Working memory model

• The working memory model was proposed by Baddeley and Hitch (1974). Unlike the multi store model, the working memory model focuses on the short term memory. They believed the short term memory to be both more complex and more active than suggested by the multi store model. The working memory model tries to explain how information is processed and temporarily stored in the short term (e.g. when reading a map or solving a maths problem).
• The central executive is the 'supervisor' in this management model. It processes all incoming information from the senses and manages our attention. It also has a limited capacity. Therefore, the central executive allocates the other subdivisions (known as 'slave systems) of this model to attend to the relevant information that the central executive cannot deal with.
• Visuo spatial sketch pad deals with visual and/or spatial material. For example, if you were asked how many cars are on your drive, you would visualise this in order to answer this. It also has a limited capacity (of around three/four objects). Since the publication of the original model it has been divided into two sub-components:

  • The visual cache = stores visual material.
  • The inner scribe = stores spatial information in terms of how stimuli is arranged.
• The phonological loop deals with auditory information and therefore codes acoustically. Again, it is subdivided into two components:

  • The phonological store = this is sometimes called the "inner ear' as it simply holds the words/sounds that we hear.
  • The articulatory control system = this is also known as the 'inner voice as it repeats the information we have listened to (a form of maintenance rehearsal). This keeps the information in the working memory for as long as we need it. It can hold no more than around 2 seconds worth of information (so also has a limited capacity).
• The episodic buffer was added in 2000 when Baddeley and Hitch revised their model. They saw the episodic buffer as a temporary store that accesses information from the two slave systems and records these events (i.e. episodes) to sequence this information. Due to the central executive's limited capacity, the episodic buffer can also help to store information from here whilst the central executive is dividing information to the two slave systems (but it does have a limited capacity too). The episodic buffer links the working memory to the long-term memory.
• limitation of research such as that above into this model is that it often lacks ecological validity. This is because the procedures need to be very controlled in order to eliminate extraneous variables. In doing so, the tasks are often very artificial (e.g. pressing keys or random word patterns) so do not accurately represent everyday 'dual-tasks'. This is a limitation because the model may have limited generalisability if the research that helped to develop this has low external validity.
• Strength - KF. Warrington and Shallice (1970) noted that KF had experienced a serious motorcycle accident. This caused him to have severe damage to his STM (his digit span was only 2), although his LTM remained intact. Upon closer inspection, KF's STM only struggled with verbal material. His STM for visual material was fine. It would appear that his phonological loop had been damaged by his accident, whereas his visuo-spatial sketchpad escaped such damage. This supports because the case suggests that the STM is subdivided like the working memory model suggests.
• Strength - Evidence from dual-task studies can also be used to support the model. Carried out visual and verbal task at same time. Robbins had participants choose chess moves from a board (VSS) and some participants had to do this task whilst also repeating the words 'see saw' (using the phonological loop) or pressing keys in a clockwise fashion (VSS). Those who had to say 'see-saw' whilst making these chess moves performed better than those who had to press keys in a clockwise fashion. This supports the idea that the phonological loop and VSS are two separate stores with limited capacities.
• Limitation - criticism towards nature of the central executive. Parkin argues that it is not well defined to the point of being unfalsifiable and goes so far as to say it doesn't exist. Baddeley and Hitch were never clear on the exact role and function of the central executive. It seems to be capable of doing so many different things that it seems simplistic to say that it is a single component on its own. Many psychologists feel that it has subcomponents just as the other parts of the model do. This is a limitation as it questions the validity of this part of the model.