There is a long history of the use of mental images in the art of memory (Yates, 1966). One important technique is the ancient method of loci, in which mental imagery is used to remember a sequence of ideas (e.g. ideas to be presented in a speech). The memory portion of Ad Herrenium, an anonymous text that originated in Rome circa 86 BC and which reached Europe by the middle ages, teaches the method of loci as follows: a well known building is used as a ‘wax tablet’ onto which memories are to be ‘written’. As one mentally moves, in order, through the rooms of the building, one plac-es an image representing some idea or content in each locus that is, in each imagined room. During recall, one mentally walks through the building again, and ‘sees’ the image stored in each room. “The result will be that, reminded by the images, we can repeat orally what we have committed to the loci, proceeding in either direction from any locus we please” (Yates, 1966, p. 7).
In order for the method of loci to be effective, a great deal of effort must be used to initially create the loci to be used to store memories (Yates, 1966). Ancient rules of memory taught students the most effect way to do this. According to Ad Herrenium each fifth locus should be given a distinguishing mark. A locus should not be too similar to the others, to avoid confusion via resemblance. Each locus should be of moderate size (and should not be brightly lit), and the intervals between loci should also be moderate (about thirty feet). Yates (1966, p. 8) was struck by “the astonishing visual precision which [the classical rules of memory] imply. In a classically trained memory the space between the loci can be measured, the lighting of the loci is allowed for.”
- Yates, F. A. (1966). The Art Of Memory. Chicago, IL: University of Chicago Press.
(Added March 2011)