Working memory model

• Working Memory Model (WMM)

  Suggests that short-term memory (STM) is made up of the central executive, the phonological loop, the visuo-spatial sketchpad and the episodic buffer
• Central executive


  • An 'attentional process' with a very limited processing capacity, whose role is to allocate tasks to the 3 slave systems (phonological loop, visuo-spatial sketchpad, episodic buffer)
• Phonological loop


  • Processes auditory information and allows for maintenance rehearsal, made up of the articulatory process (stores the words you hear) and the phonological loop
• Visuo-spatial sketchpad


  • Combines the visual and spatial information processed by other stores, giving us a 'complete picture', divided into the inner scribe and visual cache, capacity around 4-5 chunks
• Episodic buffer


  • Integrates all types of data processed by the other stores (e.g. auditory, visual, spatial), the storage component of the central executive, crucial for linking short-term memory to long-term memory
• The central executive has not been precisely defined, the term 'process' is vague, and the central executive may be made up of several sub-components or even be part of a larger component itself in working memory, this lack of a comprehensive explanation for each component of WMM draws doubts about the accuracy of its depiction of working memory
• Shallice and Warrington's study of KF

  • KF had very poor short-term memory recall for auditory stimuli, but increased short-term memory recall for visual stimuli, suggesting the components of memory which process auditory and visual stimuli are separate (as described in the WMM through the phonological loop and the visuo-spatial sketchpad)
• Studies of dual-task performance


  • Decreased performance when participants undertake a visual and verbal task simultaneously, supports the idea that the central executive has a very limited processing capacity (as predicted by the WMM) and that the slave systems are in competition with each other for these tasks and resources
• Neuroscanning evidence, such as that provided by Braver et al


  • Demonstrated a positive correlation between an increasing cognitive load processed by the central executive (as marked by increasing task difficulty) and increasing levels of activation in the prefrontal cortex, supports the idea that the central executive has the role of allocating tasks to slave systems and has a limited processing capacity, suggesting the WMM is accurate in its mechanism of the central executive