Memory L1 - 4 Flashcards
Duration:
Measure of how long info can be stored for
To keep info in STM for more than a few secs, what do humans do?
Rehearse the info
Which study supports the duration of STM?
Peterson and Peterson (1959)
Procedure of Peterson and Peterson (1959) study:
1) 24 undergrads presented w/ consonant trigram
2) Asked to count backwards in threes from random digit number to prevent rehearsal of trigram
3) After intervals of 3, 6, 9, 12, 15, 18 secs, participants had to repeat trigram
Results of Peterson and Peterson (1959) study:
- After 3 secs, 90% of trigrams could be remembered
- After 9 secs, 20%
- After 18 secs, less than 10%
Conclusion of Peterson and Peterson (1959) study:
- Info decays quickly when it can’t be rehearsed
- Max STM duration is 18-30 secs w/out rehearsal
Strengths and weaknesses of Peterson and Peterson (1959) study:
+ Variables are tightly controlled so study can be replicated
- Low ecological validity as trigrams are unrealistic (lacks mundane realism)
- Lacks pop validity (only undergrads)
- Was forgetting due to confusion from trigrams presented earlier (interference) or actual forgetting?
Which study supports the duration of LTM?
Bahrick et al (1975)
Procedure of Bahrick et al (1975) study:
Tested how well American pps between ages 17 and 74 could remember former classmates by identifying pics, matching names to pics and recalling names w/ no pic cue
Results of Bahrick et al (1975) study:
Even after 48 yrs:
- Linking names to pics –> 70% accuracy
- Free recall –> 30% accuracy
Conclusion of Bahrick et al (1975) study:
- Long term memory can last a lifetime
- Individuals cannot access LTM memories immediately, but recall is much higher when presented w/ cues
Strengths and weaknesses of Bahrick et al (1975) study:
+ High external validity as meaningful material was investigated
- Less control of IV as it is a natural experiment so there is a possibility names may have been rehearsed (confounding variable)
- Looks at very specific type of info (meaningful + regularly rehearsed)
In conclusion, what is the duration of STM and LTM?
Duration of STM: 18-30 secs
Duration of LTM: Lifetime
Which study supports the capacity of STM?
Jacobs (1887)
Procedure of Jacobs (1887) study:
Developed digit span technique
1) Researcher read out 4 digits and asked to repeat it back immediately
2) More digits added until pp could not repeat it accurately
Results of Jacobs (1887) study and reasoning:
- On average, 9 digits and 7 letters recalled
- Capacity increased with age during childhood (avg digit span for 8 yr olds was 6) due to gradual increase in brain capacity/strategies developed eg. chunking
- Digits may be easier to recall because there are only 10 to remember compared to 26 letters in alphabet
Strengths and weaknesses of Jacobs (1887) study:
+ Has been repeated since w/ same results so it is valid
- Lacks ecological validity as repeating random lists of numbers is not realistic as more meaningful info may be recalled better
-Previous sequences recalled may have confused the pp
-Cannot be sure whether EVs were controlled as it was conducted long ago (lacks temporal validity)
Which study reviewed the capacity of STM and what did it conclude?
- Miller (1956)
- Capacity of 7±2 items
- Memory capacity can be increased through chunking eg. Ppl can remember 5 letters as well as 5 words
What is one evaluation of Miller’s (1956) study?
- Size of chunk matters
- Cowan (2001) reviewed research and argued Miller may have overestimated the capacity of STM
- Concluded capacity was about 4 chunks
Coding:
Form in which info can be stored in the various memories
What are the 3 ways of coding?
- Acoustic –> storing info in terms of way it sounds
- Semantic –> coding info in terms of meaning
- Visual –> storing info in terms of the way it looks
Which study supports the coding of STM and LTM?
Baddeley (1966)
Procedure of Baddeley (1966) study:
Participant shown sequence of 5 words under these 4 conditions + immediately/after 20 mins write them down in order
1) Acoustically similar
2) Acoustically dissimilar
3) Semantically similar
4) Semantically dissimilar
Results of Baddeley (1966) study:
- Tested immediately –> least accurate w/ acoustically similar words
- Tested after 20 mins –> least accurate w/ semantically similar words
Conclusion of Baddeley (1966) study:
- Info is normally encoded acoustically in STM
- Info is normally encoded semantically in LTM
- Info can also be stored in other forms eg. visual
Strengths and weaknesses of Baddeley (1966) study:
+ Identifies clear difference in coding of two memory stores
- Low ecological validity as list was meaningless (lack of mundane realism)
Who proposed the multi-store model, what does it argue and how can it be described?
- Atkinson and Shiffrin (1968)
- Memory involves flow of info through a series of stages in a fixed linear sequence
- Described as an information processing model (w/input, process and output)
What are the 3 unitary stores of the model?
1) Sensory register
2) STM
3) LTM
Explain MSM:
1) Info is detected by sense organs and enters sensory register
2) If attention is paid, info enters STM, which can be recalled directly. If not, info is lost through displacement
3) If prolonged rehearsal occurs (maintenance proposed by Atkinson + Shiffrin, elaborative proposed by Raaijmakers + Shiffrin (2003)), info enters LTM. Up until this point there is a rehearsal loop w/in STM.
4) Info must be transferred back into STM to be retrieved from LTM
Maintenance rehearsal:
Mental repetition of material
Elaborative rehearsal:
- Material is given some kind of meaning
- More advanced type of rehearsal
Describe the coding for the sensory register
Modality specific. It can be:
- Haptic (touch)
- Ionic (visual)
- Echoic (auditory)
- Gustatory (taste)
- Olfactory (smell)
What does the sensory register do?
Stores sensory info from environment in a short period of time
Describe the capacity and duration of sensory register
Duration: 250 ms
Capacity: Unlimited
Which study supports the sensory register?
Sperling (1960)
Procedure of Sperling (1960) study:
Lab experiment:
1) Pps shown grid w/ 3 rows of 4 letters for 50ms
2) Immediately recall whole grid/randomly chosen row indicated by a tone (high, medium, low) played straight after grid was shown
Results of Sperling (1960) study:
When recalling a particular row, on average, 3/4 items could be recalled regardless of which row
Conclusion of Sperling (1960) study:
- Capacity is very large, as pp could recall any row despite not knowing which to remember, showing the whole grid was in their sensory register
- Duration is very short
Strengths and weaknesses of Sperling (1960) study:
+ Easy to replicate as variables are highly controlled
- Lacks ecological validity and mundane realism
Briefly state the strengths and weaknesses of MSM:
- Explains primacy and recency effect
- Case studies support the fact that STM and LTM are separate
- Brain scanning techniques also support this
- Does not explain flashbulb memories –> idea that all info needs to be rehearsed is an over simplification
- Conflicting evidence of separate stores
- Most studies supporting MSM lack ecological validity
Primacy effect:
More likely to remember the words at the beginning of the list as there is enough time to rehearse them, which increases the likelihood of it moving it into the LTM
Recency effect:
More likely to remember words at the end of the list as they are still held in STM
Which study supports the primacy and recency effect?
Murdoch’s study
Procedure of Murdoch’s study:
Pps asked to free recall lists of words ranging from 10-40
Results of Murdoch’s study and reasoning:
Serial position effect = Pps remembered words depending on their position in the list
Asymptote:
Words in the middle that are too long to be held in STM due to displacement and not long enough to be held in LTM
How does MSM explain primacy and recency effect?
When this info is remembered, pps are recalling them from 2 separate stores
Explain the case study supporting MSM:
- H.M studied by Scoville and Milner (1957)
- Brain damage caused by removal of hippocampus from both sides of brain to reduce severe epilepsy
- STM still intact (could recall list of 6 numbers), however LTMs could no longer be formed
- Therefore, must be 2 separate stores
How have brain scanning techniques supported MSM (w/evaluation)?
- Beardsley (1977) used brain scanning and found prefrontal cortex needed for STM but not LTM tasks
- Squire et al (1992) found hippocampus was active when LTM was engaged
- Therefore STM and LTM must be separate
- However, research suggests hippocampus may be responsible for transferring STM info to LTM, so could possibly not be separate
How is the idea that all info needs to be rehearsed to move into LTM an oversimplification?
More relevant info is easier to remember
- Craig and Watkins said there are 2 types of rehearsal: maintenance + elaborative (latter explains this and is generally required to form LTMs)
If we do not understand info, regardless of the repeated rehearsal, it is unlikely to stay in LTM for long period of time
Sometimes info does not need to be rehearsed at all to form LTMs
- Eg. Flashbulb memories = Memories with high emotional content, which are easily stored
What is the conflicting evidence that suggests STM and LTM are made of multiple stores?
- K.F sustained brain damage from motorbike accident
- Severely impaired STM for verbal info only, not visual
- Suggests STM is not unitary as only part of it has been damaged (WMM better explanation)
- Amnesic patients have damaged episodic memories, but intact procedural + semantic memories
- LTM must have more than 1 store
It has been argued that LTM can be divided into:
- Explicit/Declarative memory = Memories that can be easily described and only recalled w/ conscious thought (require hippocampus)
- Implicit/Non-declarative memory = Memories that cannot be easily described and don’t require conscious thought to be recalled (do not require hippocampus)
What are the types of LTM and which are explicit/implicit?
- Episodic memory –> explicit
- Semantic memory –> explicit
- Procedural memory –> implicit
Episodic memory:
- Memory that gives individuals an autobiographical record of personal experiences
- Strength of memories influenced by emotions and degree of processing of info
- Helps individuals to distinguish difference between real and imaginative events
- Stored in hippocampus
- Contains ref to time and place
Prefrontal cortex: Initial coding of episodic memories
Neocortex: Consolidation and storage of memories
Hippocampus: Connects these together to create full memory
Semantic memory:
- Contains all knowledge an individual has learnt
- Strength of memories influenced by degree of processing of info
- Better sustained than episodic memories
- Does not always contain ref to time and place
Prefrontal cortex: Initial coding of episodic memories
Neocortex: Consolidation and storage of memories
- Stored in hippocampus
- Other evidence shows several brain areas are used
Procedural LTM:
- Memory permitting individuals to perform learned tasks
- Many occur early in life
- Allows ppl to simultaneously perform other cognitive tasks
Prefrontal cortex: Initial coding of episodic memories
Neocortex: Consolidation and storage of memories
- Stored in cerebellum + primary motor cortex
Briefly state the strengths and weaknesses of the types of LTM:
+ Supported by case studies
+ Evidence from brain scans
+ Can be used in real life applications
- Case studies have methodological issues
- Evidence of gender differences
Explain the case studies supporting types of LTM:
- H.M + Clive Wearing suffered brain damage that severely impaired episodic memories but had intact semantic + procedural memories
- Shows LTM has diff stores and is in different parts of brain
- C.L (8 yr old girl) sustained brain damage after removal of tumour. Could not form episodic memories but could form semantic (reported by Vicari et al (2007))
- P.M (68 yr old prof cellist) sustained brain damage impacting episodic + semantic. Could still read + play music so procedural memory was intact
What methodological issues do the case studies have?
- Lack of control as location of brain damage cannot be controlled
- Lacks population validity
Explain evidence from brain scans:
- Tulving (1989) asked pps to do diff memory tasks
- More activity in frontal + temporal lobes in semantic memory
- More activity in prefrontal cortex in episodic memory
How can the types of LTM be used in real life?
- Allows specific treatments to be developed
- Belleville (2006) showed it is possible to improve episodic memories in elderly people w/ impairments
What is the evidence of gender differences in LTMs?
- Herlitz et al (1997) assessed LTM abilities in 1000 Swedish pps
- Found females consistently performed better on task requiring episodic memories (could be due to higher verbal abilities)
- No gender differences in semantic memories
How else does the types of LTM lack population validity?
Everyone is different so research may not be able to be generalised
What did Baddeley and Hitch (1974) argue and what did they rename STM?
- STM is not a unitary store, as claimed by Atkinson and Shiffrin
- Argued that it has sub stores, which are each responsible for processing diff types of info
- Renamed it as working memory
Give a simplified flowchart of WMM:
Check photos
What are the 4 components of WMM and what name is given to 3 of these?
- Central executive
Slave systems: - Phonological loop
- Visuo-spatial sketch pad
- Episodic buffer
What does the central executive do?
- Overall control
- Monitors incoming info in all sensory forms
- Directs attention to important tasks (prioritises)
- Decides which slave systems are needed
What does the phonological loop do and what can it be divided into?
- Temporarily stores + rehearses word-based info in the order it arrives
Divided into:
1) Phonological store (inner ear)
2) Articulatory process (inner voice)
How does the phonological store work?
- Spoken words enter directly
- Written words must be converted into articulatory code before they can enter this store
- Holds info in speech-based form for 1-2 secs
How does the articulatory process work?
- Allows maintenance rehearsal of info
- Circulates info round and round in a loop
What does the visuo-spatial sketchpad do and what is it divided into?
- Stores and manipulates limited amount of visual and spatial info for a brief period of time
- Helps keep track of where we are in relation to other objects
Divided into:
1) Visual cache –> stores visual data
2) Inner scribe –> remembers arrangement of objects
When was episodic buffer added, why and what does it do?
- 2000
- WMM before did not allow for communication between slave systems
What does it do:
- Acts as a backup store
- Communicates w/ LTM and all info from other stores
- Records the order events happen
What is the capacity and coding of the central executive?
Capacity: Limited
Coding: Modality free
What is the capacity and coding of the phonological loop?
Capacity: 2 secs of speech
Coding: Acoustic
What is the capacity and coding of the visuo-spatial sketchpad?
Capacity: 3-4 objects
Coding: Visual
What is the capacity and coding of the episodic buffer?
Capacity: About 4 chunks
Coding: Visual, spatial + verbal
Which study supports WMM and what was its aim?
Baddeley and Hitch (1976)
Aim: Can pps use different parts of WMM at same time?
Procedure of Baddeley and Hitch (1976) study:
Pps asked to perform 2 tasks at same time (dual tasking technique):
1) Digit span task to repeat list of numbers
2) Verbal reasoning task to answer true/false to various qs
Results of Baddeley and Hitch (1976) study:
- As number of digits increased, pps took longer to answer VR qs but only by fractions of a sec
- Did not make any further errors despite the increased digits
Conclusion of Baddeley and Hitch (1976) study:
- VR task made use of central executive
- Digit span task made use of phonological loop
- Can be performed at same time
Briefly state the strengths and weaknesses of WMM:
+ Can account for dual tasking
+ Shows phonological loop + visuo-spatial sketchpad have limited capacity
+ Supporting case studies
+ Brain scanning evidence
+ Real life application
- Central executive role remains unclear
- Case studies lack population validity
- Dual-task studies lack ecological validity
- Link between WMM and LTM not explained (incomplete)
Which study accounts for dual-tasking and shows phonological loop + visuo-spatial sketchpad have limited capacity? What conditions were used to show this, with what results?
- Baddeley and Hitch (1976)
- Condition 1: 2 acoustic based tasks eg. Digit span + VR task
- Condition 2: 1 acoustic based task + 1 visual task eg. Digit span + Copying a drawing
- When both tasks required use of phonological loop (Condition 1), performance was impaired, however it was not when different parts of memory was used (Condition 2)
Which case study supports WMM?
- K.F had a severely impaired STM for verbal info only, not visual
- Supports at least 2 slave systems (phonological loop + visuo-spatial sketchpad)
What brain scanning evidence supports WMM?
- D’Esposito et al (1995) used fMRI scans
- Found prefrontal cortex activated when verbal + spatial tasks were performed together but not when done separately
- PET scans also showed diff brain areas activated during visual + verbal tasks
Why does WMM have greater face validity?
It explains how we carry out everyday tasks
What suggestions are there to show that the role of the central executive is unclear?
- Suggestion 1: Central executive directs attention and decides which slave system carries out a task
- Suggestion 2: Central executive may consist of many subcomponents
- Eslinger and Damasio (1985) studied EVR who did well on reasoning tests (suggesting central executive is intact) however had poor decision making skills (suggesting central executive is not intact)
Why do the case studies supporting WMM lack population validity?
Case studies are unique so it is hard to make a generalisation eg. K.F’s motorbike accident
In what way do the dual-task studies lack ecological validity?
- They are lab experiments
- Demand characteristics are likely to have been shown
- Tasks lack mundane realism
