The Working-Memory Model - Memory Psychology

The WMM is a representation of short-term memory, proposed by Baddeley and Hitch (1974). According to the WMM, STM is a processor of different information, using smaller units which are co-ordinated by a central decision making system. 

                                                      

The Central Executive:

·       the ‘controller’ of the whole system

·       it can store information for short periods, but has a limited capacity

·       it is responsible for a wide range of important control processes such as: monitoring/correcting errors, and retrieving information from long-term memory

·       it is located at the pre-frontal cortex

·       it helps the visuospatial sketchpad and the phonological loop if they become overloaded

·       people with damage to this area (the pre-frontal cortex) have problems with planning, organising, monitoring and starting tasks and thus, this is what the central executive is responsible for

THE ‘SLAVE’ SYSTEMS:

1.     The Phonological Loop

·       this is responsible for processing sound-based (verbal) information

·       it is split up into the ‘phonological store’ and the ‘articulatory loop’

·       the phonological store (‘inner ear’) holds auditory memory traces for a few seconds (2) and is concerned with speech perception

·       the articulatory loop (‘inner voice’) is used to prepare speech, and is concerned with speech production – it has a limited capacity

2.     Visuospatial Sketchpad (‘inner eye’)

·       this monitors where we are in relation to other objects as we move around our environment

·       it has a limited capacity and therefore it’s difficult to perform several visuospatial tasks at the same time

·       Logie (1995) sub-divided the VSS into the visual cache (which stores visual data eg. shape and colour of objects) and the inner scribe (which deals with the arrangements of objects in our visual field).

3.     Episodic Buffer

·       this is the 3^rd slave system, which was added in 2000.

·       it is a temporary store for information

·       it integrates the visual, spatial and verbal information processed by other stores, and maintains a sense of time sequencing

·       it is the storage component of the central executive

·       it has a limited capacity of about 4 chunks (Baddeley (2012))

Central Executive - Research

Baddeley (1996) discovered participants found it difficult to generate lists of random numbers while simultaneously switching between pressing numbers and letters on a keyboard – the two tasks are competing for CE resources.  This supports the idea of the CE being limited in capacity and only being able to cope with one type of info at a time.

Phonological Loop – Research

Baddeley et al. (1975) investigated the existence of a phonological loop in STM. Participants saw everyday words displayed very quickly after the other. Condition 1 had a list containing one-syllable worlds and condition 2 had a list containing polysyllabic words. Baddeley found that participants were able to recall the shorter, one-syllable words much better (“word length effect”). Therefore, we can conclude that the phonological loop has a role in the capacity of STM. The amount you can hold is determined by the length of time it takes to say the words – not the number of items.

Visuospatial Sketchpad – Research

Gathercole and Baddeley (1993) - participants had difficulty simultaneously tracking a moving point of light and describing the angles on a hollow letter ‘F’ because both tasks involved using the VSS. Other participants had little difficulty in tracking the light and performing a simultaneous verbal task, as the tasks involve using both the VSS and PL, indicating the VSS to be a separate slave system – as otherwise, both tasks would be equally as difficult to do.

EVALUATION:
P: there is clinical evidence to support this model
E: Shallice and Warrington (1970) had a brain-damaged patient, KF, who had poor STM ability for verbal information – but could process visual information. He also had difficulty with sounds, but could recall letters and digits. This seems to suggest that only his phonological loop was damaged.

E: This supports the idea of separate visual and acoustic stores – however, evidence may not be reliable from patients with brain damage because they are unique case studies and so, they potentially aren’t generalizable to the population.

P: there is a lack of clarity
E:  it is unclear what the central executive is, as it is the least understood component: some psychologists believe it consists of further separate components

E: therefore, the WMM explanation is incomplete and potentially lacks credibility as an explanation because it can’t offer a full explanation of its purpose and function.

P: there is supporting evidence from dual-task studies

E: for example, Gathercole and Baddeley (1993) found that participants had more difficulty completing two tasks that involved using the VSS, compared to using the VSS and the PL – suggesting that they are separate slave systems

E: this provides support for the WMM, and thus increases its credibility

P: there are strengths and weaknesses

E: the model was developed based on evidence from laboratory experiments and so, confounding variables could be carefully controlled to produce reliable results.

E: however, results from laboratory experiments will often have low ecological validity, as the tasks used (such as describing the angles of a letter and repeating ‘the the the’) are not representative of everyday activities.