Working Memory Model

Who proposed the WMM

Baddeley and Hitch 1974

Outline the WMM

• Proposed by Baddely and Hitch in 1974

• A representation of STM and suggests it's a dynamic processor of different types of information using subunits, coordinated using a central decision making system

• Baddeley & Hitch criticised the multi-store model (MSM) as overly simplistic, particularly with regard to short-term memory (STM)

• The WMM explains memories related to working on tasks that require immediate memory formation and concerned with the mental space that is active when we are temporarily storing information

What are the 4 components of the WMM

• Episodic buffer

• Phonological loop

• Visio-spatial sketchpad

• Central executive

What is the role of the central executive (ce)

• The role of the central executive (CE) is to focus attention on the most important tasks that need attending to in the current moment

• The CE coordinates the three other components of the WMM by allocating them to different tasks

• The CE has limited capacity and cannot store information

What are 'slave systems’

Each of the three components, phonological loop (PL), visuo-spatial sketchpad (VSS) and episodic buffer (EB) are known as 'slave systems'

• they are coordinated by the CE by allocating them to different tasks

What is the role of the phonological loop

• The phonological loop (PL) slave system is responsible for coordinating auditory information

  • coding is therefore acoustic

• The PL preserves the order in which acoustic information is processed

• The PL has a limited capacity

What are the two divisions of the phonological loop

• The phonological store: this component stores the words you hear

• The articulatory process: this component stores written words and allows maintenance rehearsal

  • capacity is 2 seconds worth of what you can say

What is the role of the Visio spatial sketchpad

• The visuo-spatial sketchpad (VSS) component of the WMM is the slave system responsible for storing visual and/or spatial information

• Information is stored temporarily in the VSS

• The VSS has a limited capacity

What can the VSS be divided into

• Visual cache - stores visual data

• Inner scribe - record the arrangement of objects within the visual field

What is the role of the episodic buffer

• The function of the episodic buffer is to receive information fromthe CE, PL and VSS and to integrate this information into 'episodes'

• The EB records information as episodes, so that it is time-sequenced

• Information is stored temporarily by the EB

• The EB is separate from LTM, but it forms an important stage in long-term episodic learning

• The capacity of the EB is limited

What are the strengths of the WMM

Clinical evidence

• The case study of KF (Shallice & Warrington, 1970) offers support for the WMM

• KF suffered a brain injury after which his STM was severely impaired

• KF struggled to process verbal/auditory information but his ability to recall visual information was unaffected (PL damaged but VSS was still intact)

• This is evidence that there are different slave systems in the working memory which code for verbal/auditory information and visual information

Dual task performance

• Baddely et al 1975 supports separate existence of the VSS

• When his Ps carried out a visual and verbal task at the same time, the performance on each was similar to when they did the tasks separately

• This is because both visual systems compete for the VSS, but no competition when performing a verbal and visual task together

• This shows there must be a separate subsystem (the VSS) the processes visual input

What are the limitations of the WMM

Counterpoint to clinical evidence (KF)

• It is unclear as to wether KF had other cognitive impairments (apart from damage to the phonological loop

• E.g accident was caused by a motorcycle accident and may have affected his cognitive performance quite apart from any other brain injury

• This challenges clinical evidence of people with brain injuries that may have affected many different cognitive systems

Nature of the central executive (CE)

• There is a lack of clarity over the role of the CE

• This lack of detail may be due to the fact that the CE is very difficult to operationalise and measure

• There may be more than one central component to the CE but to date, this has not been established with empirical evidence

• This means that the CE is an unsatisfactory component and challenges the integrity of the WMM