Working Memory model

• Working Memory Model


  A representation of short-term memory (STM). It suggests that ASTM is a dynamic processor of different types of information using sub-units coordinated by a central decision-making system.
• Central Executive (CE)


  • The component of the WMM that co-ordinates the activities of the three subsystems in memory. It also allocates processing resources to those activities.
• Phonological Loop (PL)


  • The component of the WMM that processes information in terms of sound. This includes both written and spoken material. It's divided into the phonological store and the articulatory process.
• Visuo-Spatial Sketchpad (VSS)


  • The component of the WMM that processes visual and spatial information in a mental space often called our 'inner eye'.
• Episodic Buffer (EB)


  • The component of WMM that brings together material from the other subsystems into a single memory rather than separate strands. It also provides a bridge between working memory and long-term memory.
• Central Executive (the boss)

  • Coding: modality free (it can deal with information from any of the senses)
  • Capacity: very limited (it can only pay attention to a small amount of stimuli)
  • The central executive is the main component of the WMM, it drives the whole system.
  • It decides what we selectively pay attention to e.g. how important new information is and how much attention should be paid to it.
  • The CE is often referred to as the boss of working memory as it has control over the three components (or slave systems). It sends information to the relevant stores/slave systems (e.g. phonological loop and the visuospatial sketchpad).
  • The central executive is active when dealing with cognitive tasks such as mental arithmetic, decision making and problem solving. It allocates processing resources to these activities.
• Phonological Loop: Slave System 1 (auditory information)


  • Coding: acoustic (it deals with auditory or sound information)
  • Capacity: limited (it can only hold what can be said in two seconds)
  • It preserves the order of information e.g. when discussing a film you have seen, you will use the phonological loop to rehearse the key points you want to share. It also contributes to our learning of sounds of language.
  • It accesses LTM to store and retrieve information about language sounds. This allows us to develop our vocabulary as children and, in a foreign language, as adults.
  • The phonological loop can be divided into two parts: Phonological Store (Inner Ear) - Holds words that you hear in a speech-based format, Articulatory Control System (Inner Voice) - It allows for maintenance rehearsal (repeating sounds or words in a loop to keep them in working memory while they are needed).
• The Visuo-Spatial Sketchpad (VSS): Slave System 2 (visual + spatial information)


  • Coding: visual and spatial (the things we can see)
  • Capacity: limited (approximately 3-4 objects)
  • The visuo-spatial sketch pad (VSS) stores and manipulates visual and/or spatial information (the relationship between things)/ For example if you are asked to work out how many windows there are on your house you visualise it.
  • The VSS can access LTM and retrieve visuo-spatial information. For example, if asked to think of something you sit on, an image of a chair can be retrieved from LTM.
  • Logie (1995) subdivided the VSS into: Visual Cache - Stores information about form and colour (what something looks like), The Inner Scribe - Records their spatial position in the visual field (where something is). It rehearses and transfers information in the visual cache to the CE.
• The Episodic Buffer: Slave Sytem 3 (added to the model in 2000)


  • Coding: modality free (it can deal with information from any of the other slave systems)
  • Capacity: limited (it can only hold around four chunks of information)
  • This is a more general store. It acts as a 'back up' store which communicates with both long-term memory and the components of working memory
  • The episodic buffer takes all the information from the other components and forms a memory of what is happening. It is dedicated to integrating the visual, spatial and verbal information processed by other stores and maintaining a sense of time sequencing; like a recording events (episodes) that are happening. For example, a scene from a TV programme will comprise of visual information, speech, sounds and movement.
  • The episodic buffer links working memory to LTM and wider cognitive processes such as perception.
• Working memory is the ability to hold information in mind while performing tasks.
• Episodic Buffer


  Slave System 3 (added to the model in 2000)
• The original model was updated by Baddeley (2000) after the model failed to explain the results of various experiments. An additional component was added called the episodic buffer.
• Episodic Buffer


  • Modality free (it can deal with information from any of the other slave systems)
  • Capacity is limited (it can only hold around four chunks of information)
  • It acts as a 'back up' store which communicates with both long-term memory and the components of working memory
  • It takes all the information from the other components and forms a memory of what is happening. It is dedicated to integrating the visual, spatial and verbal information processed by other stores and maintaining a sense of time sequencing; like a recording events (episodes) that are happening
  • It links working memory to LTM and wider cognitive processes such as perception
• Musical Memory

  The working memory model excels at explaining verbal and visual memory, but music throws a wrench in the works. Studies like Berz (1995) showed people could listen to music (auditory task) while doing other auditory tasks without issue. This challenges the model's idea of a single, overloaded auditory store. However, the model's supporters might argue music has its own dedicated processing system that wouldn't compete with the one for speech. More research is needed to see how musical memory fits into the working memory model's framework, or if it needs an overhaul.
• The working memory model isn't just supported by brain damage. Dual-task experiments also provide evidence.
• Dual-task experiment by Baddeley et al. (1975)


  1. Participants tracked a light

  2. Participants imagined letters (both visual tasks)

  3. Participants tracked the light while repeating words (verbal task)
• Dual-task experiment findings


  • Participants struggled more to track a light while imagining letters (both visual tasks) compared to tracking the light while repeating words (verbal task)
• Working memory model explanation

  Proposes separate systems: a visual scratchpad and a verbal loop. Since both imagining letters and tracking the light are visual, they compete for resources, leading to poorer performance.
• Some dual-task studies challenge the strict separation idea.
• Tasks that might require both visual and verbal processing

  • Following spoken instructions while navigating a maze
• More research is needed to see how the working memory model applies to real-world situations where tasks often combine different information types.