The Forgetting Machine

by Rodrigo Quian Quiroga

  Chapter 5

  CAN WE REMEMBER MORE?

  In which we describe the method of loci, the importance of memory in antiquity and today, the rebirth of the art of memory after the Middle Ages, the case of the man who could not forget, and savants

  Legend has it that the ancient Greek poet Simonides was called to the door to receive a message during a banquet, and just at that moment, the roof of the room he had just left collapsed, crushing all the other guests.1 When the rubble was cleared, the bodies found were too disfigured to be recognizable. However, Simonides was eventually able to identify the bodies by remembering where each guest had been seated. From this experience, Simonides inferred that sorting memories was the key to preserving them, and he went on to invent mnemonics, the art of harnessing various techniques to enhance memory. In particular, Simonides developed what is known as the method of loci (loci is Latin for “places”), which consists of associating objects with specific locations. To practice the method, we must visualize in detail a very familiar place, such as the street on which we live, and then distribute the items we wish to remember at specific points of this place in our minds. For example, if I want to remember a list of words—bread, chair, rock, car, book, glass, spoon, lamp, flower, sword, etc.—I can mentally distribute these objects along my street: there will be a large loaf of bread on the corner, and a chair in front of the door of the day-care center by that same corner; I shall place an enormous rock by the bus stop, and a yellow Ferrari just beyond the stop; at my neighbor’s door I’ll leave a huge book on a stand; in front of my house there will be a large glass full of effervescent liquid; my other next-door neighbor will have a giant spoon at her door, and the crosswalk will get a vast standing lamp that goes on and off whenever someone crosses the street. Further along, at the entrance to the school, there will be a mammoth flower greeting students, and I will put a monument to a sword in the middle of the park.

  Now, to remember the list of words, all I have to do is take an imaginary stroll down my street and note the objects I placed along it as I pass them by. I chose my street, but the chosen place could also have been the stretch from my front door to the garden (walking through the entrance hall, the living room door, the dining table, the couch, the television, the garden door, etc.), the route I take to go to work, or any other spatial arrangement that is both very familiar to me and that, ideally, has many reference points at which to place the objects that I want to remember. The power of this association is such that, even though I chose the words at random, I feel that they have been fixed in my memory at the places where I left them. In a few weeks, a few months, or even a few years, I will be able to remember most, if not all, of them.2 It is easy to corroborate the soundness of the method of loci by using, say, the same list of words as above (bread, chair, rock, etc.) and taking a few minutes to compare one’s ability to remember them by employing Simonides’s method, with the ability to recall a similar list of words (for example, painting, socket, television, clock, grass, ball, suitcase, kettle, boat, milk) by repeating those words until they stick in your mind. We may be able to remember both lists after a few minutes, but after a few hours we will certainly remember the first much better than the second.3

  For the method of loci to work, it is essential to choose eye-catching visual images to represent the objects we wish to remember. It is no coincidence that in the example above I highlighted the size and prominence of the images I used: a yellow Ferrari, a lamp that toggles on and off whenever someone crosses the street, a flower that greets schoolchildren, a monument to a sword, and so on. An enormous rock at the bus stop is, in fact, much easier to remember than a rolling pebble; a giant spoon resting against my neighbor’s door is easier to see and remember than a teaspoon lying on the sidewalk. The same method can be extended to other kinds of words. If I want to remember the name of a person, I can imagine this person at the bus stop smoking a cigarette, or juggling balls, or declaiming a poem with a megaphone. Any of these images will be more striking and memorable than one of the person simply standing at the bus stop doing nothing. Creating mental images also works to remember more abstract words. For example, if I want to remember the word “love,” I can imagine a couple kissing in a passionate embrace; if I want to remember the word “justice,” I can envision a judge in a black robe holding court, and so on. In the same way, we can remember lists of numbers by associating each number with an image.4

  Obviously, as we practice, if we wish to remember more items, we will need more reference points. For example, in the path through my house to the garden, I can define other locations: the fireplace, the kitchen door, the stereo; I can place up to six different objects on the dining table, one by each seat; I can put three objects on the couch, one on each cushion. The important bit here is to maintain the spatial order so that, as I imagine going from the front door to the back gate, the sequence of reference points is always the same.

  The method of loci illustrates several interesting aspects of how memory works. First, as Simonides observed, it is important to organize the items we are trying to remember, in order to avoid interference—that is, having some memories blocking others. For example, after an unstructured learning of the previous list of words, I may have problems recalling spoon because bread, car, and chair come to my mind, whereas the access to this item is much more effective when I can recall that spoon (and not bread, car, or chair) is the item by my neighbor’s door. Second, it places emphasis on vision. According to Cicero (De oratore II, LXXXVII, 357), Simonides understood that sight was the most important of the senses. In fact, we now know that a significant chunk of our brain is devoted to visual processing. Images use the machinery of our brain to its fullest extent and are far more memorable than numbers, letters, or words. Third, the method of loci highlights the importance of associations, in this case, of places with people or objects. In general, when we go back to a place, we remember not only the place itself but also whatever we did there. Fourth, the method of loci avails itself of the fact that the most memorable events are those that best capture our attention, using remarkable images that are ideally charged with emotional content. I can more easily remember my mother standing on a corner than I can remember an unfamiliar woman standing there.

  What practical relevance, if any, does the method of loci have today? After all, I can simply jot my grocery list on a slip of paper, I need only press a button to dial numbers stored in the memory of my phone, and with GPS there’s no need to remember the way to a friend’s house. In contrast, exercising and honing memory was crucial in antiquity, when there were no computers, cell phones, GPS devices, or even paper.5 If I have to give a one-hour talk at a conference, I can prepare a set of slides (in PowerPoint or Keynote for Mac) to aid my memory as I deliver the presentation. I do not have to memorize the talk in detail because I can be reminded of what I want to say as I am prompted by the slides. Back in my college days, these tools were not available, but professors lectured using notes they had prepared on paper (though a few did lecture from memory after having taught the same course over and over).

  Now imagine the case of a Roman senator who has to argue, for example, in favor of a tax increase. He may want to argue that, given the threat from Carthage, it is essential to build new warships; he cannot neglect to mention that it is critical to maintain a strong militia to combat the Persian empire; that it is necessary to fund the construction of a new temple and repair the aqueducts; etc. Each of these facts is vital, and the senator does not want to forget any, but since he has no paper to record them, he must resort to his memory. Thus the importance of mnemonics in antiquity—especially for public speaking. In fact, it is no coincidence that two of the era’s seminal treatises on memory were Cicero’s De oratore, and Institutio oratoria by Quintilian.6 The latter author has this to say on the subject:

  We would have never known how great and divine the power of memory is, were it not for the fact that it is memory that has brought rhetoric to its pr
esent glory. It provides the orator not just with a way to remember his thoughts, but even his words.

  —QUINTILIAN, INSTITUTIO

  ORATORIA, XI, II, 7–8

  In one of Plato’s dialogues, Critias argues (before giving a speech and after having been advised to invoke various deities) that:

  besides the gods and goddesses whom you have mentioned, I would specially invoke Mnemosyne [the ancient Greek goddess of memory]; for all the important part of my discourse is dependent on her favour, and if I can recollect and recite enough … I doubt not that I shall satisfy the requirements of this theatre.

  —PLATO, CRITIAS (TRANSLATED

  BY BENJAMIN JOWETT)

  In antiquity, a good memory was seen as a great virtue, and there are many accounts of persons with extraordinary powers of recall. For example, it was said that Seneca, the Roman philosopher who was an advisor to Nero, could repeat two thousand names in the same order they were given to him; Charmadas, of Greece, could recite by heart a book as though he were reading from it; Mithridates, king of twenty-two nations, could administer justice in every language spoken in his empire; Cyrus, king of Persia, knew the names of all his soldiers, while Lucius Scipio knew the names of all in Rome, and Cineas, King Pyrrhus’s ambassador, learned the names of all the Roman senators just one day after arriving in the city.7 This list must also include Metrodorus of Scepsis, who perfected the method of loci by distributing the items to be remembered over 360 partitions of the zodiac and who, according to Cicero, could etch in his memory everything he wanted to remember “as though he were engraving letters on wax.”8

  The practice of oratory, and thus of mnemonics, was lost during the Middle Ages but was taken up again during the Renaissance, starting in the late fifteenth century.9 This rebirth of the art of memory can be attributed to several people, among them Peter of Ravenna, an Italian jurist who in 1491, a year before Columbus’s discovery of the New World, published Phoenix seu artificiosa memoria, a treatise on memory that was widely disseminated in his day. Peter of Ravenna wrote that his practice of memory enabled him to learn and recite, among other things, “the whole of the canon law, text and gloss . . . ; two hundred speeches or sayings of Cicero; three hundred sayings of the philosophers; twenty thousand legal points.”10 Curiously, regarding the application of the method of loci, Peter of Ravenna suggested using calm places as the locations in which to sort items to remember, for instance, placing a series of reference points within a familiar and sparsely visited church, though he also, apologizing in passing to chaste and religious men, suggested using striking images, such as those of comely virgins.

  Later, in the early sixteenth century, Giulio Camillo envisioned classifying and sorting information via an imagined grand theater with seven levels and seven sections, where each division was represented by a particular image and was associated with data and writings on different areas of knowledge. The images in each section and level would bring about, according to Camillo, the ordered remembrance of the knowledge associated with them, in such a way that “whoever is admitted as a spectator will be able to discourse on any subject no less fluently than Cicero.”11 In particular, referring to the monumental task of distributing all the knowledge of his time among the different divisions of his theater, Camillo argued that, “if the ancient orators, wishing to place from day to day the parts of the speech which they had to recite, confided them to frail places [the different reference points used in the method of loci] as frail things it is right that we, wishing to store up eternally the eternal nature of all things which can be expressed in speech . . . should assign to them eternal places.”12 Shortly thereafter, Giordano Bruno, the philosopher, cosmologist, and Dominican friar, built an elaborate mnemonic wheel consisting of rotating concentric circles with 150 divisions, each with different images and symbols to represent categories and items to be remembered. Given his revolutionary ideas, like his support of Nicolaus Copernicus’s notion of heliocentrism (while allowing for an infinite, unlimited space where intelligent life might be found on other planets, and regarding the sun as just one of a multitude of stars), his pantheistic vision of the human being as conscious matter reflecting the cosmic soul of the universe, and his use of pagan images and magical practices in his work on developing the art of memory, it is perhaps not unexpected to hear Giordano Bruno is sadly remembered as a martyr of science, executed by the Inquisition.13

  Figure 5.1: Mnemonic methods of Camillo and Bruno

  Reconstruction of Camillo’s theater (top) and of Giordano Bruno’s memory wheel (bottom left) as presented by historian Frances Yates, and a statue of Giordano Bruno in the Campo de’ Fiori, in Rome, where he was put to death by the Inquisition (bottom right)

  The flourishing, during the Renaissance, of literature on the art of memory left its traces in the writings of thinkers from Francis Bacon to Descartes and Leibniz.14 However, I would like to end this brief historical digest by chronicling a relatively more recent aficionado of the art, namely Solomon Shereshevskii, one of the most outstanding mnemonic practitioners ever to have lived.

  In the 1920s, Solomon Shereshevskii worked as a journalist for a Moscow newspaper. One day he visited a young Alexander Luria—who would go on to become one of Russia’s most noted psychologists—and confessed to a problem: strange as it may sound, he could not forget. When a skeptical Luria decided to test Shereshevskii’s memory, he found that Shereshevskii could remember with no effort lists of thirty, fifty, and even seventy numbers. And not just that: he could repeat the list in forward or reverse order starting at any point. Shereshevskii simply continued to see the sequences in his memory, whether they were numbers, words, sounds, or meaningless syllables, after simply reading them. Such was Luria’s fascination with Shereshevskii that he studied the man for three decades and verified that Shereshevskii could keep these sequences in his memory for years after learning them, without expecting that he would ever be asked about them again.15

  Shereshevskii’s astonishing memory was due to his use of the method of loci and, above all, to a very strong synesthesia. People with synesthesia may mix perceptions from different senses, for example by associating numbers with colors—“seeing” 3 as purple, 4 as yellow, etc. In Shereshevskii’s case, however, these associations went much further: every letter, number, or word set off an avalanche of visual imagery, sounds, tastes, and tactile sensations. As Luria reports, Shereshevskii could recognize and remember words not just by the images they evoked, but by the whole complex of associations that those images aroused. Numbers, for Shereshevskii, corresponded to specific images: 1 was a proud, well-built man; 2 a high-spirited woman; 3 a gloomy person; 6 a man with a swollen foot; 7 a man with a mustache; 8 a very stout woman—“a sack within a sack”—etc.

  Figure 5.2

  Images of Alexander Luria (left) and Solomon Shereshevskii (right)

  Given his synesthesia, using the method of loci came naturally to Shereshevskii; the images were already fixed in his brain in extraordinarily rich detail. To remember a list of objects, Shereshevskii distributed them along a street of his hometown or a well-known avenue in Moscow and, once he did this, he could take a mental stroll and simply recite out loud what he saw—like the orators of antiquity, but with a remarkable degree of precision. I will refrain from dwelling longer on Shereshevskii’s incredible memory capacity, which has already been brilliantly described by Luria in his book. However, I would like to discuss, as Luria did, one very intriguing aspect of Shereshevskii’s case: What were the consequences of having such a memory?

  Shereshevskii eventually began a career as a professional mnemonist. For several performances a night, he would memorize sequences written out for him on a blackboard by members of the audience, and these sequences began to torment him as they amassed in his memory with no apparent limit. Shereshevskii’s torment inevitably brings to mind that of Ireneo Funes, the fictional protagonist of the Borges short story discussed in the previous chapter as we stressed the importance of for
getting.16 After falling off a horse and hitting his head, Funes became able to remember absolutely everything. Yet this ability, which would have seemed a godsend to an ancient Roman orator and was described by Pliny as almost heroic, the “greatest gift of Nature” that could be had by a person, was for Funes not just a handicap, but a curse. In fact, Borges concluded that Funes “was not very capable of thinking. To think is to forget differences, to generalize, to abstract.”17

  Just as Funes’s memories wound up being “a rubbish heap,” Luria describes the difficulties Shereshevskii experienced due to his huge memory, and the paradoxical efforts he made to forget. Shereshevskii’s memory worked exclusively through visual imagery and employed no internal logic. For example, when he was asked to memorize a list of words that included—among other things—several bird species and later another list that included the names of several liquids, Shereshevskii could repeat both lists without effort . . . but was unable to name only the birds in the first sequence or the liquids in the second. Another time, Luria gave Shereshevskii a sequence that he remembered perfectly through the power of his visual memory . . . but without noticing that it was composed of consecutive numbers.

  Shereshevskii’s lack of ability to reason or think abstractly meant he was incapable of understanding the content of what he read. Though he could recite long passages by rote and remember them for many years, he was unable to abstract the content of a book enough to apprehend its meaning. In other words, while ordinary people remember only a few facts, abstracting and inferring narrative so they can continue to follow a story as it develops, Shereshevskii had to fight against an overwhelming and uncontrollable tide of memories and associations, sparked by each and every word, that impeded his attempts to grasp the meaning of what he was reading. Moreover, Shereshevskii was sometimes unable to avoid noting and remembering small variations in the tone of voice of the person speaking to him and thus could not follow what he was being told. Even more striking is the fact that Shereshevskii found it difficult to remember faces, because, as he said, “people’s faces are constantly changing [and] the different shades of expression . . . confuse me.”