The concept of working memory was suggested by Baddeley and developed by Baddeley and Hitch, among others. They offered this as a structure to replace short-term memory. Working memory has a three-component memory system. The main part is the Central Executive or Executive control system and is in charge of directing attention and mental resources, of starting the rehearsal procedure when necessary, and of making decisions. It further carries out most of the reasoning task. Second is a slave system, subordinate to the executive, called the Articulatory Loop, the element responsible for memory span performance. A second slave system is the Visuo-Spatial Sketchpad. The slave systems can operate on their own once they are triggered by the executive, and they will not disrupt the functions of the executive at all (Ashcroft, 1994, 185-186).
One of the experiments conducted by Baddeley and Hitch was intended to test the articulatory loop. A) They asked subjects to perform the standard reasoning task while doing one of three "articulatory suppression" tasks. One of these tasks involved making fast repetition of the word "the," the idea being that doing this would not require memory as such but would consume the articulation resources of the articulatory rehearsal loop. The repetition of "the" should suppress any articulation that is a normal part of the reasoning process. The second suppression task involved the rapid repetition of the sequence "one two three four five six." The last task required a memory span procedure with strings of six digits, and the subject had to repeat aloud the random digit string over and over while answering the reasoning sentences. B) The theory being tested was that of working memory, specifically the element known as the articulatory loop. C) Baddeley and Hitch found the same results on language comprehension tasks as on reasoning problems--holding six digits in memory significantly disrupte...