In this article the adjective “comparative” simply means that I want to establish a comparison between the history of memory and the psychological implications which it involves. Too many times the art of memory has been studied only from a historical and cultural point of view without considering the psychological and – above all – the strategic value of its findings.
A mythological birth
The art of memory was born inside the rhetorical tradition, but legend is that it has fantastical origins. As well known, Cicero retraces the story of the birth of the art of memory into the Intitutio oratiorae where he tells what happened to Simonides of Ceo when he was a guest at a banquet in the palace of Scopas, the Thassalian nobleman. Scopas refused to pay Simonides the full amount for the ode that he had sung. Scopas said to Simonides that he had to go to the mythical Twins to have half of the payment due, since he played the ode not only for his host but also for Castor and Pollux. In the sequel of the feast someone told Simonides that outside the palace two young men wanted to speak with him. Simonides went out to meet the young men, but nobody was there. In the meantime, the palace collapsed and all the people who were inside died. The young men, who called Simonides outside thus saving him, were the mythical Twins that had come to pay their part of the price for the ode. All the people at the feast were dead and completely unrecognizable so much had the stones of the walls and the ceiling mangled them. But Simonides remembered the position that they had at the table, so he was able to identify the bodies – by mentally retracing the occurring of the banquet and the order of the places where the victims were – in such a way that their relatives could bury them.
The fundamental principles of mnemonics
After this dreadful and shocking occurrence, Simonides grasped that a good order of mental images is fundamental for a good memory. The position where the guests sat at the table and the form, the image itself of the table, guaranteed a number of fixed places in memory. The association of the figure of the different guests with the various place at the table allowed Simonides a good mental sequence of the guests’ names, names that he mentioned in the right order.
The classical art of memory is quite easy to understand: it is based on the theory of loci (a Latin word that means “place”, “location”, “area”) and the story of Simonides is the first and most famous example of it. It is based on three principles: A) you have to put everything you want to memorize in a place ; B) you have to organize the places in a precise order; C) and finally you have to conceive the things and the places with bright pictures.
The theatre of memory
In the Renaissance the defined and established order of the places was called ‘theatre’. The concept of theatre of memory is structured in analogy with the classic Greek theatre; indeed in the Renaissance there were those who tried to build a real wooden theater. I refer to Giulio Camillo Delminio, an Italian philosopher and humanist that wrote a book (Idea del Theatro, Venice, 1550) in which he described a theater similar to the classical one but with the positions of the spectators and the actors overturned. In his idea the spectator (the mnemonist) is on the stage (proscenium) and he observes the actors (the images of the thing that he wants to memorize) on the stalls. It is unclear whether he actually was able to build a prototype of this kind of theater; what is important is the idea, since a real theatre of memory is not “real”, it is only envisaged. Thus, a theatre of memory could be every sequence of locations we can imagine. The path from house to work could be a theatre of memory and the door of the house, the bus stops, the newsstand, the coffee bar and the entrance to the office could be memory places. In each place we can put an image of the things we want to memorize.
The fundamental elements of the art of memory
From what we have just said, we can derive that the fundamental elements of the art of memory are: THING (the image of everything you want to memorize: a concept, an idea, an episode, a physical object, a subject of study, a perception or whatever you want), PLACE (the mental representation of a physical or imagined or fancy place fixed in mind once and for all in which to put the depiction of the things to memorize. Depending on the type of chosen method, we can also call the place with the name of “stage” or “stop”) and the THEATRE (the exact – and always the same – sequence of the places). We can fill and empty the places of the theatre every time we want to or we need to. We can change the things in the places, but not the sequence of the places in the theatre. If we modify the sequence we transform the theatre into another different theatre. So the sequence of the places must be always the same, but the things in the places can be substituted every time. The places are stables and constants and the things in them are variables and/or replaceable.
The method of loci
Almost without naming it, we have already partly described the method of loci. How exactly does it work? A building, a room, the route from home to the workplace, a train journey, etc. all of these and much more things can become a theatre of memory. However, there are two conditions to be met: 1) the path and the places must be well known; 2) the path must have no interruptions, this means that if I think of an apartment as a theatre I cannot skip a room in the succession of the mental places. If my theatre is a train journey, each station is a place of memory, I cannot skip any station, unless to spoil the sequence of places (stations), namely the shape of the theatre. There is a third rule, but it is not mandatory: it is better if you use circular paths or, at least, paths in which the last stage (place) is in sequence with the first one. Take for example an office as shown in “Figure 2”. We must take as landmarks ten objects present in the room. As mentioned previously, we must think about these places in their exact sequence as they are reproduced in “Figure 2”: 1) the door; 2) the card index cabinet; 3) the desk of the office worker; 4) the east window; 5) the desk of the head office; 6) the cupboard; 7) the couch; 8) the west window; 9) the conference table; 10) the wardrobe. We must think about the spaces around these objects and these spaces become our places of memory. In these places we have to put the images of the thing we have to store. If we have to memorize a list of ten names (names like this: 1. a cat; 2. an airplane; 3. a book; 4. a pair of boots; 5. a knife; 6. a comb; 7. a bunch of keys; 8. a car; 9. a spoon; 10) a backpack) we have to link or, better, put (through imagination) each object in each place in the right order.
1) the door → a cat
2) the card index cabinet → an airplane
3) the desk of the office worker → a book
4) the east window → a pair of boots
5) the desk of the head office → a knife
6) the cupboard → a comb
7) the couch → a bunch of keys
8) the west window → a car
9) the conference table → a spoon
10) the wardrobe → a backpack
When we retrace the mental path that thus we have stored, we will also naturally recover the things that we had placed in its spaces. If we have thoroughly memorized the sequence of places, and if we strongly imagined the things in them, we can retrieve the latter without much effort .
The dimension of the images and that of the places
We have to pretend that these objects are really in these places, even if this happens only in our mind. We have to pretend to see that these objects are effectively there. One of the first things you have to ask is «How can I get an airplane upon a card index cabinet?». Of course, in reality an airplane is very big, but in your imagination it is the size that you decide that it is. You have to parameterize the dimension of the object to the dimension of the place. In this case you have to reduce the dimension of the airplane till it can stay on a card index cabinet; or you can think straight to a scale model of the airplane. In another situation you can imagine enlarging or reducing the size of objects at your leisure. Each image in your imagination and in your memory has the size and shape that you decide that it has.
How can we decide which images to use?
Another question that comes naturally to ask at this point is: «How can we decide which images to use?» Usually, the first images that come to mind are the most appropriate. It is difficult to establish a strict rule since each person has an imagination unlike any other person, but usually the first image that comes to mind when we think, or listen, to an object is the right one. We must only take care that the image is quite definite in our minds. It should be not too much nor too little defined, but it must be represented with the right number of details in such a way that the image thus produced can help memory. If it has too many details it becomes a burden for the memory; if it has too few of them it fades quickly in our minds. You learn the right fit with exercise, but learning is much simpler than it seems. Also if we don’t pay a lot of attention to it, our imagination is used to produce representations useful to remember things and thoughts at the time when we think of them. We should just try and exercise and do intentionally what our mind often does spontaneously.
How many loci must a theatre have?
In order that the “loci” method becomes effective, we have to memorize very well the places and their sequence and after we have to exercise ourselves to create vivid and appropriate images. Thus this strategy can become the most effective mnemonic system ever. A theatre of memory may have any number of places. You decide how large or long it need to be. Almost always it depends on what place you decide to be a theatre of memory: a building, or a track (path), or anything else. If your inspiration is a real place, you have to get to grips with its form and its size. To the contrary if you imagine a fictitious theatre, you can shape it as you prefer. Usually I suggest making two different theatres. The first one should consist of a hundred places; the second one should be composed of only thirty places. These numbers are not chosen randomly: having theatres composed like these will be useful when we have to deal with some advanced mnemonic techniques. At the beginning, if you think you might have problems building such big theatres, you could try with slightly smaller theatres, but I’m sure that with a little exercise you can use a hundred places without problems.
How to empty the places of memory
It remains to answer another common question: «How can I use the same places if I’ve already filled them with things?» or, in other words, «If in a place there is already an old thing, how can I replace it with another new thing without causing confusion?» Generally, if we have memorized the places well, we find them empty in our mind after using them, of course, unless we decide voluntarily to keep something in memory. Anyway, a different solution could be found to think that the places are empty. Think about a blank space in our places is the easiest way to erase old memories. Something similar, but slightly more complex, was done by the famous mnemonist Sereševskij: «You may envy Sereševskij’s memory powers. However, he found it extremely difficult to forget anything and so his memory was cluttered up with all sorts of information he didn’t want to recall. Eventually, he hit on a very simple solution – he imagined the information he wished to remember written on a blackboard and then imagined himself rubbing it out. Strange to relate, this worked perfectly!» . We must remember that Sereševskij was a clinical subject, studied by the neuropsychologist Alexander Luria. On the contrary, what happens to the majority of people is to find the places free, empty when they want to put in something, and full when they want to gather the memories that they lay in.
 Clearly: “put the things in a place” doesn’t mean in a physical one but only imagining a real or an imaginary place and putting into it the things to remember. We have to do this only with the imagination.
 «It is not difficult to get hold of the general principles of the mnemonic. The first step was to imprint on the memory a series of loci or places. The commonest, though not the only, type of mnemonic place system used was the architectural type. The clearest description of the process is that given by Quintilian. In order to form a series of places in memory, he says, a building is to be remembered, as spacious and varied a one as possible, the forecourt, the living room, bedrooms, and parlours, not omitting statues and other ornaments with which the rooms are decorated. The images by which the speech is to be remembered – as an example of these Quintilian says one may use an anchor or a weapon – are then placed in imagination on the places which have been memorized in the building. This done, as soon as the memory of the facts requires to be revived, all these places are visited in turn and the various deposits demanded of their custodians. We have to think of the ancient orator as moving in imagination through his memory building whilst he is making his speech, drawing from the memorized places the images he has placed on them. The method ensures that the points are remembered in the right order, since the order is fixed by the sequence of places in the building.» F.A. Yates, The art of memory, Routledge & Kogan Paul, London - New York, 1966 p.3.
 Baddeley, M.W. Eysenek, M. Anderson, Memory, New York, Psychology press, 2015, p. 479.
Continues on the 29th of August.