Memory Flashcards
Atkinson and Shiffrin’s (1968)
Multi-Store Model of Memory (MSM)
They suggested that memory is made up of three separate stores: sensory register (SR), short-term memory (STM) and long-term memory (LTM).
What does the MSM suggest?
According to the model, memories are formed sequentially and information passes from one component to the next, in a linear fashion.
Coding
The way in which information is changed and stored in memory.
Duration
Length of time that information is held in the memory store
Capacity
The amount of information that can be stored.
How does information enter the sensory register?
Via our senses
SR: Capacity
Large
SR: Duration
~Half a second
Modality-specific
SR is modality-specific, ie whichever sense is registered will match the way it is consequently held (eg a taste held as a taste)
What happens if the sensory information is paid attention to?
It moves into the STM for temporary storage, which will be encoded visually (as an image), acoustically, (as a sound) or, less often, semantically (through its meaning).
STM Capacity
7 +/- 2 items
STM Duration
~ 18-30 seconds
However, it can be extended by verbal rehearsal (rehearsal loop)
How is STM coded?
Acoustically (sound)
What happens if information in STM is rehearsed?
Rehearsed information is transferred to LTM, either through maintenance rehearsal (repeating the information) or elaborating rehearsal (linking to information already in LTM).
Capacity of LTM
Unlimited
Duration of LTM
Lifetime/years
How is information in the LTM coded?
Semantically (by meaning)
According to the MSM, how do we recall information from our LTM to STM?
Through retrieval.
But information can be lost via displacement (new info) or decay (lost over time)
SR: Coding
Raw/unprocessed information from all five senses (modality specific)
Researches that support the MSM
Jacobs found that the STM store has a limited capacity of 7+/-2 items;
Miller (1956) supports the idea that our STM has a capacity of 7+/- 2 ‘chunks’ of information / items;
Peterson & Peterson (1959) support the idea of a limited duration in STM;
Baddley (1966) supports the notion of different types of encoding in STM and LTM;
Bahrick (1975) supports the idea of an unlimited duration in LTM
Miller (1956): Capacity of STM - AIM
To investigate the capacity of STM
Miller (1956): Capacity of STM - METHOD
Literature review of published investigations into perception and STM, from the 1930s to 1950s
Miller (1956): Capacity of STM - RESULTS
This existing research suggested that organising stimulus input into a series of chunks enabled STM to cope with about seven ‘chunks’, and this is why more than seven digits, words or even musical notes could be remembered successfully.
Miller (1956): Capacity of STM - CONCLUSION
Encoding can expand the capacity of STM and enable more information to be stored there, albeit briefly.
Strength of Miller (1956): Research support
One strength of Miller’s theory is that there is research support. For example, Jacobs (1887) conducted an experiment using the digit span test, to examine the capacity of STM for numbers and letters, Jacobs used a sample of 443 female students (aged 8-19) from the North London Collegiate School. Participants had to repeat a string of numbers or letters in the same order and the number of digits/letters was gradually increased, until the participants could no longer recall the sequence. Jacobs found that the students had an average span of 7.3 letters and 9.3 words. This supports Miller’s notion of the capacity of STM being 7 +/- 2 items.
Weakness of Miller (1956)
Miller’s (1956) research into STM did not take into account other factors that affect capacity, For example, age could also affect STM and Jacob’s (1887) research acknowledged that STM gradually improved with age.
[Key study] Peterson and Peterson (1959): Duration of STM - AIM
To investigate how different short intervals containing an interference task affect the recall of items presented verbally, and to infer the duration of STM.
Peterson and Peterson (1959): Duration of STM - METHOD
The sample consisted of 24 male and female university students. The verbal items tested for recall were 48 three-consonant nonsense syllables (eg JBW or PDX) spelled out letter by letter. These have since been named ‘trigrams’. There were also cards containing three-digit numbers (eg 360 or 294). The researcher spelled the syllable out and then immediately said a three-digit number. The participant had to count down backwards in either 3s or 4s (as instructed) from that number. This was to prevent maintenance rehearsal (interference task). At the end of the pre-set interval between 3 & 18 seconds a red light went on and the participant had to recall the trigram.
Peterson and Peterson (1959): Duration of STM - RESULTS
They found that the longer the interval the less accurate the recall. At 3 seconds, around, 80% of the trigrams were correctly recalled, whereas at 18 seconds, only 10% were recalled correctly.
Peterson and Peterson (1959): Duration of STM - CONCLUSIONS
STM has a limited duration of approximately 18 seconds unless maintained. Furthermore, if we’re unable to rehearse information it will not be passed to LTM, providing further support for the MSM and the idea of discrete components.
Strength of Peterson and Peterson (1959)
One strength of Peterson and Peterson’s (1959) study is that it was highly controlled. The study took place in a laboratory in Indiana University. As a result, Peterson and Peterson had a high degree of control for extraneous variables, which makes their procedure easy to replicate to test reliability.
Weakness of Peterson and Peterson (1959)
One weakness of Peterson and Peterson’s (1959) study is that it has low levels of ecological validity. In this study, participants were tasked to recall three-letter nonsense trigrams, which is unlikely to occur in real life, termed mundane realism. As a result, it is difficult to apply these results to everyday examples of memory, making it harder to conclude if the duration of STM may be longer for more important information, such as a vital phone number (eg 999).
Two issues with Peterson and Peterson’s (1959) sample
- Demand characteristics (changing behaviour to assist the experimenter)
- Individual differences (different strategies of memorising)
[Key study] Bahrick (1975): Duration of LTM - AIM
To investigate the duration of LTM
Bahrick (1975): Duration of LTM - METHOD
392 American university graduates were shown photographs from their high school yearbook and for each photograph participants were given a group of names and asked to select the name that matched the photographs.
Bahrick (1975): Duration of LTM - FINDINGS
90% - correctly matched the names and faces 14 years after graduating
60% - correctly matched the names and faces 47 years after graduation
Bahrick (1975): Duration of LTM - CONCLUSION
Bahrick concluded that people could remember certain types of information, such as names and faces, for almost a lifetime. These results support the MSM and the idea that our LTM has a lifetime duration (at least 47 years), and is semantically coded.
Strength of Bahrick’s (1975) study on the duration of LTM
One strength of Bahrick’s (1975) study on the duration of LTM is that it has high levels of ecological validity as the study used real-life memories. In this study, participants recalled real-life information by matching pictures of classmates with their names. Therefore, these results reflect our memory for real-life events and can be applied to everyday human memory, thereby supporting the MSM.
Weakness of Bahrick’s (1975) study on the duration of LTM
One weakness of Bahrick’s (1975) study on the duration of LTM is that it lacks population validity. This is because the sample consisted of 392 American university graduates, therefore making it harder to generalise the results to other populations such as students from Europe. Additionally, students typically have better memory as they would be used to memorising a lot of information for school. As a result, we are unable to conclude whether other populations would demonstrate the same ability to recall names and faces after 47 years.
Strength for the MSM: Brain scans
Evidence from brain scans has shown that different areas of the brain are active when performing STM tasks (hippocampus and subiculum) and LTM tasks (motor cortex). This hippocampus is also involved in transferring short-term memories into long-term memories. This suggests that different brain regions are responsible for the different components of the MSM, supporting the idea that our memory is made up of discrete stores.
Strength of the MSM: Case study of HM
The case study of HM suggests that he could still form short term memories but was unable to form new long term memories. This shows that the STM and LTM are unitary, ie they work independently of each other.
List some strengths of the case study of HM
- Highly detailed in depth data
- High ecological validity
- Case study is useful / the only method for studying certain topics due to ethics or rarity of a phenomena
List some weaknesses of the case study of HM
- No cause and effect can be inferred as it is impossible to control variables
- Lack of generalisability as a sample is too small and unrepresentative
- Low reliability as it’s very difficult to replicate
- Lacks validity due to hawthorne effect (changing behaviour if you know you’re being observed)
- Case studies are time consuming and expensive
- Ethical issues (lack of informed consent)
Weakness of case study on HM: Ethical issues
One weakness of the case study of HM is that it had many ethical issues. One of the important parts of conducting psychological studies is that informed consent must be obtained. However, HM was unable to give full informed consent. This is due to the fact that his long term memory was damaged and he was unable to form new long term memories. As a result, even if HM given consent, he may not have remembered giving consent. If something negative had happened, and he revoked his consent, researchers simply had to wait a couple of hours for him to forget this, and continue with their testing, thus resulting in ethical implications. Therefore, this reduces support for the MSM of memory, as the results cannot be used as evidence.
However, the case of HM has been important in the development of our knowledge and understanding of memory. Without HM, we would not know that the STM and LTM worked independently. Therefore it may be argued that breaching ethical issues was important for the development of psychology.
[Opposed MSM] Shallice & Walrrington ‘s case study on KF - AIM
To investigate the relationship between STM and LTM when STM is impaired.
Shallice & Walrrington ‘s case study on KF - METHOD
A case study was conducted on KF, who fractured his parietal-occipital lobe in a motorcycle accident which led to epilepsy. He had damaged his STM but his LTM remained intact. KF was asked to repeat numbers, letters and word strings aloud.
Shallice & Walrrington ‘s case study on KF - FINDINGS
KF’s digit recall was poor when read out to him (auditory) but better when he could read the digits himself (visual).
Shallice & Warrington ‘s case study on KF - CONCLUSION
The case of KF demonstrated that his deficit in STM was for verbal information and that the STM for visual material was normal. This opposes the MSM which suggests that the STM is a unitary store by suggesting that there may be more than one type of STM.
How does KF support MSM?
KF’s STM was severely impaired whilst his LTM remained intact. This supports the view that STM and LTM are separate and distinct stores and therefore supports the proposals of the MSM as it shows that it is possible to damage only one store in memory.
Who did research into coding of memory?
Baddley (1966)
Baddley (1966): Coding - AIM
To establish whether STM and LTM encode information in different ways.
Baddley (1966): Coding - METHOD
Gave four 10 word lists to four participant groups.
A: Acoustically similar - words sound the same
B: Acoustically dissimilar - words sound different
C: Semantically similar - words have related meaning
D: Semantically dissimilar - words are unrelated
Baddley (1966): Coding - FINDINGS
He found that immediate recall was worst for list A (acoustically similar) and recall after 20 minutes was worst with list D (semantically dissimilar).
Baddley (1966): Coding - CONCLUSION
This suggests that the coding in STM is acoustic, as recalling list A (acoustically similar) was most difficult as the recalling of similar sounds caused confusion in recall. It also suggests that coding in LTM is semantic, as recalling list D (semantically dissimilar) was most difficult.
Tulving (1985)
Tulving criticised the MSM and suggested that LTM has 3 separate stores: semantic, procedural, episodic.
Declarative (memory)
Can be put into words
Explicit (memory)
Consciously recalled
Non-declarative (memory)
Difficult to put into words
Implicit (memory)
Memory that can’t be consciously recalled
Types of LTM: Semantic memory
Memory that includes facts, meanings, concepts and knowledge of the world.
E.g. a bike has two wheels.
Declarative
Not time stamped - may not recall when learnt/encoded
Explicit - recalled consciously
Not autobiographical
Resistant to forgetting
How deeply processed influences strength of the memory
Parahippocampal cortex
Types of LTM: Episodic memory
Memory of experiences and specific events
Declarative
Time stamped - stored with reference to time and place
Explicit - recalled consciously
Autobiographical
Easiest memories to forget
Level of emotion felt at the time influences strength
First coding in the prefrontal cortex. Stored across the brain connect3d by hippocampus
Types of LTM: Procedural memory
Unconscious memory of skills also known as muscle memory
E.g. skill of riding a bike
Non-declarative
Not time stamped - often learnt in childhood
Implicit - not recalled consciously
Not autobiographical
Very resistant to forgetting
How many times practiced influences the strength of the memory
Motor cortex and cerebellum
Research support for different types of LTM: case study of Clive Wearing
Clive Wearing has retrograde amnesia so he cannot remember his musical education (episodic), however he remembers facts about his life (semantic). He can also play the piano (procedural). He is also unable to encode new episodic or semantic memories due to also having anterograde amnesia, but under experimental conditions he is able to gain new procedural memories through repetition. This support’s Tulving’s idea that there are 3 types of LTM: semantic, episodic and procedural memory, since Wearing lacks episodic memory completely, can recall but not encode semantic memories, and his procedural memory is functional.
Weakness of using Clive Wearing’s case study
Lack of control:
Research was not conducted in a lab, meaning it cannot eliminate the effect of confounding and extraneous variables, resulting in a lowered reliability.
