Method of loci
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. For example, after relating the story of how Simonides relied on remembered seating arrangements to call to mind the faces of recently deceased guests, Stephen 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." 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. 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." 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". 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.
Procedural memory
The difference between procedural and declarative memory systems was first explored and understood with simple semantics.
Psychologists and philosophers began writing about memory over two centuries ago. "Mechanical memory" was first noted in 1804 by Maine de Biran. William James, within his famous book: "The Principles of Psychology" (1890), suggested that there was a difference between memory and habit. Cognitive psychology disregarded the influence of learning on memory systems in its early years, and this greatly limited the research conducted in procedural learning up until the 20th century. The turn of the century brought a clearer understanding of the functions and structures involved in procedural memory acquisition, storage and retrieval processes.