A mnemonist is very good at which ability?

The title mnemonist, derived from the term mnemonic, refers to an individual with the ability to remember and recall unusually long lists of data, such as unfamiliar names, lists of numbers, entries in books, etc. The duration of superior retention can be minutes, hours, days, or decades. Mnemonists may have superior innate ability to recall or remember, or may use techniques such as the method of loci.

While the innateness of mnemonists' skills is debated, the methods that mnemonists use to memorize are well-documented. Many mnemonists have been studied in psychology labs over the last century, and most have been found to use mnemonic devices. Currently, all memory champions at the World Memory Championships have said that they use mnemonic strategies, such as the method of loci, to perform their memory feats.

Skilled memory theory was proposed by K. Anders Ericsson and Bill Chase to explain the effectiveness of mnemonic devices in memory expertise. Generally, short-term memory has a capacity of seven items; however, in order to memorize long strings of unrelated information, this constraint must be overcome. Skilled memory theory involves three steps: meaningful encoding, retrieval structure, and speed-up.