The Working Memory Model (WMM)

What is the Working Memory Model?

• By Baddeley & Hitch, to replaced the STM store of the MSM due to the simplification of the STM, developed by dual task study

• STM is more complex

• STM is an active processer, holding multiple different types of information simultaneously while being worked on

Draw a diagram of the WMM.

Outline the Central Executive.

• Supervisory function: Controls attention, receives sense information & filters this before passing on to relevant slave systems. (i.e. controls slave systems)

- Used for reasoning tasks

• Limited capacity: 4 +/- items (3-5)

- Can only work on one type of information at a time but can switch between different inputs

• Encoding: Can process information from any sensory modality

Outline the phonological Loop.

• Stores: Verbal information in a speech based form

1) Primary acoustic/phonological store = The inner ear, holding words recently heard

2) Articulatory process = The inner voice (used for maintenance rehearsal), holds information via sub-vocal repetitions

• Limited capacity: What can be said in 2 secs

Outline the Visuospatial Sketchpad.

• Stores: Visual & spatial information

1. Visual cache: A passive store of colour & form

2. Inner scribe: Active store holding the relationships between objects in 3D space

• Limited capacity: Holds 3-4 objects at a time

Outline the Episodic Buffer.

• Holds & integrates information from the VSS, CE & PL (all of them)

• Temporary storage, sends information to LTM

• Can hold any type of information (any code)

Outline Baddeley & Hitch (1974) research supporting the WMM.

PROCEDURE:

• Lab experiment, repeated measures

• Participants asked to perform 2 tasks at the same time (dual task technique)

• A digit span task (repeat a list of numbers) & a verbal reasoning task (true or false Qs)

RESULTS:

• As numbers increased, participants took longer to answer reasoning questions (only by a fraction of a second)

• As numbers increased, they didn’t make any errors in the VR task

CONCLUSION:

• VR task made use of the central executive & the digit span task made use of the phonological loop

• It’s easier to do 2 tasks at the same time if they use different processing systems (verbal & visual) than if they use the same slave system

Outline the case of KF supporting the WMM.

• KF had brain damage following motorcycle accident which affected his STM

• His impairment was mainly for verbal information, his memory for visual information was largely unaffected

- e.g. could remember faces but not sounds

• Shows there’s separate STM components for visual information (visuospatial sketchpad) & verbal information (phonological loop)

Outline Prabhakaran et al 2000 research in existence/location of episodic buffer.

PROCEDURE: 

• Lab experiment, independent designs

• Used brain imaging FMRI scans

• Participants asked to complete tasks w/ equal amounts of spatial & verbal information (dual task investigation)

RESULTS:

• Condition 1 = more activation in the prefrontal cortex when information integrated

• Condition 2 = posterior brains region active when not integrated 

CONCLUSION:

• Suggest EB exists & is in the prefrontal cortex when information integrated

• A brain region specialised in the combination & temporary storage of visual & verbal information

• Biological evidence for existence of EB

Outline Hunt (1980) research in Central Executive.

PROCEDURE:

• Lab experiment, repeated measures design

• Participants performed 2 tasks

1) Psychomotor task (moving lever with their hand)

2) Visual Intelligence task (reasoning about visual patterns)

- Tasks performed either alone or together (1 or 2 or both)

RESULTS:

• When tasks done together performance got worse on the psychomotor task

• As the visual problems got harder, performance on the psychomotor task deteriorated

CONCLUSION:

• Proves central executive has limited capacity

Outline Baddeley, Grant, Wright & Thompson (1973) research into visuospatial sketchpad.

PROCEDURE:

• Lab experiment, independent measure, dual-task technique

1) A primary tracking task (following spot of light w/ a pointer) whilst simultaneously doing secondary visual imagery task

2) Primary tracking task + verbal imagery task

- In the 2nd visual tasks, participants had to imaging the letter E & classify the corners in the letter

RESULTS:

• Participants 1 found it difficult to do both primary tracking & secondary visual task

• Participants 2 found it easy to do primary tracking + verbal imagery task

CONCLUSION:

• Condition 1 - the 2 tasks where competing for the same limited resources of VSS

• Condition 2 - two different stores used (PL & VSS) 

- this supports the limited capacity for VSS

Outline Baddeley, Thompson & Buchanan (1975) research into Phonological Loop.

PROCEDURE:

• Lab experiment, repeated measure

• Participants given visual presentations of word lists vs brief exposure & then asked to recall in serial order 

1) List = 5 mono-syllabic English words e.g. cat, with, twice

2) List = polysyllabic English words e.g. university, organisation 

- measure which condition led to better recall

RESULTS:

• Over several trials participants recalled more short words than long words = word length effect

• Participants able to recall as many words as they could articulate in 1.5 secs

- Longer words can’t be rehearsed because they don’t fit in the articulatory process

CONCLUSION:

• PL capacity determined by the time taken to say words rather that number of items

• Time est. = 1.5 secs

Why is the Central Executive considered vague?

• Little research to support it

• WMM doesn’t explain how or why it directs attention

Outline Bertz (1995) in terms of limitation of WMM.

• WMM fails to consider musical memory so lacks validity

• E.g. Bertz found that participants could listen to instrumental music (w/o words) without impairing performance on doing other acoustic tasks at the same time

What is a practical application of the WMM?

• Aid dementia sufferers (where area of their brain dies)

• They have difficulty doing dual tasks, Baddeley suggests there’s a fault w/ CE (so can’t process a lot of information)

• To help? reduce information or slow down info