<P> Baddeley & Hitch's argument for the distinction of two domain - specific slave systems in the older model was derived from experimental findings with dual - task paradigms . Performance of two simultaneous tasks requiring the use of two separate perceptual domains (i.e. a visual and a verbal task) is nearly as efficient as performance of the tasks individually . In contrast, when a person tries to carry out two tasks simultaneously that use the same perceptual domain, performance is less efficient than when performing the tasks individually . </P> <P> A fourth component of Baddeley's model was added 25 years later to compliment the central executive system . The third' slave system' was designated as episodic buffer . It is considered a limited capacity system which provides temporary storage of information capable by conjoining information from the subsidiary systems, and long - term memory, into a single episodic representation . </P> <P> The central executive is a flexible system responsible for the control and regulation of cognitive processes . It directs focus and targets information, making working memory and long term memory work together . It can be thought of as a supervisory system that controls cognitive processes making sure short term store is actively working and intervenes when they go astray and prevents distractions . </P> <P> It has the following functions: </P>

Baddeley's model of working memory psychology definition