Working memory model

What is the working memory model

Baddeley and Hitch (1974) thought the multistore model underestimated the importance of STM. They claim the STM isn’t just a ‘waiting stage’ for information before transferring it to the LTM, it is more complex and active then that. They therefore called STM ‘Working memory’. Working memory holds all the material you are thinking about at any moment. Working memory sends and receives information to and from out LTM. Information in working memory is fragile and easily lost so it must be kept active to be retained. The model is a multi-component system with several connecting parts which can work together or independently.

why can’t 2 tasks using the same component happen at one in the working memory model

Each part has limited capacity

Central executive

Controls the activity of working memory. Direct attention to particular tasks determining any time how resources are allocated to tasks . Other modules of ‘slaves’ to this one. Has a limited capacity and therefore cannot attend too many things at once. Manages what goes on by directing attention towards the most important information at the expense of other less important information.

Phonological loop

Auditory store which rehearses sound based information to prevent decay it has a limited capacity and consists of two parts:

• Phonological store: Deals with perception of sound including speech it holds the words you is known as the inner ear

• Articulatory loop: Known as in a voice. It is a verbal rehearsal system used to prevent the decay of verbal material by saying things over and over until it’s spoken aloud The words are suddenly repeated and it has a duration of two seconds. Thus its capacity is as much information we can rehearse in two seconds.

The visuo-spatial sketchpad

Author referred to as the inner eye as coding is visual. Visual and spatial information is temporarily stored here. This is used when you have to plan a visual and/or spatial task. It is the mental rough paper that you might use when doing mental rough paper. It has a limited capacity of 3-4 objects.

Episodic buffer

25 years later Baddeley (2000) added a third slave system as he realised there was no general staff for information. Hold information that includes both visual and sound based content. It acts as a temporary store and integrates information from all other components. It has a capacity of about four chance information it records episodes as they are happening so it has a sense of time and consent information to long-term memory.

Outline of the working memory model

The working memory model claims that STM is a working memory which actively holds all material you were thinking about at any moment it suggests that there are multiple components to working memory. The central executive controls the activity of working memory and direct attention to particular tasks it has a limited capacity. The phonological loop is an auditory store which house is sound based information it consists of the phonological store which holds the words you hear and is known as the inner air and the articulatory loop which is the verbal rehearsal system and is known as the inner voice. The articulatory loop has a limited capacity of what we can rehearse in two seconds. The visuo-spatial sketchpad codes visual and spatial information and it’s known as the inner eye it has a capacity of 3 to 4 objects 25 years of the original model was proposed. The episode of buffet was added. This is a general store of information and records episodes of your life. It has a capacity of four chunks.

Application of working memory

The phonological loop can explain why if you’re watching the TV and your mother tries to talk to you you find it difficult to listen to both at the same time. This is because of the limited capacity of the phonological loop.

Mental arithmetic involves using the visor-spatial sketchpad to mentally add numbers in your head. When doing very long sums the capacity of 3 to 4 objects is exceeded and so it is very difficult to do such sums

evaluation of working memory model summary

• dual task performance

• brain imaging

• studies on word length effect

• lack of clarity over central executive

• artificial tasks

evaluation of working memory model - dual task performance

Support for the distinction between the different parts of WMM is supported by studies of dual-task performance. Performance of two simultaneous tasks requiring the use of two separate systems (i.e. a visual and a verbal task) is nearly as efficient as performance of the tasks individually. In contrast, when a person tries to carry out two tasks simultaneously that use the same system, performance is less efficient than when performing the tasks individually. This supports the model as it demonstrates that the components of WMM are separate, and that they have limited capacity. See study below for research on dual task performance:

In their experiment, Baddeley and Hitch had two tasks:

• Task 1: Ps completed a verbal reasoning task in which they were shown letters
  AB or BA and a statement describing the order. Participants were required to state whether the order was true or false as quickly as possible. This occupies the central executive.

• Task 2: This could be one of three different 'tasks'.

1. Participants were required to repeat 'THE THE THE THE THE' over and over again. This occupies the articulatory loop

2. Participants had to say random digits out loud. This occupies both the articulatory loop and the central executive.

3. Participants were not required to complete a second task.

The results showed that when task 1 (the verbal reasoning task) was combined with version A or version C of the second task, performance on task 1 was not affected.

Participants were just as fast at making the true or false decision. Therefore, when different components are• used, performance on the tasks is not adversely affected

When combined with version B of task 2, speed dropped significantly. This shows that doing two tasks that use the same component of memory (central executive used for the verbal reasoning test AND to generate the random numbers) causes difficulty.

evaluation of working memory model - brain imaging

Brain imaging studies suggest that tasks needing different parts of the working memory model use different parts of the brain. This is evidence that there are separate systems at work as the WMM suggests. For example if a person is given a task that uses the phonological loop (like reciting a poem) then one brain area is active, but if they are asked to do a task that uses the visuo-spatial sketchpad (such as mentally picturing their route from their house to town) then a different brain area is active. This is evidence that the phonological loop and VSS are separate stores, which supports the model.

evaluation of working memory model - studies on word length effect

A strength of the model is that the role of the phonological loop in rehearsal has been supported by studies of the word length effect i.e. the tendency to immediately recall short words better than long words. Working memory explains this by saying the articulatory loop has a limited time capacity (what we can rehearse in 2 secs) & as short words take less time to say we can remember more of them. Therefore, there is evidence supporting the limited capacity of the articulatory loop.*

evaluation of working memory model - lack of clarity over central executive

Cognitive Psychologists argue that there is a lack of clarity over the central executive. Baddeley recognised this himself and said 'The central executive is the most important but the least understood component of working memory. It has been argued that the central executive needs to be more clearly explained rather than simply being 'attention'. In addition, most research focuses on the 'slave' components but there is little experimental support for the central executive; it is said to have limited capacity but the actual capacity is not known.

evaluation of working memory model - artificial tasks

The WMM is supported by many lab experiments e.g. dual task, word length effect. However, a problem with the lab experiments used to support the WMM is that they use very artificial tasks such as asking Ps to repeat the the the. This is not reflective of how we use our memory in real life, meaning that the studies lack ecological validity and results will not generalise to real life situations. Therefore, if there are issues with the supporting studies they may not be valid for supporting evidence for the WMM.