The method of loci (plural of Latin locus for place or location), also called the memory palace, is a mnemonic device introduced in ancient Roman rhetorical treatises (in the anonymous Rhetorica ad Herennium, Cicero's De Oratore, and Quintilian's Institutio oratoria). It relies on memorized spatial relationships to establish, order and recollect memorial content. The term is most often found in specialised works on psychology, neurobiology and memory, though it was used in the same general way at least as early as the first half of the nineteenth century in works on rhetoric, logic and philosophy.[1]
The method of loci is also commonly called the mental walk. In basic terms, it is a method of memory enhancement which uses visualization to organize and recall information. Many memory contest champions claim to use this technique in order to recall faces, digits, and lists of words. These champions’ successes have little to do with brain structure or intelligence, but more to do with their technique of using regions of their brain that have to do with spatial learning. Those parts of the brain that contribute most significantly to this technique include the medial parietal cortex, retrosplenial cortex, and the right posterior hippocampus.
O'Keefe and Nadel refer to
'the method of loci', an imaginal technique known to the ancient Greeks and Romans and described by Yates (1966) in her book The Art of Memory as well as by Luria (1969). In this technique the subject memorizes the layout of some building, or the arrangement of shops on a street, or any geographical entity which is composed of a number of discrete loci. When desiring to remember a set of items the subject literally 'walks' through these loci and commits an item to each one by forming an image between the item and any distinguishing feature of that locus. Retrieval of items is achieved by 'walking' through the loci, allowing the latter to activate the desired items. The efficacy of this technique has been well established (Ross and Lawrence 1968, Crovitz 1969, 1971, Briggs, Hawkins and Crovitz 1970, Lea 1975), as is the minimal interference seen with its use.[2]
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The designation is not used with strict consistency. In some cases it refers broadly to what is otherwise known as the art of memory, the origins of which are related, according to tradition, in the story of Simonides of Ceos and the collapsing banquet hall.[3] For example, after relating the story of how Simonides relied on remembered seating arrangements to call to mind the faces of recently deceased guests, Steven M. Kosslyn remarks "[t]his insight led to the development of a technique the Greeks called the method of loci, which is a systematic way of improving one's memory by using imagery."[4] Skoyles and Sagan indicate that "an ancient technique of memorization called Method of Loci, by which memories are referenced directly onto spatial maps" originated with the story of Simonides.[5] Referring to mnemonic methods, Verlee Williams mentions, "One such strategy is the 'loci' method, which was developed by Simonides, a Greek poet of the fifth and sixth centuries BC"[6] Loftus cites the foundation story of Simonides (more or less taken from Frances Yates) and describes some of the most basic aspects of the use of space in the art of memory. She states, "This particular mnemonic technique has come to be called the "method of loci".[7] While place or position certainly figured prominently in ancient mnemonic techniques, no designation equivalent to "method of loci" was used exclusively to refer to mnemonic schemes relying upon space for organization.[8]
In other cases the designation is generally consistent, but more specific: "The Method of Loci is a Mnemonic Device involving the creation of a Visual Map of one's house."[9]
This term can be misleading: the ancient principles and techniques of the art of memory, hastily glossed in some of the works cited above, depended equally upon images and places. The designator "method of loci" does not convey the equal weight placed on both elements. Training in the art or arts of memory as a whole, as attested in classical antiquity, was far more inclusive and comprehensive in the treatment of this subject.
In a classic study in cognitive neuroscience O'Keefe and Nadel proposed "that the hippocampus is the core of a neural memory system providing an objective spatial framework within which the items and events of an organism's experience are located and interrelated."[10] This theory has generated considerable debate and further experiment. It has been noted that "[t]he hippocampus underpins our ability to navigate, to form and recollect memories, and to imagine future experiences. How activity across millions of hippocampal neurons supports these functions is a fundamental question in neuroscience, wherein the size, sparseness, and organization of the hippocampal neural code are debated."[11]
"Using neuropsychological, structural, and functional brain imaging measures, we found that superior memory is not driven by exceptional intellectual ability or structural brain differences. Rather, we found that superior memorizers used a spatial learning strategy (the method of loci; Yates, 1966) while preferentially engaging brain regions critical for memory and for spatial memory in particular, including the hippocampus."[12]
The "method of loci," as first described by Simonides (cf. Yates, 1966), is explicitly spatial. In this technique, subjects improve memory by putting to-be-remembered items into some place or spatial context. Retrieval is effected simply by "going" to that place in thought [...] Events occurring within separate contexts are efficiently recalled in those contexts and minimally confused between contexts, though the events themselves might be highly similar. The mental maps we have of our home town, our neighborhood, and our house are all examples of the kinds of spatial contexts within which events occur, can be coded internally, and can subsequently be effectively retrieved or recalled: Studies by Smith, Glenberg, and Bjork (1978) and Bellezza and Reddy (1978) indicate that the power of the method of loci might lie in its ability to take advantage of this natural state of affairs.[13]
The medial parietal cortex is most associated with encoding and retrieving of information. Patients who suffered from medial parietal cortex damage had troubles linking landmarks with certain locations. Many of these patients were unable to give or follow directions and often got lost.
The retrosplenial cortex is also greatly linked to memory and navigation. In Pothuzien HH’s study on the effects of selective granular retrosplenial cortex lesions in rats, the researcher found that damage to the retrosplenial cortex lead to impaired spatial learning abilities. Rats with damage to this area failed to recall which areas of the maze they had already visited, rarely explored different arms of the maze, almost never recalled the maze in future trials, and took longer to reach the end of the maze, as compared to rats with a fully working retrosplenial cortex.
The mental walk originated from the idea that you can best remember things that you are familiar with. Therefore, by associating a certain object with a familiar landmark, you increase your chances of remembering that object. Since the mental walk revolves around the idea of visualizing a familiar place and associating certain ideas or items with landmarks within that familiar place, the medial parietal cortex plays a huge role in this technique. Without the ability to mentally “walk” through a familiar route, this method cannot work.
All top memorisers today use the 'method of loci' to a greater or lesser degree. Contemporary memory competition was initiated in 1991 [14] and introduced to the USA in 1997. Part of the competition requires committing to memory and recalling a sequence of digits, two-digit numbers, alphabetic letters, or playing cards. In a simple method of doing this, contestants, using various strategies well before competing, commit to long-term memory a unique vivid image associated with each item. They have also committed to long-term memory a familiar route with firmly established stop-points or loci. Then in the competition they need only deposit the image that they have associated with each item at the loci. To recall, they retrace the route, "stop" at each locus, and "observe" the image. They then translate this back to the associated item. Memory champions elaborate on this by combining images. Eight-time World Memory Champion Dominic O'Brien[15] advocates this technique. His name for it is The Journey Method. The 2006 World Memory Champion, Clemens Mayer from Germany, used a 300-point-long journey through his house for his world record in "number half marathon", memorising 1040 random digits in a half hour. One individual has used the method of loci to memorise pi to 65,536 digits.[16]
Using this technique a person with ordinary memorization capabilities, after establishing the route stop-points and committing the associated images to long-term memory, with less than an hour of practice, can remember the sequence of a shuffled deck of cards. The world record for this is held by Simon Reinhard at 21.90 seconds[17]
The technique is taught as a metacognitive technique in learning to learn courses. It is generally applied to encoding the key ideas of a subject. Two approaches are:
It has been found that teaching such techniques as pure memorization methods often leads students towards surface learning only. Therefore, it has been recommended that the method of loci should be integrated thoroughly with deeper learning approaches.
A recent variation of the "method of loci" involves creating imaginary locations (houses, palaces, roads and cities) to which the same procedure is applied. It is accepted that there is a greater cost involved in the initial setup, but thereafter the performance is in line with the standard loci method. The purported advantage is to create towns and cities that each represent a topic or an area of study, thus offering an efficient filing of the information and an easy path for the regular review necessary for long term memory storage.[18]
Something that is likely a reference to the "method of loci" techniques survives to this day in the common English phrases "in the first place", "in the second place", and so forth.[19]
In popular culture, the technique is employed by the fictional serial killer Dr. Hannibal Lecter in Hannibal (1999) the third of a series of novels by American author Thomas Harris. In several passages in the book, Dr. Lecter is described as mentally walking through an elaborate memory palace to remember facts.[20]
During the mental walk, people remember lists of words by mentally walking a familiar route and associating these objects with specific landmarks on their route. An example of this would be to remember your grocery shopping list in a mental walk from your bedroom to kitchen in your house. Let's say the first item on your list was bread; then mentally you can place a loaf of bread on your bed. As you continue mentally walking you can place the next item, assume it is eggs, on your dresser. The mental walk continues like this as you place consecutive items along a familiar route that you walk. So when you are at the grocery store, you can then think about this walk and “see” what you placed at each location. In your head you will remember bread being on your bed, and eggs being on the dresser. This can continue for as many items as you want to place on your path as long as the route continues. The more dramatic the images, the more vivid the memory. For instance: instead of "bread", try to visualize a giant loaf of bread; instead of "eggs", imagine broken eggs all over the place.