Memory improvement techniques are called mnemonic devices or simply mnemonics. Mnemonics have been used since the time of the ancient Greeks and Romans. In ancient times, before writing was easily accomplished, educated people were trained in the art of memorizing. For example, orators had to remember points they wished to make in long speeches. Many of the techniques developed thousands of years ago are still used today. Modern research has allowed psychologists to better understand and refine the techniques.
All mnemonic devices depend upon two basic principles discussed earlier in this article: (1) recoding of information into forms that are easy to remember, and (2) supplying oneself with excellent retrieval cues to recall the information when it is needed. For example, many schoolchildren learn the colors of the visible spectrum by learning the imaginary name ROY G. BIV, which stands for red, orange, yellow, green, blue, indigo, violet. Similarly, to remember the names of the Great Lakes, remember HOMES (Huron, Ontario, Michigan, Erie, and Superior). Both of these examples illustrate the principle of recoding. Several bits of information are repackaged into an acronym that is easier to remember. The letters of the acronym serve as retrieval cues that enable recall of the desired information.
Psychologists and others have devised much more elaborate recoding and decoding schemes. Three of the most common mnemonic techniques are the method of loci, the pegword method, and the PQ4R method. Research has shown that mnemonic devices such as these permit greater recall than do strategies that people usually use, such as ordinary rehearsal (repeating information to oneself).