Memory Flashcards
Describe short-term memory (STM)
-acoustically coded
-limited capacity of approx 5-9 items
-duration of approx 18-30s
Describe long-term memory (LTM)
-semantically coded
-unlimited capacity, permanent store
-duration up to a lifetime
What is coding?
The format in which information is stored in various memory stores
Who did research on coding and when?
Baddeley 1966
Describe the procedure and findings of Baddeley’s research into coding
Gave different lists of words to 4 groups
1. acoustically similar
2. acoustically dissimilar
3. semantically similar
4. semantically dissimilar
Asked to recall the words in order
immediate recall (STM) was worse when acoustically similar- STM coded acoustically
after 20 minutes (LTM) recall was worse when semantically similar- LTM coded semantically
What is a strength and a weakness of Baddeley’s research into coding?
Identified clear difference between stores
-STM mostly acoustic
-LTM mostly semantic
-stood test of time
Helped understanding of memory leading to the MSM
Lacks mundane realism
-artificial stimuli with no personal meaning
-doesn’t say anything about memory in real life
-more meaningful STM may be coded semantically
Limited application
What is capacity?
The amount of information that can be held in a memory store
Who did research on capacity and when?
Jacobs 1887
Miller 1956
Describe the procedure and findings of Jacobs’ research into capacity
Researcher read out digits, adding one each time until the participant repeats it back in the incorrect order
Digit span for digits is 9.3 but 7.3 for letters as a mean
Describe Miller’s research into capacity
Found that things come in 7s (eg: days of the week, musical notes)
STM capacity is 7±2
Can also recall 5 words as easily as 5 letters via chunking
What is chunking?
Grouping sets of digits/letters into units/chunks
What is a strength and a weakness of research into capacity?
Jacobs’ research replicated
-although at time lacked adequate control over EVs and CVs
-so digit span may have been underestimated due to distraction
-but results confirmed by a controlled study by Bopp and Verhaeghen
Valid
Miller may have overestimated the STM capacity
-Cowan 2001 replicated concluding 4±1 chunks
Lower end of Miller’s estimation is more appropriate
What is duration?
The length of time information can be held in memory
Who did research on duration and when?
Peterson and Peterson 1959
Bahrick et al 1975
Describe the procedure and findings of Peterson and Peterson’s research into duration
24 students each in 8 trials with different retention intervals (3, 6, 9, 12, 15, 18)
In each trial they were given a consonantal trigram, and then had to count backwards from a 3-digit number to prevent mental rehearsal
After 3s, recall 80% accurate
But after 18s, recall 3% accurate
STM duration is 18s unless verbal rehersed
Describe the procedure and findings of Bahrick et al’s research into duration
392 Americans had their high school yearbooks obtained
Tested for photo recognition and free recall
Within 15y of graduation, photo recognition 90% accurate, but 70% after 48+y
Within 15y of graduation, free recall 60% accurate, but 30% after 48+y
Shows LTM may last up to a lifetime for some material
What is a strength and a weakness of research into duration?
Bahrick et al’s research has high external validity
-measures meaningful memories
-recall is lower for meaningless memories, shown by Shepard
Reflects more real estimate of LTM duration
Peterson and Peterson use artificial stimulus
-doesn’t reflect everyday memory activities with meaningful material
Lacks external validity
Who created the multi-store model of memory and when?
Atkinson and Shiffrin 1968
What is the multi-store model of memory?
3 unitary memory stores where information is transferred between them in a linear sequence to possibly become a memory
Describe the sequence of the multi-store model of memory?
Stimulus from environment –> sensory register –> STM —> LTM
What is on the arrow from the sensory register to the STM in the MSM?
Attention
What is on the arrow within the STM and to the LTM in the MSM?
STM- maintenance rehearsal
STM->LTM- prolonged rehearsal
What is on the arrow from the LSM to the STM in the MSM?
Retrieval
What is the arrow pointing downwards from the sensory register in the MSM?
Decay
What is the arrow pointing downwards from the STM in the MSM?
Response (remembering)
What is the sensory register (MSM)?
Where all stimuli from the environment goes
What is the coding of the sensory register (MSM)?
Modality specific
eg: iconic=visual echoic=auditory
What is the capacity of the sensory register (MSM)?
Very high
For example, one eye has over 100mil cells storing data
What is the duration of the sensory register (MSM)?
Very brief- less than half a second
Describe how information transfers between the STM and LTM in the MSM
Through maintenance rehearsal, material is repeated over and over, if if this is done for long enough (prolonged rehearsal) it passes to the LTM
To retrieve information, it’s transferred back to the STM
Describe the case of patient HM
His hippocampus was removed
He performed well on STM tasks
But remembered little personal/public events and his LTM never improved
Shows the stores are seperate
Describe the case of patient KF
He had amnesia
When read aloud, his digit span was poor
But when he read it himself, his recall was better
Shows separate STM stores for visual/auditory information
What is the strength of the multi-store model of memory?
A lot of research support
-HM shows that memory is made up of separate stores for different types of memory
-Baddeley showed STM mixed up when acoustic and LTM mixed up when semantic, shows they’re independent stores
The explanatory power of the MSM is increased
What are 2 weaknesses of the multi-store model of memory?
Oversimplifies memory, more than 1 STM store
-patient KF shows separate for visual/auditory
Unitary theory is questioned, reducing credibility
Other types of rehearsal needed to transfer information to the LTM
-Craik and Watson 1973 also found elaborative rehearsal, linking to existing knowledge needed to transfer
MSM can’t fully explain transfer to LTM, explanatory power reduced
Who created the working memory model and when?
Baddeley and Hitch 1974
What are the 4 components of the WMM?
Central executive
Visuo-spacial sketchpad
Phonological loop
Episodic buffer
In the WMM- the central executive…
1. What does it do?
2. What is its coding?
3. What is its capacity?
Monitors incoming data
Divides/focuses attention, allocating tasks to the 3 slave systems
Coding- can’t store information, but processes any modality
Capacity- very limited
In the WMM- the phonological loop…
1. What does it do?
2. What is its coding?
3. What is its capacity?
Processes auditory information (spoken/written) preserving the order
Made up of the phonological store (stores words heard) and the articulatory process (allows maintenance rehearsal)
Coding- acoustic
Capacity- 2 seconds
In the WMM- the visuo-spatial sketchpad…
1. What does it do?
2. What is its coding?
3. What is its capacity?
Processes visual and spacial information in the inner eye
Logie 1995 further divided to visual cache (visual info) and inner scribe (spacial info)
Coding- visual
Capacity- 3-4 objects
In the WMM- the episodic buffer…
1. What does it do?
2. What is its coding?
3. What is its capacity?
Added in 2000, temporary store for information processed by other stores
Maintains time sequencing
Links the WM to the LTM and wider cognitive processes
Coding: store for the central executive, modality free
Capacity- about 4 chunks
What are 2 strengths of the working-memory model?
Clinical evidence
-Patient KF, phonological loop damaged, visuo-spatial intact
Supports evidence of separate visual/acoustic stores
Dual-task performance supports
-Baddeley had participants do visual/verbal task at the same time with similar performance
-When both tasks the same, performance decreased due to competition, no competition in first task
Must be separate subsystems
What are 3 weaknesses of the working-memory model?
Clinical evidence…
-may have other cognitive impairments, KF in a motorbike accident caused trauma
Can’t generalise findings to other people
Dual-task performance…
-tasks lack mundane realism, high control in lab, not like real life
Can’t generalise findings to real-life situations
Lack of clarity over the nature of the central executive
-‘most important but least understood
-must be more than attention, may be subcomponents
WMM not fully explained, integrity decreased
Who created the theory about the 3 types of long-term memory and when?
Tulving 1985
What are the 3 types of LTM?
Episodic (like a diary)
Semantic (like a dictionary or an encyclopaedia)
Procedural