Memory ‘architecture’
Architecture refers to structures –> stagnant
Short term memory store, long term memory
Memory ‘processes’
Processes are the activities occurring within the memory system –> dynamic
What does the original multistore model of memory emphasise?
Emphasises the structures / ‘memory stores’
Describe the original multistore model of memory
Sensory stores
- hold fleeting memory (echoic, iconic) / information in its original sensory modality (visual, auditory)
Short-term memory (STM) store:
- very limited capacity (7 +/- 2)
- storage is fragile
Long-term memory (LTM) store:
- essentially unlimited capacity
- holds information over long periods of time
The mechanisms of forgetting in each store were:
- Sensory –> decay
- STM –> displacement
- LTM –> interference
The links were
Sensory (attention) STM (rehearsal) LTM
What are the 3 criticisms of the original multistore model
- STM and LTM store are not unitary (independent functions that operate independently) - instead they have subcomponents (i.e. the STM replaced by working memory, the LTM replaced by episodic and semantic memory)
- Over-emphasis of structural aspects (assumed static stores)
- Assumed that STM is a gateway to LTM –> but we know from ‘chunking’ that LTM can inform STM tasks, and also that rehearsal may not be crucial to learning and that impairment of STM does not necessarily lead to impairment of LTM (patient kf)
Discuss Patient KF and his relevance
Patient KF demonstrates that the impairment of STM does not necessarily lead to the impairment of LTM.
Injury = left parieto-occipital fracture
Deficit: inability to repeat verbal material
Retained: ability to pair-associate learning (baby-cry) - i.e. intact LTM
Describe Baddeley & Hitch’s Working Memory Model
Central executive (a modality free attention system which coordinates the peripheral store) links multi-directionally to these three components via rehearsal:
- Phonological loop (inner voice): holds information in speech-based form
- Episodic buffer: holds and integrates diverse information
Idea that each component is independent of eachother –> if two tasks using the same component are done together, they will be done poorly, whereas if two tasks using two different components are done together, they will be successful.
- Visuo-spatial sketchpad (inner eye): specialised for spatial and/or visual coding
Describe the phonological loop system
Phonological loop is for verbal/speech-based memory
Passive Store:
- holds verbal information
- auditory presentation of words has direct access
- visual presentation has indirect access (via articulatory control)
Articulatory control process:
- like subvocal speech
- maintains phonological information through rehearsal
- provides access to store for visual input
What is the evidence for the phonological loop:
- phonological similarity effect: immediate serial recall of verbal material is reduced for visually presented lists of items that sound similar (indicates use of articulatory control process) –> articulatory suppression eliminates the phonological similarity effect for visually presented stimuli but not auditorily (spoken) stimuli
- word length effect: memory span is reduced for longer words (the articulatory duration is responsible for hte word length effect)
What is the phonological loop for?
- used in temporary storage and manipulation of phonological (speech) information
- involved in learning new word forms (new language and sounds)
Patient PV:
- impairment to digit span made them unable to learn Russian words (even when paired with native language)
In native italian speakers, articulatory suppression disrupted foreign-native word pairings, but not native-native word pairings.
Describe the Visuo-spatial sketchpad
Inner eye - visual equivalent of the phonological loop which is specialised for spatial / visual coding
Consists of two components:
- Visual cache: stores information about visual form and colour
- inner scribe: processes spatial and movement information, involved in rehearsal of info in visual cache, transfers info form the cache to the central executive
Describe the episodic buffer
Later contribution to the working memory model because the components were too separate in their functioning
Provides temporary storage for integrated information coming form visuo-spatial sketchpad and phonological loop
Process of active binding: an example is visuo-spatial bootstrapping of verbal memory
- immediate serial recall of a sequency of random digits is better when presented on a keypad display than a single item
Describe the central executive
Keeps the goal of the task in mind and instructs the slave systems.
Example = the stroop task - conflict between naming ink colour and naming text
There are two forms of attentional control
- contention scheduling (schema hierarchy)
- supervisory attentional system (central executive - fully conscious control and flexible - located in prefrontal cortex)
What are the differences between working memory tasks and short term memory tasks
STM: usually domain specific (digit span for phonological loop)
Working memory: trying to maintain information in active memory while simultaneously performing distracting activities (operation span task)
