Transcript Short Term Memory

Atkinson and Shiffrin –
Multi store Model of
Memory
1960’s
Memory storage in three separate
but interacting systems
External
Stimulus
Internal
Stimulus
Maintenance Rehearsal
Sensory
Register
Short term
Memory Store
Long term
Memory Store
Response
Forgetting
Forgetting
Forgetting
Sensory Register
 Refers to information detected by the sensory
receptors which is retained temporarily in the
sensory register
 Only able to momentarily hold accurate images
 Images are held long enough for relevant
details to be attended to and transferred to STM
 Info that isn’t attended to – the memory trace
decays & disappears
 Function – to briefly hold sensory information
There is a possibility that information
may bypass the Short –Term Store &
go directly to the Long-Term Store,
but Atkinson & Shiffrin didn't explain
how or why this may occur.
Structural Features
(of Atkinson Shiffrin Model)
Permanent, built in, fixed features of memory
- 3 different memory stores
- Storage capacity of each store
- Function of each store
- Duration each can hold information
 Likened to the hard drive of the computer
Control Processes
(of Atkinson Shiffrin Model)
Conscious control by the individual
- Attention to incoming info
- Rehearsal of information
- Retrieval Strategy used
 Likened to the person using the computer
Limitations of the
Atkinson-Shiffrin model
 Refer to Pgs 294-5 of your text.
 What are the three main limitations
of the Atkinson-Shiffrin model? Give
a example or how each is now
believed to be different.
Divisions of Sensory
Memory
Iconic
 Visual
 Briefly held 0.3sec
 Very large capacity
 No additional
processing
 Limited by individuals
field of vision
Echoic
 Auditory
 Briefly held
3-4sec
 Very large capacity
 No additional processing
 Limited by individuals
range of hearing
 What? When watching
TV processing delay
Loss of Sensory
Information
 Caused by both interference and decay
 Is faster when stimulus is quickly followed by
another
 Information not passed to STM
To store information in STM
 We must focus our attention on a stimulus or
mental event, thereby shutting out competing
stimuli
Attention
Input
Sensory
Register
Selective Attention filters
information to pass into
STM for processing
Short-term
Memory
Information that is
not attended to is
lost
(Pseudoforgetting)
Short Term Memory
Also known as Working Memory
Allows you to manipulate information contained
in the Sensory or LTM
Very susceptible to interruption or interference
Small amounts of information can be processed
Short-term Memory
Capacity
approx. 7+ 2 bits of info (Miller 1956)
This can be expanded by “chunking” info into larger units
Duration
Approx. 18 – 20 sec (Peterson et al, 1959)
See p304 for explanation.
Processing
To hold info in STM, often encoded verbally, other
strategies, such as visualisation, may be used, making it
possible to “rehearse’ the info.
Digit-span test
 A measure of attention and short-term
memory which tests the recall of a series
of digits
 7 + 2 chunks
Rehearsal
 Is a process that enables info to be held in STM for a
long period of time
 Info can be copied from STM to LTM during rehearsal
 2 types
1. Maintenance rehearsal
 Is the overt or covert repetition of information
 Fine for retaining info in STM but will not always lead to
LTM
2. Elaboration rehearsal
 Info is actively analysed for its physical, sensory or
semantic (meaning features
Input
Rehearsal
Sensory
Register
Information that is displaced
through distraction is lost
Rehearsal is required to
process information in STM
Short-term
Memory
 Remember the number
0011441523329197
0011
44
1523
329197
Chunking
 One way to increase the storage capacity
of STM
 Grouping of single units of info into
higher order units
Consolidation Theory
 Information is gradually and only under
certain circumstances transferred from STM
to LTM
 This takes place after rehearsal
 Physical changes to the neurons in the brain
Consolidation Theory
cont’
 Hebb (1949)
 Assumes that processing continues after
rehearsal and ends if interrupted and the
memory trace will be lost
 Information being remembered is vulnerable
for about 30 minutes
 If processing interrupted then consolidation
does not occur
 if consolidation is prevented, the material
can never be recalled
Processing Information
into
Long-Term Memory
Input
Encoding
Information that is not
encoded properly is lost
Sensory
Register
Short-term
Memory
Successful encoding
transfers information into
LTM
Retrieval of information
enhances elaboration
Long-term
Memory
Input
Consolidation
If consolidation is disrupted,
Information can be lost
Sensory
Register
Short-term
Memory
Memory stabilises
(consolidates) over time
Long-term
Memory
Baddeley & Hitch(1974)
 STM provides temporary storage for the
manipulation of the information
necessary for complex tasks
 Language comprehension
 Learning
 Reasoning
 Problem solving
 Information can come from Sensory
Memory or LTM
 Divided into 3 sub-components
Sensory
Register
Iconic
Memory
Echoic
Memory
Central
Visuo-spatial
Sketch Pad
Executive
Long-Term Memory
Phonological
Loop
Central Executive
 Most important . “Executive supervisor”
 Very active
 Responsible for selection, initiation and
termination of processing
 Multi-tasking
 Integrates information from the other 2
subsystems with information retrieved
from LTM
Visuospatial Sketchpad
 Temporary storage and manipulation of
visual and spatial information
Phonological Loop
(articulatory loop)
 Responsible for storing sound / speech
based info
 Stores a limited number of sounds for a
limited period of time
Episodic Buffer
 In 2000, Baddeley decided that the model didn’t
explain how working memory linked with LTM
 He added a fourth component - Episodic Buffer
 This is assumed to be a limited capacity system
that enables the different components of
working memory to interact with the LTM and
holds info:
- Temporarily
- In any form
- About 4 chunks
Episodic Buffer
 Baddeley (2000)
Central Executive
VisuoSpatial
Sketchpad
Visual
Semantics
Episodic
Buffer
Episodic
LTM
Phonological
Loop
Language
 Refer to Pg 319 of your text
 What do the words “episodic” & “buffer”
refer to?
Craik & Lockhart’s “Levels
of Processing” Framework
 Craig & Lockhart argued against the
theories that centred around memory
having different storage systems that
memories flow through
 Their theory stresses the depth or level
that new information is processed at.
Craik & Lockhart’s “Levels of
Processing” Framework cont’
 C & L believed that the way we process
information will impact our LTM of that
information
 Semantic Encoding: The information is
process according to meaning.
 There is a continuum of encoding:
 Shallow: Info retained only briefly
 Deeper: Info retained longer
Craik & Lockhart’s “Levels of
Processing” Framework cont’
 Shallow Processing: Viewing the stimulus in a
superficial way / looking at only superficial
visual details.
 Eg Remembering words. Does it have an ‘i’ in
it?
Craik & Lockhart’s “Levels of
Processing” Framework cont’
 Medium Processing: Attending to the acoustic
details of the word. Saying it out aloud.
 Eg What does the word rhyme with?
Craik & Lockhart’s “Levels of
Processing” Framework cont’
 Deep Processing: Attending to the personal
meaning of the word. Does it apply to you?
 Eg Does the word describe me?
Craik & Lockhart’s “Levels of
Processing” Framework cont’
 (Insert pic of graph of levels of
processing)
Craik & Lockhart’s “Levels of
Processing” Framework cont’
Criticism of the Craig & Lockhart Theory
- Level or depth is difficult to measure
Look at
this
picture
for 30
seconds
 1. What is the colour of the girls dress?
 2. Where are the girls arms?
 3. Is the cat looking to it’s right or it’s left?
 4. How may red flower ‘spikes’ are there?
 5. What is the colour of the girls hair?
 6. How many stripes are there on the bottom
of the girls dress?
Eidetic Memory
Also known as “photographic
memory”.
Ability to recall an exact visual image
that persists over time – days / weeks.
Happens most in childhood, less as
teenagers, rarely as adults.