Memory: working memory model Flashcards
Describe the central executive
The central executive is essentially an attentional process that monitors incoming data, makes decisions and allocates slave systems to tasks. The central executive has a very limited processing capacity.
(1) Decided which component is needed for a particular task;
(2) Coordinates retrieval of info from our LTM;
(3) Decided what our working memory pays attention to;
(4) Switched our attention between tasks.
Research to support central executive (Bunge 2000)
Research → Bunge 2000
Used fMRI scans to see which part of the brain were most active when Pt’s were doing 2 different tasks (reading a sentence and recalling the final word in a sentence)
The same brain areas (PREFRONTAL CORTEX) were active in dual or single tasks conditions. What was especially interesting was that the activity in this area became increased as the task became harder.
BUT, more activation shown in dual task area = increased attentional demands placed on the central executive
This research shows… that when extra demands are placed on the central executive, more activity is shown through brain scanning devices
Describe the visuospatial sketchpad
The second slave system is the visuospatial sketchpad (VSS).
The VSS stores visual and/or spatial information. E.g., visualising how many windows you have in your house. VSS has a limited capacity of around 3-4 objects. The VSS is subdivided into:
(1) The visual cache which stores visual data (and info about form and shape);
(2) The inner scribe which records the arrangement of objects in the visual field.
Research to show support for visuospatial sketchpad (Brooks 1968)
Similar to a dual process technique, Pt’s were made to mentally visualise a letter e.g. K or F They were then asked questions about it e.g. does it have right angles?
They were asked to respond in 1 of 3 ways.
1) Speaking aloud;
2) tapping (once for yes, twice for no); 3) pointing to a YES or NO sign.
Pt were faster and more accurate when responding verbally or tapping. This was because when using the same limited capacity component for the same task i.e. the VSS, they interfere with each other. I.e. showing the VSS is a limited processor
This research shows that… there is support for the visuospatial sketchpad as a processor within working memory, and also highlights the effects of doing two tasks using the same or different components, showing the two separate processing units exist alongside each other.
Describe the phonological loop
One of the slave systems is the phonological loop (PL). It deals with auditory information (i.e., coding is acoustic) and preserves the order in which the information arrives. The PL is subdivided into:
(1) The phonological store which stores the words you hear (hold spoken words for 1.5-2 seconds- limited capacity);
(2) The articulatory process which allows maintenance rehearsal. The capacity of this loop is believed to be two seconds worth of what you can say.
Research to support phonological loop (Baddeley 1975)
Research → Baddeley (1975)
Evidence for the word length effect and PL
Pt’s recalled more short words in serial order than longer words, supporting the idea that the capacity of the PL is set by how long it takes to say words rather than the actual number. This means aspects of the WMM appear correct and credible
This research shows that… the phonological loop can hold the number of items that can be said in about 2 seconds, so is more affected by length of words rather than number of words.
Describe the episodic buffer
The third slave system is the episodic buffer. This was added by Baddeley in 2000.
DESCRIPTION:
It is a temporary store for information, integrating the visual, spatial and verbal info processed by other stores and maintaining a sense of time sequencing - basically recording events (episodes) that are happening.
It can be seen as the storage component of the central executive and has a limited capacity of about four chunks (Baddeley 2012). The episodic buffer links working memory to LTM and wider cognitive processes such as perception.
Research to support episodic buffer (Alkhalifa 2009)
Research → Alkhalifa (2009)
Alkhalifa reported on a patient with severely impaired LTM who demonstrated STM capacity of up to 25 prose items, far exceeding the capacity of both the PL and the VSS.
This research shows that… there is evidence the episodic buffer exists and it holds items in working memory until they are recalled.
Describe WMM with evidence
The working memory model was an expanded version of the multistore model by Baddeley & Hitch, in which they focused on the short-term memory processes and mechanisms.
They proposed that working memory is comprised of 4 key components, each dealing with specialist memories and brain areas. Firstly, the central executive is charged with delegating out the attentional resources of the model.
This involves sending resources to two ‘slave systems’, whereby individuals can pay attention to tasks being directed to them with a view of completing them.
One of these systems – the visuo-spatial sketchpad – deals with visual/spatial information within an individual’s vicinity.
An example of a task needing this system would be speed perception of a car and how fast it is moving. Furthermore, attentional resources can also be sent to the phonological loop, largely responsible for the processing of auditory information. Baddeley suggested that the phonological loop could retain auditory information for roughly 1.5 seconds. Combining information from these two slave systems is the episodic buffer, added by Baddeley in 2000 after criticisms of a lack of capacity in his model. The episodic buffer combines information from these two systems into one unitary pack (or memory) before being sent down to the long-term memory. The model emphasises the active nature of memory, citing that memory is more than simply recall of information which had been posited in previous models.
Evaluation of WMM : research (Brooks)
There is supporting research for the working memory model.
For example, Brookes
Similar to a dual process technique, Pt’s were made to mentally visualise a letter e.g. K. They were then asked questions about it e.g. does it have right angles? They were asked to respond in 1 of 3 ways, either visually or acoustically
Found much easier when not using the same channel . This was because when using the same limited capacity component for the same task i.e. the VSS, they interfere with each other.
This suggests… the existence of separate slave systems. Backing this research up with scientific findings improves both the validity and the credibility of the theory
Evaluation of WMM : research lacks mundane realism
However, one problem with the WMM is that much of the research evidence supporting the model comes from artificial lab experiments into memory with artificial materials.
For example, in everyday life we form memories related to all sorts of useful things - people’s names, faces etc. But a lot of the research studies that provide support for the WMM use digits, letters and random artificial tasks. For instance, Brooks research had Pt’s describing the angles of the letter F. This task is completely unrealistic and therefore lacks mundane realism.
This implied the research evidence supporting the WMM lacks credibility, which therefore reduces the usefulness of the theory.
Evaluation of WMM: research (KF)
However, there is further naturalistic research support for the WMM from the case of KF.
Patient KF had a motorbike accident in his 20’s. The parietal and occipital area of his brain was damaged. This affected his STM and he was only able to recall one or two items acoustically. However, his STM could retain info if it was presented visually. Hence, KF’s phonological loop was impaired, yet his Visual-spatial sketchpad was intact.
This provides even further support for the components of the WMM, increasing the credibility of the theory.
Evaluation of WMM : theoretical flaws
However, the WMM still contains several theoretical flaws that limit its use.
For instance, the WMM may still be oversimplified. The nature of the central executive is still unclear - it might not be a single entity such as shown in the case of EVR. This patient had a brain tumour removed which resulted in poor decision-making skills but good reasoning skills. The CE needs to be more clearly specified than just being simply ‘attention’.
This suggests there may in fact be separate components within the central executive, therefore the WMM hasn’t been fully explained yet.
Evaluation of WMM : applications (schiz)
The concept of the WMM has useful practical applications.
Park et al. (1999) concluded that patients with schizophrenia (a mental illness) tend to have problems with working memory that can be identified on dual tasks as used in the WMM. Hence, schizophrenia can therefore be diagnosed on the basis of testing an individual’s working memory.
This implies that the WMM has useful applications to society at large.
Evaluation of WMM: applications
This model could have massive practical applications for society given that we apparently possess a working model.
For example, it helps explain ADHD by explaining that a subset of the population may have naturally poorer working memories and attention spans.
Therefore, by using working memory improvement techniques such as memory training, we may be able to alleviate some of the symptoms of this disorder. This may further take away the need for harmful pharmacological treatments such as Ritalin with more natural psychological treatments being made available.
Therefore, it can be said this theory has positive tangible effects in society.
