, and motivation.

In a famous passage now referred to as ‘the madeleine moment’, Marcel Proust crystallized the uncanny ability of certain smells and tastes to evoke and in some sense recapture the ‘essence of the past’:

No sooner had the warm liquid mixed with the crumbs touched my palate than a shudder ran through me and I stopped, intent upon the extraordinary thing that was happening to me. An exquisite pleasure had invaded my senses, something isolated, detached, with no suggestion of its origin. And at once the vicissitudes of life had become indifferent to me, its disasters innocuous, its brevity illusory – this new sensation having had on me the effect which love has of filling me with a precious essence; or rather this essence was not in me it was me. ... Whence did it come? What did it mean? How could I seize and apprehend it? ... And suddenly the memory revealed itself. The taste was that of the little piece of madeleine which on Sunday mornings at Combray (because on those mornings I did not go out before mass), when I went to say good morning to her in her bedroom, my aunt Léonie used to give me, dipping it first in her own cup of tea or tisane. The sight of the little madeleine had recalled nothing to my mind before I tasted it. And all from my cup of tea.

Killing two birds with one stone, here are 10 ways to improve your memory that also shed light on its workings.

1. Get plenty of sleep. If you read a book or article when very tired, you will forget most of what you have read. Sleep improves attention and concentration, and therefore the registration of information. And sleep is also required for memory consolidation.
2. Pay attention. You cannot take in information unless you are paying attention, and you cannot memorize information unless you are taking it in. It helps if you are actually interested in the material, so try to develop an interest in everything! As Einstein said, ‘There are only two ways to live your life. One is as though nothing is a miracle. The other is as though everything is a miracle.’
3. Involve as many senses as you can. For instance, if you are sitting in a lecture, jot down a few notes. If you are reading a chapter or article, read it aloud to yourself and inject some drama into your performance.
4. Structure information. If you need to remember a list of ingredients, think of them under the subheadings of starter, main, and dessert, and visualize the number of ingredients under each subheading. If you need to remember a telephone number, think of it in terms of the first five digits, the middle three digits, and the last three digits—or whatever works best.
5. Process information. If possible, summarize the material in your own words. Or reorganize it so that it is easier to learn. With more complex material, try to understand its meaning and significance. Shakespearean actors find it much easier to remember their lines if they can understand and feel them. If needs must, concentrate on the important things, or the bigger picture. In the words of Oscar Wilde, ‘One should absorb the colour of life, but one should never remember its details. Details are always vulgar.’
6. Relate information to what you already know. New information is much easier to remember if it can be contextualized. A recent study looking at the role of high-level processes found that chess knowledge predicts chess memory (memory of the layout of a particular chess game) even after controlling for chess experience.
7. Use mnemonics. Tie information to visual images, sentences, and acronyms. For example, you might remember that your hairdresser is called Sharon by picturing a rose of Sharon or Sharon fruit. Or you might remember the colours of the rainbow and their order by the sentence, ‘Richard Of York Gave Battle In Vain.’ Many medics remember the symptoms of varicose veins by the acronym ‘AEIOU’: Aching, Eczema, Itching, Oedema, and Ulceration.
8. Rehearse. Sleep on the information and review it the following day. Then review it at increasing intervals until you feel comfortable with it. Memories fade if not rehearsed, or are overlain by other memories and can no longer be accessed.
9. Be aware of context. It is easier to retrieve a memory if you find yourself in a similar situation, or similar state of mind, to the one in which the memory was laid. People with low mood tend to recall their losses and failures while overlooking their strengths and achievements. If one day you pass the cheesemonger in the street, you may not, without her usual apron and array of cheeses, immediately recognize her, even though you are otherwise familiar with her. You might even say something like, ‘Gosh, remind me, where do I know you from?’ If you are preparing for an exam, try to recreate the conditions of the exam: for example, sit at a similar desk, at a similar time of day, and use ink on paper.
10. Be creative. Bizarre or unusual experiences, facts, and associations are easier to remember. Because unfamiliar experiences stick in the mind, trips and holidays give the impression of ‘living’, and, by extension, of having lived for longer.

Our life is just as long or short as our remembering: as rich as our imagining, as vibrant as our feeling, and as profound as our thinking.