WMM

What is the WMM and who was it developed by?

• The working memory model is a model of memory that focuses on the short term/working memory - it is a cognitive system that argues that short term memory is not a unitary store

• It was developed by Baddeley and Hitch (1974)

What are the key features of the WMM and what are their functions?

• Central executive:

  • directs attention, determining how the brain’s ’resources’ are allocated

  • Controls which parts of the model are in use and coordinates all other mental functions in working memory

  • It can process different types of information (modality free)

  • It has a limited capacity and can only pay attention to a small number of things at once

• Phonological loop:

  • Stores a limited number of sounds for short periods of time and preserves the order of information

  • Has a limited capacity - 2 secs worth of info

  • Coding: acoustic

  • Was further subdivided by Baddeley in 1986 into: The phonological store (“inner ear”)

    • Stores acoustically encoded memories (eg. Sounds) for short periods of time

    • Used for words that are heard

  • An articulatory (control) process (“inner voice”)

    • Responsible for subvocal repetition (saying things in your head eg. Counting mentally) - this is a form of maintenance rehearsal

    • Used for words that are heard or seen

• Visuo-spatial sketchpad (“inner eye”)

  • Stores visual and spatial info

  • Codes visual information in terms of separate objects as well as the arrangement of these objects in one’s visual field

  • Holds and manipulates static images eg. Rotate, change colour

  • Has a limited capacity and can only do a number of things at once (but can do things at the same time as the phonological loop)

  • Logie suggested in 1995 that it could be divided into: A visual cache

    • Stores information about visual items eg. Form and colour

  • An inner scribe

    • Stores the arrangement of objects in the visual field

• Episodic buffer (added by Baddeley in 2000)

  • Receives input from many sources, temporarily stores this information, and then integrates it in order to construct a mental episode of what is being experienced

  • Maintains a sense of time sequencing - basically recording events that are happening

  • Links LTM to wider cognitive processes like perception

  • Has a limited capacity of about 4 chunks, but can do things at the same time as the other stores

  • It can process different types of information (modality free)

What are the 2 predictions that the WMM makes?

1. If 2 tasks make use of the same component they cannot be performed successfully

2. If 2 tasks make use of 2 separate components of memory they should be able to be performed successfully

Explain the dual performance experiment that supports the WMM

• The WMM is strong because it is supported by evidence from experiments

• Robbins et al’s (1996) dual performance experiment

• 12 good chess players played 4 games while doing another task simultaneously, each game the players had to do another task involving either: the central executive, the visuo-spatial sketchpad, the phonological loop, or nothing as a control. The findings were that the players performed worse when completing the additional tasks that involved the central executive or the visuo-spatial sketchpad, but not the phonological loop

• It could be argued that this experiment lacks ecological validity

• The task involving the phonological loop didn’t take up any capacity from the visuo-spatial sketchpad so the chess performance was unimpaired, supporting the idea of the existence of separate stores in the STM, thus supporting the WMM

What are the general strengths of the WMM? (SODA)

• Supported by case studies

• Supported by controlled lab experiments - suggests internal validity

• It’s an advance on the MSM because it gives significantly more detail about how memory is processed in the STM and doesn’t rely on verbal rehearsal for transfer of memory (more complex)

• Application: knowledge of memory can help teach brain damaged individuals how to function more effectively, the WMM has useful predictive validity as the WM is a predictor of IQ

Explain how evidence from case studies supports the WMM

• Shallice and Warrington (1970) studied KF. His short term forgetting of auditory information was greater than visual stimuli, and his auditory problems were limited to verbal material, not meaningful sounds (like a phone ringing) - this would suggest that his brain damage is limited to the phonological loop and supports the idea of STM as 2 separate stores

• Trojano and Grossi (1995) studied SC. He had generally good learning abilities with the exception of being unable to learn word pairs that were presented out loud - this also suggests damage to the phonological loop

• Farah et al (1988) studied LH. He had been involved in a road accident, and performed better on spatial tasks than on those involving visual imagery. This supports the idea of separate visual and spatial systems, as suggested by the WMM

• Some individuals with brain damaged suffer from ‘disexecutive syndrome’ which involves problems with planning, organising, and monitoring and initiating behaviour. These patients typically have damage to the ‘frontal lobe’ - this supports the existence of the central executive and suggests that it is located in the frontal lobe

• Stuss and Alexander (2007) studied patients with more specific brain damaged suffer to regions of the frontal lobe and found 3 executive functions based on:

  • Task setting

  • Monitoring

  • Or energisation

  • Thus there may be evidence that there are 3 elements to the central executive

Explain this strength of the WMM: evidence for the phonological loop and articulatory process

• a strength of the WMM lies in the phonological loop and its explanation of the word-length effect - the fact that people can cope better with short words than long words in the working memory (STM)

• It seems to be that the phonological loop holds the amount of information that you can say in 2 seconds (Baddeley et al, 1975) - this makes it hard to remember a list of long words (eg. ‘Association’) compared to shorter words (eg. ‘Harm’)

• The longer words can’t be rehearsed on the phonological loop because they don’t fit

• However, the word length effect disappears if a person is given an articulatory suppression task, eg. Say ‘the the the’ while reading the words. This repetitive task ties up the articulatory process and means you can’t rehearse the short words more quickly than the long words, so the effect disappears

• This is evidence for the articulatory process - a key component of the WMM

Explain the problem with using case studies to evidence the WMM

• brain injury is traumatic, which may in itself change behaviour so that a person performs worse on certain tasks

• Individuals who have suffered serious brain damage may have other difficulties such as difficulties paying attention and therefore underperform on certain tasks

• Case studies are of unique individuals and cannot be generalised to the population

• This is an issue for the WMM as some of the key research that supports it comes from case studies

What evidence is there for the episodic buffer?

• Baddeley added the episodic buffer to account for the fact that many tasks required a general store to process information from the other stores

• Baddeley conducted an experiment in 2009 to test whether participants were better able to recall lists of words or words from sentences

• He found that participants remember many more words in sentences

• He used this to suggest that the episodic buffer was involved in organising this information

What are the general weaknesses of the WMM?

• the model is still oversimplified - senses such as taste, touch, smell are ignored in the model

• Evidence suggest that the four components interact, but it’s unclear how - so the model is still an incomplete explanation

• The model is concerned with memory but almost totally neglects the LTM and on this level the model tells us less than the MSM

• Relatively little is known about the central executive - research by Miyake (et al 2000) and Stuss & Alexander (2007) suggest it is more complex than a unitary store, but the number and nature of functions are unclear

• Problems of using case studies

Explain this criticism of the WMM: there is lack of evidence for the central executive and it may not be a unitary store

• the WMM is a weak model because the concept of a single central executive is too vague and doesn’t explain anything - all it seems to do is allocate resources and essentially be the same as ‘attention’

• Eslinger & Damasio (1985) studied EVR, who had a cerebral tumour removed

• He performed well on tests that require reasoning, which would suggest that his CE was intact, but he had poor decision making skills (he would spend hours deciding what to eat) which would suggest that his CE wasn’t wholly intact

• However, case studies are not generalisable, and the trauma and other disadvantages that come with brain damage may have affected this

• The CE is unsatisfactory because its probably more complex than originally suggested