Memory (Part 2) Working Memory Flashcards
Working Memory (Alan Baddeley)
Baddeley & Hitch (1974) / Baddeley (2000) suggested a different model as an alternative to the classical STM model
They called it “working memory” (WM) to emphasise that information in this store is not passively stored, but actively manipulated (you work with it!)
Working memory is characterised by…
Limited capacity
It can retain information over a period of seconds to minutes
It is possible to perform mental operations on the contents
The focus of the model is on manipulating information
Working Memory
The original model had three components
The phonological loop and the visuospatial sketchpad serve the maintenance of information in WM
The role of the central executive is the control of mental operations
Phonological Loop
The phonological loop utilises sound-based codes for representing information
It uses rehearsal process – similar to the classical model of STM
Its functions are maintenance of all verbal information (or material that can be represented using a verbal code), but also language comprehension and acquisition
Evidence of the Phonological Loop
Baddeley and colleagues (and others) conduced a series of experiments to show that (and how) the phonological loop operates
Phonological similarity effect:
The similarity effect describes the problem that verbally similar items are more difficult to remember because their phonological codes are easy to be mixed up and interfere
Phonological Similarity effect
The similarity effect describes the problem that verbally similar items are more difficult to remember because their phonological codes are easy to be mixed up and interfere
Unattended Speech Effect
Speech-based sounds disrupt performance when trying to remember letters
The reason for that is that speech taps into same resource as rehearsal
This means, the phonological loop is already “occupied” with irrelevant material
Word Length Effect
It is easier to rehearse mono-syllabic words than poly-syllabic words
The reason is that long words take more time for the phonological loop for rehearsal. While one word is rehearsed, the others already decay!
Visuo- spatial sketchpad
It temporarily holds visually based representations in WM
These could be faces, objects, and written words
It is also important to manipulate mental images, handle visual memories, or perform mental rotation
The sketchpad is an independent system from the phonological loop that was not included in STM model
Dual Task Paradigms
These experiments required the performance of a verbal task and a visual task simultaneously
They demonstrated that there was no interference between modalities
Visuo-spatial sketchpad and brain damage
Another approach is to investigate performance of brain damaged patients
Damage to discrete parts of the brain demonstrate a dissociation between both systems
The phonological loop is associated with a left-hemisphere parietal lobe network, while the visuospatial sketchpad is compromised by damage to the right parieto-occipital region
Central Executive
The central executive is a system that controls the operations of working memory, thus the phonological loop and sketchpad
It allocates attentional resources and adjusts goal priorities moment by moment (Jonides, 1995)
The central executive is a capacity-limited attentional system, not memory itself!
It also relates the working memory sub-systems to information from long-term memory
Functions of the Central Executive
The central executive a rather vague concept, because it has a lot of functions. It is related to (or shares functions with) other general high-level control systems and concepts, such as:
cognitive control attention prefrontal / parietal “multi-demand” network the homunculus the self fluid intelligence prospective memory consciousness
Episodic Buffer
Later, Baddeley (2000) included another sub-system to his working memory model: the episodic buffer
He realised that his WM model did not explain the transfer of personal memory well enough
The episodic buffer is conceptualised as a storage system, binding information from a number of sources
It is involved in creating coherent episodes and in the transfer of learning to LTM
