Generally cognitive psychologists divide memory into three stores: sensory store, short-term store, and long-term store. After entering the sensory store, some information proceeds into the short-term store. This short-term store is commonly refered to as short-term memory.
Short-term memory has two important characteristics. First, short-term memory can contain at any one time seven, plus or minus two, "chunks" of informaton. Second, items remain in short-term memory around twenty seconds. These unique characteristics, among others, suggested to researchers that short-term memory was autonomous from sensory and long-term memory stores
Craik and Lockhart (1972) argued short-term memory was not autonomous from the other memory systems. They suggested that short-term memory and long-term memory were different manifestations of a single, underlying memory system.
As an alternative to short-term memory Baddely and Hitch have propsed the concept of a working memory. As in traditional models of short-term memory, working memory is limited in the amount of information that it can store, and the length of time that it can store information.
Contributed by J.N. Stepnisky, November 8, 1995