Cognitive Load Theory & the Working Memory Model (DP IB Psychology): Revision Note

The working memory model (WMM)

• The Working Memory Model (WMM) was devised by Baddeley & Hitch (1974) as a more dynamic and flexible model of memory

• The WMM focuses on short-term memory (STM) only; there is no provision made for the functions or types of long-term memory it only aims to explain the ‘here and now’ of memory

• The WMM sees STM as a complex information processor rather than as a static unitary store

• The WMM is composed of four units:

  • the central executive (CM)

  • the phonological loop (PL)

  • the visuospatial sketchpad (VSS) with the

  • episodic buffer (EP), which was added much later on in 2000

The Working Memory Model

The central executive (CE)

• This is the driving force of the WMM as it decides which tasks are to be assigned to which specific slave systems, rather like the managing director of a company

• The CE is not so much a memory store but a ‘command centre’, as it plays a key role in controlling the processes of working memory

• Although the CE is probably the most important element of the WMM it is very difficult to test (unlike the VSS and the PL)

• The CE decides which information to pay attention to and which information to ignore and it then directs the slave systems accordingly

The phonological loop (PL)

• This slave system attends to and organises acoustic information in the form of spoken or written information

  • E.g., written words are encoded via vocalising them in the mind so that visual information becomes acoustic information

• The PL can be divided into two parts:

  • the phonological store

  • the articulatory control system

• The phonological store is the ‘inner ear’ of the WMM as it processes and stores acoustic, speech-based information for a very short duration (a couple of seconds)

• The articulatory control system translates written words into speech so that they can then be kept in the phonological store in a kind of loop or ‘holding pattern’

  • E.g., repeating a phone number over and over again until we can put it into our phone

The visuospatial sketchpad (VSS)

• This slave system attends to and organises visual and spatial information

  • E.g., the colour of a flower, the arrangement of windows and doors in a house

• The VSS is used when someone recognises a friend or when they give directions to a stranger

• The VSS can be divided into two parts:

  • the visual cache

  • the inner scribe

• The visual cache is the ‘inner eye’ of the WMM as it stores information about form and colour

  • E.g., a purple triangle, a tall white vase

• The inner scribe contains spatial and movement-related information

  • E.g., how to get from one side of a crowded room to the other

• The inner scribe rehearses information which is then stored in the visual cache

The episodic buffer (EB)

• This slave system was added to the model in 2000 as a way of acknowledging that the CE and slave systems have to communicate with LTM in order to be able to function effectively

  • WM must be able to respond to the current situation – not being able to remember which side of the road to drive on, for example, could cause all sorts of problems!

• The EB arranges information into ‘packets’

  • When required it moves this information to the slave systems in a set sequence

    • Events occur continuously rather than seeming out of joint (e.g., if you are having a conversation, you see the other person speaking at the same time as their lips move)

Cognitive load & the WMM

• Cognitive load theory (CLT) proposes that working memory has a limited capability for processing new information

• CLT suggests that learning and task success are impaired when WM is overloaded, as it does not have the capacity to handle too much competing information at any given moment

  • In other words, the load is too heavy for WM to cope with

• A demonstration of CL can be seen in dual-task studies which test the assumptions of the WMM

• A dual-task procedure is where participants perform two tasks simultaneously to investigate how they compete for cognitive resources

  • E.g., drawing a picture whilst listening to music/drawing a picture whilst trying to mentally visualise different shapes

• This method is used to assess the effect of divided attention on performance and to understand cognitive load

Research which supports cognitive load theory & the WMM

Baddeley et al. (1973)

Aim:

• To investigate the existence of the VSS and the PL as separate components in the Working Memory Model by using a dual-task activity (dual-task study)

Procedure:

• A dual-task lab experiment in which participants were given a tracking task (following a spot of light with a pointer around a circular path) while imagining block capitals in their heads, such as H, T, F and E.

  • Condition A:

    • Participants were asked to start at the bottom left-hand corner of the path and to begin tracking the light

    • They were asked to give verbal yes/no responses about features of an imagined block capital (e.g., does it have a top/middle/bottom line?)

    • So, if the participant was thinking of the letter ‘F’, then they would respond that yes, it had a top and a middle line but no bottom line

    • They did this while tracking the spot of light

  • Condition B:

    • The participants were asked to track a light and were then told to imagine one of the letters, ‘F’ for example

    • While they were tracking the pattern, they were asked, ‘Does this letter have a top line/middle line/bottom line in it?’

    • They were asked to silently visualise letter features while tracking the light

Results:

• Participants in condition B experienced great difficulty in tracking the spot of light and, at the same time, accurately identifying in their head whether the letter had a top/middle/bottom line

• Tracking and letter imagery tasks were competing for the limited resources of the VSS, whereas the tracking and verbal tasks in condition 1 (responding verbally whilst visualising the letter) used separate components: the VSS and PL

Conclusion:

• There may be separate slave systems – the VSS and the PL – which operate in working memory

• Overloading one of the slave systems with two tasks means that it cannot function properly

Evaluation of cognitive load theory & the WMM

Strengths

• Dual-task research is replicable as most studies are lab-based and use standardised procedures which can be replicated to check for consistency (reliability)

• The study focuses on the dynamic nature of working memory, as it demonstrates how memory is used in the moment in order to complete a complex task

Limitations

• As the participants had to visualise each letter in their heads, there is the possibility that they became distracted and thought of other things, which would mean that the study lacks validity

• Extraneous variables might confound the findings of dual-task research

  • E.g., some people have naturally better memories or concentration spans than others; some people are more visual or more auditory learners; some people are dyslexic/dyspraxic

    • This means that the findings may not be due to cognitive load; thus, the research may not account for individual differences

Link to concepts

Perspective

• The WMM provides a much more detailed and dynamic model of STM than the MSM

• It explains how different processes in memory

  • E.g., response to acoustic and visual information occur at the same time rather than conceptualising memory in a linear, static fashion

• Most researchers will only refer to 'working memory' rather than 'short-term memory', as the term evokes the 'here-and-now' nature of WM

  • It is working hard to process a lot of information using restricted duration and capacity

Causality

• There is very little insight or evidence as to how the CE functions in terms of directing attention towards the slave systems

• The CE is almost impossible to test, so the concept of the CE remains hypothetical whereas the VSS and PL are easier to measure and test

• Additionally, by not properly explaining the role of LTM in WM means that the WMM is limited and ignores key factors as to how LTM and the EB combine to facilitate the operations of WM