Working memory model

What is the working memory model?

• Baddeley and Hitch’s working memory model (WM) replaced the idea of a uniatry STM. It believes STM is more active and complex than the MSM suggested.

• For example, they believed the STM can complete two different tasks at the same time. WM is made up of four interconnected and interactive components.

The central executive

• This is the main part of the working memory model that contains other slave components and decides which component is required for the task

• It is involved in higher mental processes such as descion making and resoning

• It can process information from different senses and each is coded differently

• CE handles more than one task at once

• Allocates resources to the slave components by deciding which is the most important and should be handled first

• CE decides what the WM should pay attention to

• CE has little to no capacity

• Practice tasks become automated thus requires less capacity (fewer attentional demand) of the CE which frees us to perform other tasks

The phonological loops

• The phonological loop codes information acoustically (such as noises and words) it has TWO PARTS:

• Primary Acoustic Store (PAS) - is linked to speech perception

  • codes info acoustically

  • Linked to speech perception

  • The short term store that receives acoustic information - holds for approximately 1-2 seconds

  • Remembers sounds in the same order they were presented

• Articulatory Process (AP)

  • Used to rehearse and store sounds collected by the PAS

  • Capacity - 2 seconds of speech

  • Info from PAS is repeated in the loop to prevent decay (e.g. repeat telephone number)

  • LINKED TO SPEECH PRODUCTION

The Visio spatial sketchpad (VSSP)

• Codes and rehearsed information through visualising mental pictures

• Limited capacity of 3-4 objects

• Logie (1995) subdivided VSSP into

  • Visual Cache - stores visual info about form + colour

  • Inner scribe - handles spatial relations (e.g. follow a mental map also rehearse and transport info in the visual cache to the central executive

The episodic buffer (added in 2000)

• Takes information for VSSP and PL and integrates them together

• Helps with tasks that require both slave systems (e.g. following directions from a satnav verbal instructions -PL

• And from visual maps - VSSP)

• There’s a temporal storage system

• Limited capacity of 4 chunks of information

• Has links to LTM - in case this info is needed by working memory

• Has a two way communication with the LTM

Strength of WMM: Research support from dual task studies

• A strength of the working memory model is that theres supporting research from dual task studies.

• Baddeley and Hitch found that participants could do different  tasks that take up capacity in different stores (e.g. visual and verbal) 

• When partcipants were asked to complete a verbal task in the articulatory loop and a seperate task in the central executive, recall is nor affected

• However, when the same participants were asked to complete two similar tasks (e.g. both tasks in the articulatory loop) then recall in the first task is affected 

• This is a strength as it demonstrates that the short term memory consists of multiple seperate stores each with limited capacity 

• This is shown as participants easily complete tasks that work on different slave systems which means its not overloading the capacity

• However, preforming two similar tasks activate the same slave system

• Meaning that recall on the first task is affected becasue the slave systems was overloaded menaing it is not able to deal with two similar tasks simultaneously

• This increases the validity of the working memory model 

Strength of WMM: Physiological evidence of different components specialising in particular tasks

• A strength of the WMM is that there is research from PET scans to study different components of memory.

• Cohen et al found that the activity in Broca’s area (which is linked to speech production) increasses when participants were completing a verbal task ( reading out loud), whereas reigions of the occipital lobe (which is linked to visual processing) are activated when participants complete a visual task

• This is a strength because it provides physical evidence for existence of the phonological and visual spatial sketchpad

• For example the phonological loops role in auditory and speech based tasks whereas the VSSP’s role is in visual tasks.

• Thus this therefore increaes the validity of the WMM

Limitation: evidence against the unitary view of the central executive 

• A weakness of the working memory model is that there is research to criticise the view that the central executive is unitary 

• The case study EVR had a tumour removed. EVR preformed well on tests which required reasoning which suggested his central executive was intact. However, he had poop decision making skills (e.g. it would take him hours to decide where to eat)

• This is a weakness because the CE is in involved in higher mental processes i.e. reason and descion making if CE was a single unitary store, higher mental processes should be completely normal or completely damaged 

• However, care of EVR shows that some processes of the CE can remain intact while others are damaged 

• This shows that theres several components to the CE which handles different types of human behaviour 

• However the WMM suggests that the CE is unitary 

• This decreases the validity of the WMM

Limitation: The WMM does not account for all types of memory

• One weakness of the working memory model is that the WMM does not account for all types of memory

• Berz (1995) found participants were able to listen to intstrumental music without impairing preformance on other acoustic tasks

• This is a weakness because participants are able to carry out the instrumental music tasks along with the acoustic tasks

• This indicates there may be a ‘musical memory’ component with its own independent capacity, which deals with the instrument music task to prevent overload of the PAS capacity

• This therefore shows that the WMM is incomplete as it fails to account for all types of memory i.e. musical

• This decreases the validity of the WMM

Differences between the MSM and WMM

• Processing info in MSM is passive

• Whereas in WMM it is active

• STM in MSM is one component

• STM in WMM is a multi-component structure

• Information in the MSM passes in a fixed linear order

• Whereas there is interchange between componenets of WMM and no fixed order

• Encoding in the STM in the MSM is acoustic

• Whereas encoding in the STM in the WMM is acoustic and visual