Memory - Multi-Store Model

Question 1

What is memory?

Answer 1

It is the process of retaining and recalling information about events that have happened in the past.

Question 2

What are the main two types of memory?

Answer 2

Short term memory -
- Your memory for immediate events, which disappears if not rehearsed

Long term memory -
- Your memory for events that have happened in the past anywhere between 2 minutes and 100 years - it is a permanent memory store

• There is also sensory register which stores a huge amount of information from our senses for a very brief amount of time (around half a second)

Question 3

Two main types of coding

Answer 3

Acoustic - a memory linked to sounds / formatted information into sounds
Semantic - a memory linked to facts / information is stored as the factual meaning of the event

Question 4

Memory definitions

Answer 4

Capacity - The amount of information that can be stored
Duration - The length of time information can be held in the memory store
Coding - The format in which information is stored in the memory stores; it’s the process of converting information from one format to another

Question 5

What is the STM?

Answer 5

The short term memory temporarily stores information received from the sensory register and it is an active and changing memory system as it contains information currently being thought about.

Question 6

What is the LTM?

Answer 6

This involves storing memory over a long period of time, with any information being stored for more than 30 seconds counting as LTM. All information received here goes through the sensory register and STM first after undergoing different forms of processing.
Strong LTM’s can be easily recalled, whereas weaker ones need more prompting - LTMs are not passive, as they merge and change with other LTMs over time, which is why memories are necessarily constant and accurate. The process of shaping and storing LTM is also spread through multiple brain regions.

Question 7

Capacity in the STM

Answer 7

• Limited capacity that holds a small amount of information from the SR that has been paid attention too
• Chunking can help to improve the capacity by increasing the size of units of information in storage by giving them collective meaning
• It was said to have a capacity of about 5-9 items by Jacobs and Miller, with an average of 7 items and a minimum of 4
• However, there may be individual differences in STM capacity, as seen by Daneman and Carpenter (1980) who noticed that capacity varied between 5-20 items between those who have advanced and poor reading comprehension
• Evaluation - other factors such as age and practice influence STM capacity and nowadays STM limitations are mostly due to processing limitations associated with attention

Question 8

Capacity in the STM - Jacobs (1887)

Answer 8

• Developed a technique to measure digit span, where the researcher gives 4 digits and then the participant is asked to recall these in the correct order out loud
• If this is correct, the researcher reads out 5 digits and so on until the participant cannot recall the order correctly, determining the individual’s digit span
• Jacobs found that the mean span for digits across all participants was 9.3 items, and the mean span for letters was 7.3

Evaluation - the study was conducted a long time ago, and early psychological research often lacked adequate control, and so some participants may have been distracted during testing and therefore didn’t perform as well as they might
- This would mean results might not be valid because there were confounding variables that were not controlled, but these results have been supported by other studies, improving the validity of results

Question 9

Capacity in the STM - Miller (1956), Cowan (2001) and Simon (1974)

Answer 9

Miller (1956) -
- From a review of psychological research, he found that capacity / span of human memory is about 7 items, plus or minus 2, and people cope well with counting 7 flashing dots but not much more, which is generalised to digits, numbers and words
- He noted that 5 words can be recalled as well as 5 letters, and this is achieved by chunking, grouping sets of letters or digits into units or chunks

Cowan (2001) -
- Noted that Miller may have overestimated the capacity of STM, as he reviewed other research and concluded that the capacity of STM was only about 4 chunks. This suggests that the lower end of Miller’s estimate (5 items) is more appropriate as an estimation of capacity than 7 items

Simon (1974) -
- Although STM capacity should be measured in terms of chunks, this varies with the type of material being recalled and the amount of information contained within the chunks

Question 10

Capacity in the LTM

Answer 10

• The potential capacity of the LTM is unlimited; information can be lost due to decay and interference, but such losses don’t occur due to limitation of capacity
• Anokhin (1973) estimated that the number of possible neuronal connections in the human brain is 1 followed by 10.5 million kilometres of noughts, and so concluded that ‘no human yet exists who can use all the potential of their brain’ and this suggests that the capacity of LTM is limitless
• Wagenaar (1986) created a diary of 2,400 events over 6 years and tested himself in his event recall rather than date recall, and found excellent recall, suggesting that LTM capacity is extremely large

Evaluations -
- Anokhin; estimates are not certain
- Wagenaar - diary entries are case studies and are not representative of the general population; there are also issues of researcher bias from self-testing
- The capacity of LTM is assumed to be limitless, as research cannot determine a limitless capacity (neither proven or disproven)
- There may be an evolutionary basis to LTM; animal studies, like those of Fagot & Cook (1996) show that pigeons can memorise 1,200 picture response associations; Baboons still hadn’t reached their capacity after 3 years of training, memorising 5,000 associations
- This suggests that an enlarged memory capacity has a survival mechanism which has been acted upon through natural selection

Question 11

Duration of the STM

Answer 11

• The amount of time information remains in the STM without being lost is a maximum of 30 seconds, which can be extended through rehearsal of information, which if done consistently enough results in a transfer of the information to the LTM, where it will become more of a long-lasting feature - Peterson and Peterson; 18 seconds when rehearsal is blocked

Evaluation -
- Reitman (1974) suggested the brief duration of STM is due to displacement; as new information comes into STM it pushes out existing information due to its limited capacity
- There is little in the way of research evidence considering the STM duration of other forms of stimuli, like visual images

Question 12

Duration of the STM - Peterson and Peterson (1959)

Answer 12

Aim -> To investigate the duration of STM and provide empirical evidence for the MSM

Procedure -> A lab experiment was conducted in which 24 undergraduate students took part in 8 trials. On each trial, they were given a consonant syllable or trigram (three consonants) and a three digit number. The student was then asked to count backwards from the number in either 3s or 4s until told to stop, and this was to prevent rehearsal of the consonant syllable. On each trial, they were told to stop after a different amount of time - 3, 6, 9, 12, 15 or 18 seconds, known as a retention interval. After this, they were asked to stop counting and to repeat the trigram, and the percentage of trigrams correctly recalled was recorded for each retention interval.

Findings - The longer the interval delay, the less trigrams were recalled. Participants were able to recall 80% of trigrams after a 3 second delay, but after 18 seconds less than 10% of trigrams were recalled correctly

Conclusion - Information must be rehearsed to keep it in the STM, and it has a limited duration up to 18 seconds, when rehearsal is prevented. The results of this study also show that the STM differs from the LTM in duration

Evaluation - A limitation of this is that the stimulus material was artificial, as trying to memorise consonant syllables does not reflect most real-life memory activities, where what we try to remember is meaningful; may lack ecological validity, but often we do try to remember fairly meaningless things such as phone numbers, so the study is not totally irrelevant.

Question 13

Duration of the LTM

Answer 13

Depends on the individuals’ lifespan, as memories can last for a lifetime, with items that are originally well coded and contain certain LTMs having longer duration, like those based on skill rather than fact. Information does not have to be consistently rehearsed to retain it, making it different to STM.
- Evidenced by Bahrick et al (1975)
- Goldman and Seamon (1992) asked participants to identify odours of everyday products experienced in the last two years and odours not experienced since childhood, and although identification by name was better for more recent odours, there was significant identification of less-recent odours, suggesting that duration of olfactory information of LTM is very long-lasting

Evaluation -
- Sometimes information in the LTM appears to be lost, but there may simply be a problem of accessing information rather than it not being there
- The type of testing techniques used may affect findings from studies of LTM, and recall is often better when asking participants to recognise stimuli, rather than getting them to recall stimuli

Question 14

Duration of the LTM - Bahrick et al (1975)

Answer 14

Aim - To investigate the duration of the LTM

Procedure - Participants were given an opportunity sample of 392 American ex-high school students aged 17-74 years. High school yearbooks were obtained from the participants directly or from schools, and recall was tested in various ways including a free recall test, where participants recalled the names of as many of their former classmates as possible, and a photo recognition test where they were asked to identify former classmates from a set of 50 where some were from their yearbook and some weren’t.

Findings - participants who were tested within 15 years of their graduation were about 90% accurate in photo recognition and 60% accurate in the free recall (suggests the strength of triggered LTM), whereas after 48 years, recall declined to 70% on photo recognition and 30% in free recall.

Conclusion - LTM has a seemingly unlimited duration

Evaluation - this study has higher external validity as real-life memories were studied, as when studies on LTM have used meaningless pictures, recall rates were lower, but the downside of this ecologically valid studies is the risk of confounding variables are not controlled, such as participants having looked at yearbook pictures and rehearsed their LTM

Question 15

Coding in the STM - Acoustic

Answer 15

Information arrives from the SR in its original raw form, such as in sounds or vision, which is then encoded in a form the STM can more easily deal with, and this coding is done in several ways:
1. Visually - thinking of an image
2. Acoustically - repeating a sound / memorising a sound
3. Semantically - through meanings by using knowledge
- Research suggests that STM mainly codes acoustically (by sound) but other codes also exist; sensory codes such as visual are used for stimuli that cannot be remembered acoustically, such as faces or smells

• Baddeley (1966)
• Posner and Keele (1967) found that participants used visual code to assess differences in stimuli, such as recognising a difference in ‘A’ followed by ‘A’ and ‘A’ followed by ‘a’, illustrating how other codes not just acoustic are used in the STM

Question 16

Coding in the LTM - Semantic

Answer 16

• Coding in the LTM commonly happens semantically, with information being coded into meaning and memories, resulting in stronger coding and more retrievable information, and a deeper level of processing of a stimulus that occurs whilst being experienced
• With verbal material, coding is mainly semantic, but coding can also happen acoustically or verbally
• Baddeley (1966)
• Frost (1972) gave participants 16 drawings in 4 categories differing in visual orientation, like angle of viewing perspective, and the order of recall items suggested that participants used visual and semantic coding, implying evidence for visual and semantic coding in the LTM
• Nelson and Rothbart (1972) - acoustic coding also occurs; in a recall task using homophones, errors were made, suggesting acoustic coding in the LTM

Evaluation -
- It is hard to code smells and tastes semantically, and so they are recorded with other codes, and so there is evidence for the role of several forms of LTM encoding
- Different types of LTM involve different brain areas, with research suggesting they are coded in different ways, implying different types of coding for different LTMs

Question 17

Baddeley (1966) - Coding in the STM and LTM

Answer 17

Aim - To assess whether coding in the STM or LTM is mainly acoustic (sound) or semantic (meaning)

Procedure -
1. 75 participants were presented with one of 4 word lists repeated 4 times
- List A - acoustically similar, words that sounded similar
- List B - acoustically dissimilar; words that sounded different
- List C - semantically similar words - similar meaning
- List D - semantically dissimilar words - different meaning
2. STM - Participants were given a list containing the original words in the wrong order, and their task was to rearrange the words in the same order
3. The procedure was the same for the LTM, but with a 20 minute interval before recall, during which participants performed another task to prevent rehearsal.

Findings -
- For STM, participants given List A performed worst, with a recall of 10%. They confused similar sounding words, whereas recall for other lists was comparatively good at between 60-80%
- For LTM, participants with List C performed the worst, with a recall of only 55%, confusing similar meaning words, with recall for other lists being comparatively good at between 70-85%

Question 18

Baddeley (1966) - Conclusions and Evaluations

Answer 18

Conclusions -
- For STM, since List A was recalled the least efficiently, it suggests that there is acoustic confusion in STM, suggesting it is coded on an acoustic basis (acoustically different words were recalled easier, suggesting a merging of information from acoustic similarity)
- For LTM, since List C was recalled least efficiently, it suggests semantic confusion in LTM, suggesting LTM is coded on a semantic basis (semantically different words were recalled better, suggesting a merging of information from semantic similarity)

Evaluation -
- Baddeley’s conclusions make ‘cognitive sense’
- The small difference 7% difference in recall in the semantic lists on the STM trial suggests a level of semantic coding in the STM
- Lab study - shows causality, but lacks ecological validity, and cannot be replicated to check results
- Used an artificial stimuli rather than meaningful material, and the word lists had no personal meaning to participants, and so we should be cautious about generalising findings to different kinds of memory task e.g. people may use semantic coding in the STM for meaningful information, suggesting limited application and generalisability

Question 19

Comparing STM and LTM

Answer 19

Capacity -
- STM = limited to 5-9 items (Jacobs and Miller), LTM = limitless (Anokhin and Wagenaar)

Duration -
- STM = maximum of 30 seconds, usually around 18 seconds (Peterson and Peterson)
- LTM = any duration (Bahrick)

Coding - Baddeley
- STM = acoustic
- LTM = semantic

Question 20

What is a model?

Answer 20

• It is a representation of what is being described
• A model of memory is a representation of memory based on available evidence, providing an analogy of how it works

Question 21

Who constructed the multi-store memory model?

Answer 21

• Atkinson and Shiffrin (1968) suggested that the memory is made up of three unitary (separate / different) stores;
  1. The sensory register
  2. The STM
  3. The LTM
• This is a structural model of memory known as the multi-store memory model
• They suggest that each store is different and information is transferred from one store to another in a fixed, linear sequence

Question 22

What is the sensory register?

Answer 22

• This is the memory store for each of our 5 senses e.g. iconic store for visual information (1/3 of a second), echoic store for auditory information (3-10 seconds) and the haptic store for feelings such as pressure and pain detected through the sensory receptors which are then transferred to the afferent neurons, postcentral gyrus and parietal lobe (1-2 seconds), and so each store is coded differently
• A stimulus from the environment passes into the sensory register, and it receives all the information holding it very briefly - the duration of the SR is less than half a second
• The capacity is however very high e.g. each eye has around 1 million cells, each storing information
• Very little of what passes into the sensory register passes further into the memory system however, but it will if it is paid attention too - attention is the key process

Question 23

The Multi-Store Memory Model

Answer 23

1. Stimulus from the environment enters the SR
2. The SR; each store coded differently, duration of less than half a second and a high capacity; 95-99% of all information is lost as we do not pay attention to it
3. Due to paying attention, this information passes into the short-term memory
4. The STM - duration of 18-30 seconds without rehearsal, capacity of 5-9 items and acoustic coding; information is lost through response
5. Other information that is rehearsed remains in the STM through maintenance rehearsal (maintenance rehearsal = repeating information to oneself to memorise)
6. Information is transferred into the LTM through prolonged / elaborate rehearsal of information
7. The LTM - duration of a lifetime, unlimited capacity, semantic coding
8. Information can then be retrieved from the LTM back into the STM

SR -> Attention -> STM -> Maintenance rehearsal -> STM
-> Prolonged rehearsal -> LTM
LTM -> STM when information is needed

Question 24

Evaluation of the Multi-Store Memory Model - Supporting evidence `

Answer 24

1. Baddeley (1966) found that we mix up acoustically similar words when we are using our STMs and mix up semantically similar words when we use our LTMs
   - This clearly supports the MSM by showing that the LTM is indeed semantically coded and the STM is acoustically coded as they were confused by their respective store but not by the other. This is also supports that each store has different codes as described by the model, and that the stores are separate, making it an externally valid model of memory coding and separation of stores
2. HM underwent brain surgery to relieve his epilepsy which involved removing part of his hippocampus - when his memory was assessed in 1955 (when he was 31) he believed it was 1953 and that he was 27. His LTM was tested over and over again but never improved with practice. He would read the same magazine repeatedly without remembering it, and he as unable to recall what he had eaten the same day. However, he performed well on tests of his immediate memory span (STM)
   https://www.ted.com/talks/sam_kean_what_happens_when_you_remove_the_hippocampus?language=en
   - This supports that the STM and LTM are two separate stores because only one was affected by the removal of the hippocampus, suggesting that the stores are therefore unitary and located in different places with a sequence of transfer of information through the hippocampus as described by the model - this makes it an externally valid explanation and makes it applicable to understanding the structure of memory, and it is a good model as it explains how they are different and how the hippocampus relates to the LTM

Question 25

Evaluation of the MSM - Undermining Research

Answer 25

1. Shallice and Warrington (1970) studied a patient with amnesia known as KF. They found his STM for digit span was very poor when they read aloud to him, but his recall was much better when he read it to himself. Further studies of KF and other amnesia patients suggest that there is another STM store for non-verbal sounds. - This is a limitation of the MSM as it does not explain the range of stores that possibly exist within the STM, making the model too reductionist and simplistic as it does not explain the details of each store fully. It does not account for other STM stores and therefore is not a broad enough explanation for the structure of memory 2. According to the MSM, it's the amount of rehearsal that matters - however, Craik and Watkins (1973) found that there are actually different types of rehearsal - maintenance (as described in the MSM in the STM store) and prolonged / elaborate to transfer information to the LTM. Elaborative rehearsal involves linking the information to existing knowledge or you think about what it means - This is a serious limitation of the MSM because it suggests that the amount of rehearsal is not important, undermining the emphasis placed on it as a key process in the MSM of retention of information. It suggests that the process is much simpler to transfer information from the STM to the LTM and relies more on type of rehearsal than time, therefore affecting its ability to describe rehearsal and transfer, making it lack external validity and broadness as a memory model

Question 26

Evaluation of the MSM - Undermining Research cont.

Answer 26

3. There is lots of evidence that there is more than one type of LTM. For example, we have one LT store for our memories of the facts of the world, and different ones for memories of how to ride a bike - This is a limitation of the MSM because it does not account for the different types of LTM, affecting the extent of its representation of memory in the LTM and impacting its external validity, making it to narrow of an explanation and making it a singular description rather than a multi-faceted model

Question 27

Supporting evidence for the MSM - evaluation

Answer 27

3) Glazer and Cuntiz showed that after participants were given a word list, they tend to remember the first and last words not the middle (primary effect on first ones and recency effect on the other), supporting the existence of different LTM and STM stores

Question 28

Sensory Register research

Answer 28

Sproeing - - Flashed up a letter grid and found that people were unable to recall all 12 letters - When they were flashed up with music, the recall was better, as they paid attention to what letters were assigned to each piece of music - Importance of attention