The Working Memory Model Flashcards
Why did baddeley and hitch come up with the working memory model?
Baddeley and Hitch (1974) argued that the short term memory (as described by Atkinson and Shiffrin) was too simple. According the MSM, the STM is a unitary (single) store, holds limited amounts of information for short periods of time and carries out very little processing of this information.
Baddeley and Hitch argue that the STM is not a unitary store- it has sub stores and each is responsible for processing different types of information. Every component of the working memory is argued to have a limited capacity, and the components are relatively independent of each other.
They also disagreed with Atkinson and Shiffrin that the STM is simply a temporary store for information- they argued that the STM also processes information so tasks can be carried out. For this reason they renamed it working memory.
What are the four components of the working memory model?
Central executive
Phonological loop
Visuospatial sketchpad
Episodic buffer
What is the central executive?
The central executive has overall control. It processes information in all sensory forms, it directs attention to important tasks, monitors incoming information and decides which of its ‘slave systems’ are needed to complete them. It is involved in problem solving/ decision making. It has as a limited capacity- it cannot make many decisions at the same time.
Baddeley suggests that the central executive acts more like a system which controls attention processes rather than as a memory store. For example, two activities sometimes come into conflict, such as driving a car and talking. Rather than hitting a cyclist who is wobbling all over the road, it is preferable to stop talking and concentrate on driving. The central executive directs attention and gives priority to particular activities.
The central executive can be comparable to the job of an executive supervisor in an organization deciding on issues that require attention and others that should be ignored. It gathers information from and assigns tasks to its assistants – the phonological loop and visuo-spatial sketchpad – and from the library of information from long-term memory. However like any person in a company, the boss can only do a limited number of things at the same time- it has a limited capacity.
What is the phonological loop?
Temporarily stores and rehearses word-based information so is active whenever you read, listen or speak words. Stores this word-based information in the order in which it arrives. Can be subdivided into:
1) Phonological store- (linked to speech perception) acts as an inner ear and holds information in speech-based form (i.e. spoken words) for 1-2 seconds. Spoken words enter the store directly. Written words must first be converted into an articulatory (spoken) code before they can enter the phonological store.
2) Articulatory process- allows maintenance rehearsal of the word-based information - effectively it acts like an ‘inner voice’ rehearsing information from the phonological store. It circulates information round and round like a tape loop. This is how we remember a telephone number we have just heard. As long as we keep repeating it, we can retain the information in working memory.
The phonological loop has a limited capacity and duration.
Where is the visuospatial sketchpad?
Mental workplace for storing and manipulating a limited amount of visual and spatial information for a brief period of time. It is likely that the visuo-spatial sketch pad plays an important role in helping us keep track of where we are in relation to other objects as we move through our environment.
It has a limited capacity and duration. The VSS was later divided into:
- Visual cache: stores visual data.
- Inner scribe: Remembers the arrangement of objects in space.
What is the episodic buffer?
This was added in the year 2000 after it was recognized that the WMM does not allow for communication between the slave systems nor clearly explain how the LTM communicates with the different subsystems.
The episodic buffer acts as a ‘backup’ store which communicates with both long term memory and integrates the visual, spatial and verbal information processed by the other stores. It also records the order in which events (episodes) happen.
The episodic buffer is under the control of the central executive. It is linked to long-term memory and sends information to the LTM. However the episodic buffer has its own storages and processes.
What is the capacity and coding of the central executive?
Capacity is limited and coding is modality three, which means it can store information in any sense from
What is the capacity in coding of phonological loop?
Capacity is two seconds worth of what you can say, and coding is acoustic
What is capacity and coding of visuospatial sketchpad
Capacity is 3 to 4 objects and coding is visual
What is capacity and coding of the episodic buffer?
Capacity is about four chunks and coding is stores visual spatial and verbal information integrating it together
Describe the key study to support the working memory model
Key Study by Baddeley and Hitch (1976) to support the WMM
Aim: To investigate if participants can use different parts of working memory at the same time.
Method: Conducted an experiment in which participants were asked to perform two tasks at the same time (dual task technique) - a digit span task which required them to repeat a list of numbers, and a verbal reasoning task which required them to answer true or false to various questions (e.g. B is followed by A?).
Results in conclusion of baddeley and hitch study
Results: As the number of digits increased in the digit span tasks, participants took longer to answer the reasoning questions, but not much longer - only fractions of a second. Also, they didn’t make any more errors in the verbal reasoning tasks as the number of digits increased.
Conclusion: The verbal reasoning task made use of the central executive and the digit span task made use of the phonological loop.
Strength of the working memory model
1) One strength of the WMM is that it can account for dual-tasking- the fact that we can carry out two tasks at once if one is word-based and one is visual. This is because we can use the phonological loop to do the verbal task and, at the same time, the visuo-spatial sketchpad to do the visual task.
However- we find it hard to do two tasks at once if both are visual or verbal. This is because the phonological loop and visuo-spatial sketchpad have a limited capacity. This was shown by Baddeley and Hitch (1976). Dual‐task studies require participants to complete two tasks at the same time. In one condition, participants may be required to complete two acoustic‐based tasks, such as simultaneously remembering a series of digits and completing a verbal reasoning task. In another condition, participants may be required to complete one acoustic based task and one visual based task, for example, remember a series of digits and copying a drawing. When both tasks require the participants to use their phonological loop, their ability to perform the tasks is impaired. However, when one task requires the participant to simultaneously use their phonological loop (remembering a series of numbers) and the other requires their visuo‐spatial sketchpad (copying a drawing) then their performance is not impaired. Dual‐task studies provide evidence for the existence of multiple components within our STM and support the idea of a separate phonological loop and visuo‐spatial sketchpad.
2) Another strength of the working memory model is that it accounts for case studies like K.F (studied by Shallice and Warrington, 1970) which show that STM has different stores.
Patient KF, was injured in a motorcycle accident. Following his accident, KF was able to recall stored information from his LTM; however, he had issues with his STM. He was able to remember visual images, including faces, but was unable to remember sounds (acoustic information). This suggests that there are at least two components within STM, one component for visual information and one for acoustic information. The research into KF supports the WMM and the idea of two slave systems, the phonological loop and the visuo‐spatial sketchpad, therefore providing support to the WMM and the idea of a multi‐component STM system.
3) Another strength of the WMM is the brain scanning evidence to support the different components of the WMM. For example, D’Esposito et al (1995) used fMRI scans to test this and found that the prefrontal cortex was activated when verbal and spatial tasks were performed together but not when they were performed separately suggesting this brain area to be involved in the central executive. Similarly, PET scan show that different brain areas are activated during visual and verbal tasks.
4) A final strength of the working memory can explain how we carry our everyday tasks .e.g. verbal reasoning, comprehension, reading (both phonological loop), problem solving (central executive), navigation (visuo-spatial) far better than the MSM can. We can therefore say that it has greater face validity.
Weakness of the working memory model
1) One weakness of the WMM is that the exact role of the central executive remains unclear. It isn’t clear how it works and what it does. For example, it has been argued that the central executive directs attention and decides which slave system to carry out a task. However, this is very vague. Infact, it has been suggested that the central executive may consist of subcomponents. For example, Eslinger and Damasio (1985) studied EVR who had had a cerebral tumor removed. He performed well on tests requiring reasoning which suggests that his central executive was intact, however he had poor decision making skills (for example he would spend hours trying to decide what to eat) which suggests that in fact his central executive was not wholly intact. Therefore the explanation given for the central executive is vague and definitely more complex than presented.
2) Some of the evidence from brain-damaged patients is not necessarily reliable because it concerns single case studies who have had traumatic experiences. This makes it hard to make a generalization about ‘normal’ memory processing because these case studies are unique – for example, KF had a motorbike accident and thus suffered brain damage and problems with his memory – not all people who have problems with their memory have the same type of brain damage.
3) Furthermore, studies supporting the WMM especially the dual-task studies tend to be lab experiments where pps are required to identify the correct order of letters e.g. A follows B etc or recalling random sequences of letters. The findings from these studies may lack ecological validity and tell us nothing about how the working memory model works in everyday life. Furthermore, participants under highly controlled conditions tend to show demand characteristics e.g. they may guess the aim of the study and act in a way they believe will ‘fit the results’. For example, when pps are required to complete dual tasks which are not the normal everyday tasks, such as following a light with a pointer and a verbal reasoning task they may try harder as they are not used to it. This further questions the ecological validity of the studies and thus the WMM.
4) Finally, another issue with the WMM is that it only focuses on STM, and the link between the WMM and LTM is not fully explained. The WMM provides a detailed description of our STM, but no information on how information is processed and transferred from STM to LTM and back again. Therefore, the WMM is an incomplete model of memory and other theories/models are required to gain a complete picture of this complex cognitive phenomenon.
