Most students, particularly those devoting their attentions to the sciences, will have placed considerable reliance on memorising data that would assist in examinations. Once a mnemonic has been adopted to assist the memory it is remembered long after it might prove useful academically. For example, that celebrated nonsense which establishes the order in which the cranial nerves of the central nervous system arise — "On Old Olympus' Topmost Top", etc — has a habit of sticking more firmly in the mind of anyone who has had any connection with human anatomy and physiology than other facts which perhaps might be more useful in the long run.
Memory was known to the Greeks as mneme, and was derived from the name of the goddess Mnemosyne, who bore to Zeus the nine muses Calliope, Clio, Euterpe, Thalia, Melpomene, Terpsichore, Erato, Polyhymnia and Urania, all of them at one time considered goddesses of memory, but later specialising in their patronage of various artistic endeavours. The Romans were more prosaic and long-winded, and referred to memory as ars discipline memoriae.
We still talk about mnemonics and, in the Lancet for November 4, Christian Manuel of Paris discusses some of the originators of mnemonic systems. In the first century AD the Roman philosopher Quintilian devised a system in which he attached ideas successively to rooms and ornaments in the house by visualising these locations. The idea has been promoted in modern times by mind-training exponents who advocate memorising numbers by attaching them to doors, corners, walls, floors and ceilings in a room in the home.
Manuel draws attention to the work of the Jesuit missionary to China, Father Matteo Ricci, who at the end of the 16th century taught Chinese students a method of improving their memory, called "palaces of memory" in which he asked them to imagine entering doors and climbing staircases with which items to be remembered should be identified. Ricci's own teacher, Francesco Panigarola, writes Manuel, managed to manipulate some 100,000 images. ‘‘If you have to memorise a great quantity of images, then build up hundreds or thousands of buildings. If you need only a few of them, just build up a hall and divide it in four quarters . . . ."
The question arises, why restrict oneself to visual stimuli while auditory, olfactory and tactile ones are equally available for devising a mnemonic system? Indeed, some musicians have used musical tones to enable them to establish trains of thought. There seem to be a case for having recourse to whatever type of stimulus an individual fancies to construct an efficient memorising technique. Most people keep their personal recall procedures to themselves, since they tend to be difficult if not impossible to demonstrate to others.