Define working memory
Working memory is a cognitive system that refers to the process that temporarily stores and manipulates information, so that we can use that information to undergo complex cognitive tasks (e.g. follow a conversation).
What are the components of the WM model?
The latest model has four main components. These are: a modality-free central executive, a phonological loop , a visuospatial sketchpad and an episodic buffer. Each of these components have limited capacities.
Define the phonological loop.
The phonological loop is the component of the working memory in which speech based information is stored and subvocal articulation occurs.
Describe the brain areas associated with the PL
- phon store = left inferior parietal cortex
- Some brain-damaged individual have very poor memory for auditory-verbal material but essentially normal speech production- indicating they have damaged phonological store but an intact articulatory control process. Patients typically have damage to the left-inferior parietal cortex (Vallar & Papagno 1995.)
- artic loop =left-inferior frontal cortex
- other brain damaged patients have an intact phonological store but a damaged articulatory control process shown by a lack of evidence for rehearsal. (left-inferior frontal cortex (vallar & Papagno 1995)
define the visuo spacial sketch pad.
Component of the WM that deals with visual and spatial information
describe the brain areas associated with the VSSP
Brain areas associated with the two components of visual-spatial sketchpad
Zimmer (2008) found areas within the occipital and temporal lobes were activated during visual processing. In contrast areas within the parietal cortex were activated during spatial processing.
describe the Central executive.
This is responsible for monitoring and coordinating the operation of the slave systems (the phonological loop and the visa-spacial sketchpad) and long term memory. The central executive decides what information is attended to and gives priority to certain activities but does not store information per se.
describe the process of the CE
Evidence from behavioural studies (miyake et al, 2000) and neuroimaging studies (Glascher et al, 2012), suggests that the central executive consists of various related but separable executive processes. These include functions of inhibition, shifting and updating (as proposed miyaje, 2000 in her unitary/diversity framework).
what is the episodic buffer?
This is a limited capacity subsystem of the working memory that stores multimodal information (from the phonological loop and the visuo-spacial sketchpad) and serves as an interface between LTM and WM.
How is WM measured?
- Working memory capacity can provide an insight into how much information a person is able to process at the same time and is measured by assessing storage and concurrent processing. For example, Daneman and Carpenters (1980) span test requires participants to read a list of sentences. The participants are required to process them in terms of meaning (the processing load ) and are required to recall the last words in the sentence ( storage)
- Weschler memory scale tests (WMS- III uk) used to assess WM function= digit span, spatial span & letter-number sequencing
How is the PL measured?
- digital-span tasks (the amount of digits you can hold consciously in one moment)
- nonword repetition tasks, such as Gathercoles non-word reputation task( participant asked to repeat a stream of increasingly long words).
How is the VSSP measured?
- Matrix Span (where participants view a grid of black and white squares and then later are asked to recall the position of all the black squares)
- Corsi block test (where the experiment taps a sequence of blocks from an array of nine blocks and the asks the participant to recollect the items) are examples of this .
How is the CE measured?
- Measurements of executive function are less clear cut and there is some dispute over the best ways to measure executive function.
- In clinical settings, the most widely used measures are the Wisconsin card sorting tests and verbal fluency.
- The Wisconsin card sorting test is a neuropsychological test of “set-shifting”, i.e. the ability to display flexibility in the face of changing schedules of reinforcement.
- Verbal fluency measures how quickly people can retrieve category specific information from LTM.
- One of the widely used measures of CE performance in research is the random generation task. This requires subjects to generate a list of items such as digits or letters in a random order without referring to stereotyped response sequences.
What role does the phonological loop have in communication?
- Examining language for logic - Baddeley and lewis (1981) found that articulatory suppression interfered with a subjects ability to detect errors of logic or word order in a sentence, suggesting that the function of the phonological loop may be to hold on to the sentence for long enough to analyse it for logic, word order and overall meaning.
- Learning language - Other studies have suggested that poor WM span affects language, not in terms of comprehension, but in terms of how we learn language.
What role does the visuo-spacial sketch pad have in communication?
- Supports verbal learning via imagery mnemonics
- It also supports our grammatical comprehension for words of spacial position (e.g. above, below, besides). This was found to be an impairment in people with Williams Syndrome ( a condition that affects the VSSP but not the PL).
What role does the central executive have in communication?
Every Time we engage in a complex activity such as reading, talking, understanding, we make considerable use of the CE. The CE enables us to:
- Selectively attend to relevant information = Allows us to selectively attend to conversation and filter out irrelevant information (Repovs & baddeley 2006) very important for communication!!!! This stops us being distracted from non-salient cues and take in, store and manipulate the relevant information (necessary for comprehension).
- Shift our attention when needed - this is important so that we can shift our attention to different topics in conversation, or when somebody else has their conversational turn, when we have to attend to something else.)
- Planning - coherence in conversation, cohesion in conversations, building narratives with language, developing arguments and structure
- Monitoring function - Monitor sentence for complex syntactical, monitoring it for pragmatic relevance, deleting non-relevant cues
- Coordinate information from LTM to provide context to language (by way of the episodic buffer) - this is useful for so many aspects of language use, comprehension and acquisition. For example, bringing in relevant knowledge to understand the context of conversation,using procedural memory to coordinate articulatory processes, understanding figurative language
- Updating function - Helps us keep up with language and process it at an appropriate speed.
What role does the episodic buffer have in communication?
- Provides the glue to integrate info in the working memory.
- Takes information from LTM (e.g knowledge of language)and binds it to information being received in working memory store.
- Seen by Rudner & Ronnberg (2008) to play a role in language when the signal is diminshed.
What year did Baddeley and Hitch first propose WM model?
1974
What were the assumptions made in the model by Atkinson and Shiffrin (1968)
- Information came in from the environment in a temporary ‘sensory store’
- It was then attended to and went to STM ( sort of working memory)
- Then was transferred into LTM
what were the problems with Atkinson and Shiffrin’s model?
- They assumed that merely holding information in STM guaranteed transfer to LTM - this was disproved by Craik and Lockhart, 1972 with levels of processing model. They found that levels of retention could be altered in LTM depending on what you do with it in WM
- A case study reported by Shallice and Warington (1974) that brain-damaged patient KF could recall verbal but not visual information immediately after its presentation, which supports the WMM’s claim that separate short-term stores manage short-term phonological and visual memories. This suggested that there were different processors for different modalities
What is the word length effect
The suggestion that the memory capacity for the phonological loop is determined by temporal duration of a word.
What are the subcomponents of the PL?
- It has a passive phonological store (inner ear) which is concerned with speech perception and holds information in speech-based form from 1-2 seconds,
- articulatory loop (inner voice) which is concerned with speech production. It circulates round and round like a tape loop and helps us to remember words by rehearsal, so that we can prevent words in the phonological store from decaying. The articulatory control also converts written material into an articulatory code and transfers it to the phonological store.
what is the evidence for the PL?
Evidence for the phonological loop - there have been a number of experiments that support the model proposed by Baddeley of the phonological loop.. These include:
- The phonological similarity effect (supports the ‘phonological nature of the store’)- The phonological similarity effect, supports the ‘phonological’ nature of the store and is based on evidence that suggests individuals are worse at recalling words that are phonologically similar. In contrast, words that have semantic similarities have comparatively little effect on recall (Laresen et al, 2000)
- The effect of articulatory suppression (supports the articulatory loop) - Evidence for the existence of the articulatory loop comes from the effects of articulatory suppression. It was found that memory for verbal material was impaired when people were asked to say something irrelevant aloud. It was suggested that this blocked the articulatory rehearsal process, thereby leaving memory traces in the phonological loop to decay.
- Transfer between codes (supports the conversion of orthographic to phonological material) - The idea that orthographic material is transferred into phonological codes in the WM is supported by the idea that adults usually name visually presented material and rehearse it by subvocal articulation. Once again, articulatory suppression prevents this transfer, and in the case of the above mentioned effect of phonological similarity is erased for visually presented items.
- Neuropsychological evidence - Some brain-damaged individual have very poor memory for auditory-verbal material but essentially normal speech production- indicating they have damaged phonological store but an intact articulatory control process. Patients typically have damage to the left-inferior parietal cortex (Vallar & Papagno 1995). Other brain damaged patients have an intact phonological store but a damaged articulatory control process shown by a lack of evidence for rehearsal. (left-inferior frontal cortex (vallar & Papagno 1995)
What are the proposed subcomponents of the visuospacial sketchpad? and who put this forward?
- visual cache - stores info about words and colour
- the inner scribe - processes spacial movement
logie 1995
