Memory Flashcards
What is memory?
Memory is the process by which we retain and recall information about events that have happened in the past.
What is coding?
The format in which information is stored in the memory stores. It’s the process of converting information from one format to another.
What is capacity?
The amount of information that can be stored.
What is duration?
The length of time information can be held in the memory store
According to Jacobs, what is the capacity of STM? How did he study this?
Jacobs (1887) developed a technique to measure digit span. The researcher gives, for example, four digits and then the participant is asked to recall these in the correct order out loud. If this is correct, the researcher reads out five digits, and so on until the participant cannot recall the order correctly. This determines the individual’s digit span. Jacobs found that the mean span for digits across all participants was 9.3 items. The mean span for letters was 7.3.
According to Miller, what is the capacity of STM?
From a review of psychological research, Miller (1956) found that the span (capacity) of human memory is about 7 items (plus or minus 2). People cope well with counting 7 flashing dots but not much more – same for digits, numbers and even words. He also noted that people can recall 5 words as easily as 5 letters. They do this by chunking – grouping sets of letters or digits into units or chunks.
What is the capacity of LTM?
Potentially unlimited
Evaluate research into the capacity of memory in at least two ways
Jacobs - However, Jacobs’ study was conducted a long time ago. Early research in Psychology often lacked adequate control. For example, some participants may have been distracted while they were being tested so they didn’t perform as well as they might. This would mean that the results might not be valid because there were confounding variables that weren’t controlled. Therefore, we can’t be certain that the results are a valid reflection of the capacity of STM. However, the results have been supported in other research, supporting its validity.
Miller - However, he may have overestimated the capacity of STM. Cowan (2001) reviewed other research and concluded that the capacity of STM was only about four chunks. This suggests that the lower end of Miller’s estimate (5 items) is more appropriate than 7 items.
What did Peterson and Peterson do and find?
Aim: To investigate the duration of short-term memory and provide empirical evidence for the multi-store model.
Procedure: A lab experiment was conducted in which 24 undergraduate students took part in 8 trials (8 tests). On each trial they were given a consonant syllable or trigram (meaningless three-consonant syllables, e.g. TGH) to remember 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. The counting backwards was to prevent any mental rehearsal of the consonant syllable (which would increase the student’s memory). On each trial, they were told to stop after a different amount of time - 3, 6, 9, 12, 15 or 18 seconds. This is called a retention interval. After this, they were asked to stop counting and to repeat the trigram. 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 seconds delay. However, after 18 seconds less than 10% of trigrams were recalled correctly.
What did Peterson and Peterson conclude the duration of STM is?
Information must be rehearsed in order to keep it in STM. Short-term memory has a limited duration (up to 18 seconds) but in the exam we can say up to 30 seconds, when rehearsal is prevented. The results of the study also show the short-term memory is different from long-term memory in terms of duration.
What did Bahrick et al. do and find?
Aim: To investigate the duration of LTM.
Procedure: Participants were 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 some schools. Recall was tested in various ways, including: (1) free recall test - where participants recalled the names of as many of their former classmates as possible; (2) photo recognition test - where they were asked to identify former classmates in a set of 50 where some were from their yearbook and some weren’t.
Findings: Participants who were tested within 15 years of graduation were about 90% accurate in photo recognition. After 48 years, recall declined to about 70% for photo recognition. Free recall was less good. After 15 years, this was about 60% accurate, dropping to 30% after 48 years.
What did they conclude the duration of LTM is?
LTM has a seemingly unlimited duration.
Evaluate research into the duration of memory in at least two ways
Peterson and Peterson - a limitation of this is that the stimulus material was artificial. Trying to memorise consonant syllables does not reflect most real-life memory activities where what we are trying to remember is meaningful. So we might say that the study lacked external validity and may therefore underestimate the duration of STM for more realistic information. However, we do sometimes try to memorise fairly meaningless things e.g. phone numbers, so the study is not totally irrelevant and may tell us something about the duration of STM in these circumstances.
Bahrick et al - this study has higher external validity as real-life memories were studied. When studies on LTM have used meaningless pictures, recall rates were lower. Therefore the study seems to tell us about the duration of LTM with realistic tasks. The downside of such real-life research is that confounding variables are not controlled e.g. participants may have looked at their yearbook photos and rehearsed their memory over the years. Therefore, the study lacks internal validity and we can’t be certain that the results reflect the true duration of LTM without rehearsal.
How did Baddeley study the coding of STM and LTM? What did he find?
Baddeley (1966) gave different lists of words to four groups of participants to remember:
Group 1 – acoustically similar – words that sounded similar e.g. cat, cab, can
Group 2 – acoustically dissimilar – words that sounded different e.g. pit, few, cow
Group 3 – semantically similar – words with similar meanings e.g. great, large, big
Group 4 – semantically dissimilar – words with different meanings e.g. good, huge, hot
Participants were shown the original list of words and asked to recall them in the correct order. When they had to do this recall task immediately after hearing it (STM recall), they tended to do worse with acoustically similar words. This suggests that information is coded acoustically in STM.
If participants were asked to recall the word list after a time interval of 20 minutes (LTM recall), they did worse with the semantically similar words. This suggests that information is coded semantically in LTM.
What did he conclude about the coding of STM and LTM?
STM is coded acoustically
LMT is coded semantically
Evaluate research into the coding of memory in (just Baddeley)
The study used quite artificial stimuli rather than meaningful material. The word lists had no personal meaning to participants. This means that we should be cautious about generalising the findings to different kinds of memory task e.g. when processing more meaningful information, people may use semantic coding even for STM tasks. This suggests that the findings from this study have limited application about the coding of STM and LTM.
What is the Multi-Store Model of Memory (MSM)?
A structural model (representation) of memory. It was the first complex model of human memory. They suggest that each store is different/separate (unitary) and information is transferred from one store to another in a fixed, linear sequence.
What is meant by a unitary store and how many are there according to the MSM?
It means different or seperate. The MSM is made up of three
What is the sensory register?
The sensory register is the memory stores for each of our five senses e.g. iconic store for visual information, echoic store for sound information.
What is the coding, capacity and duration of the sensory register?
Coding - each store of the sensory register are coded differently (iconic coded visually, echoic coded acoustically etc.).
Capacity - high capacity e.g. over one hundred million cells in one eye
Duration - less than half a second
According to the MSM, how is information transferred from the sensory register to STM?
If you pay attention to it
According to the MSM, how is information transferred from STM to LTM?
Prolonged rehearsal
According to the MSM, how is information transferred from LTM to STM?
Retrieval
What are the strengths of the MSM?
Supporting evidence from previous studies
Supporting evidence - Baddeley’s study - supports that STM and LTM are coded differently which supports that they are unitary
Supporting evidence - Peterson and Peterson found that duration of STM is up to 30 seconds without rehersal and Bahrick et al. Found that the duration of LTM is up to a lifetime which supports that they are unitary (separate)
What are the weaknesses of the MSM?
Weaknesses of the supporting evidence
Weakness - Baddeley and Peterson and Peterson used artificial stimuli –> not externally valid, so they are not very strong support for the idea that the STM and LTM are unitary stores
Weakness - There may be actually more than one type of LTM but the model suggests that it is all one unitary store
What happened to HM? How does his case both support and undermine the MSM?
HM underwent brain surgery to relieve his epilepsy which involved removing his hippocampus. When his memory was assessed in 1955 (when he was 31), he thought it was 1953 and 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. He couldn’t recall what he had eaten earlier the same day. However, he performed well on tests of immediate memory span (a test of STM e.g. Star task).
This supports that STM and LTM are two unitary stores that are qualitatively different because one can be damaged whilst the other remains intact, as proposed by the MSM. They may even be stored in different parts of the brain. Counterargument: however, the research was a unique case study of a brain damaged individual. You need to explain how.(not a lot of people had a brain injury exactly like his) Therefore, it isn’t particularly strong support for the MSM as the results may not be generalisable to other people (you need to explain who) (people who haven’t had the surgery/ had their memory affected like he had)
What happened to KF? How does his case undermine the MSM?
Shallice and Warrington (1970) studied a patient with amnesia called KF. They found that his STM for digits was very poor when they were read out loud to him, but his recall was much better when he was able to read them to himself. Further studies of KF and other people with amnesia suggest that there could be another short-term store for non-verbal sounds.
This is a limitation of the MSM because research suggests that there must be at least one short-term store to process visual information and one to process auditory information, which undermines the unitary store of STM proposed by the MSM. The working memory model includes these separate stores of STM. (when we have done the WMM you will be able to say what these stores are and how therefore the WMM may be a better model of STM than the MSM)
What did Craik and Watkins suggest about rehearsal? How does this undermine the MSM?
Ignore
According to the MSM, it’s the amount of rehearsal that matters. Craik and Watkins (1973) found that there are actually different types of rehearsal. There are two main types: maintenance rehearsal (as described in the MSM) and elaborative rehearsal which is needed to transfer information from STM to LTM. Elaborative rehearsal is when you link the information into your existing knowledge, or you think about what it means.
This is a serious limitation of the MSM because it is another research finding that cannot be explained by the model. This suggests it may not be a completely valid model of how memory works.
What happened to Clive Wearing? How does his case undermine the MSM?
There is lots of evidence that there is more than one type of LTM. Clive Wearing suffers from a severe form of amnesia that resulted from a viral infection that attacked his brain, damaging the hippocampus and associated areas. Before this infection, Clive was a world-class musician and he can still play the piano brilliantly and conduct a choir but he can’t remember his musical education. He can remember some other aspects of his life before his infection, but not others. For example, he knows he has children from an earlier marriage, but cannot remember their names. He recognises his second wife, Deborah, and greets her joyously every time they meet, believing he has not seen her in years, even though she may have just left the room for a few minutes. He has no problem understanding the meaning of words and can carry out a conversation effectively.
This is a limitation of the MSM because research suggests that there must be at least one long-term store to store our knowledge of the world and one to store our knowledge of how to do things, which undermines the unitary store of LTM proposed by the MSM.
Name and define the three types of LTM according to Tulving.
Episodic - memories of life events. Can be expressed verbally (recalled with conscious effort) – available for conscious inspection (explicit). Time-stamped – with reference to time and place. May be less resistant to amnesia/forgetting
Semantic - memories of knowledge of the world. Can be expressed verbally (recalled with conscious effort) – available for conscious inspection (explicit). Not time-stamped. May be less resistant to amnesia/forgetting
Procedural - memories of how to do things (motor skills/actions). Difficult to explain verbally (recall without conscious awareness) – unavailable for conscious inspection (implicit). Not time-stamped. May be more resistant to amnesia/forgetting
Which types of LTM were intact and damaged for Clive Wearing? How does this support the types of LTM?
His procedural memory is intact because he can still play the piano and conduct a choir.
His episodic memory is impaired because he can’t remember having seen his wife recently…
His semantic memory is partly intact because he can remember his wife’s name and the meaning of lots of words, but he can’t remember his children’s names.
This supports Tulving’s view that there are different memory stores in LTM. One store can be damaged but other stores are unaffected. This is clear evidence that nor only are there different types of LTM, but that they are stored in different parts of the brain.
Counterargument: the evidence is based on unique case studies of brain damaged individuals. Therefore, the research isn’t strong support for the different types of LTM
What did Tulving et al. Do and find? How does this support the types of LTM?
Brain scans
There is evidence from brain scan studies the different types of memory are stored in different parts of the brain. Tulving et al. (1994) got their participants to perform various memory tasks while their brains were scanned using a PET scanner. They found that episodic and semantic memories were both recalled from the prefrontal cortex. The left prefrontal cortex was involved in recalling semantic memories. The right prefrontal cortex was involved in recalling episodic memories.
This supports the view that there is a physical reality to the different types of LTM within the brain. It has also been confirmed many times in later research studies, further supporting the validity of this finding.
What real-world application is there of knowing that there are different types of LTM?
Being able to identify different aspects of LTM allows psychologists to target certain kinds of memory in order to better people’s lives. Research has found that episodic memories could be improved in older people who had a mild cognitive impairment. The trained participants performed better on a test of episodic memory than a control group. Episodic memory is the type of memory most affected by mild cognitive impairment, which highlights the benefit of being able to distinguish between types of LTM – it enables specific treatments to be developed, supporting the external validity of the theory.
Other people have disagreed that there are three LTM stores. What do they propose instead and how is this a weakness of the types of LTM?
They accept that procedural memories represent one type of LTM. But they argue that episodic and semantic memories are stored together in one LTM store that they call declarative memory (i.e. memories that can be consciously recalled). Procedural memories are non-declarative. It is important to get these distinctions right so that any treatments that are developed are effective and so that the theory is valid i.e. it accurately explains the differences between types of LTM.
What is the working memory model (WMM) a representation of?
The working memory model (WMM) is a representation of how short-term memory is organised and how it functions. It was proposed by Baddeley and Hitch in 1974 as an updated version of STM. It suggests that STM is an active processor of different types of information using sub-units that are coordinated by a central decision-making system.
How is the WMM different to the MSM in how it represents this type of memory?
The MSM represents a simplified version of STM whereas the WMM consists of four main components which are qualitatively different in terms of their capacity and coding
Describe the function, coding and capacity of the central executive
Function: coordinates activity of the three slave systems. Takes in information from senses and LTM, makes decisions and allocates slaves systems to tasks.
Capacity: Limited processing; no storage
Coding: Any sensory modality
Describe the function, coding and capacity of the phonological loop
Function - processes and temporarily stores sound based information and preserves order they arrive in
Capacity - 2 seconds
Coding - acoustically
Subcomponents: Phonological store: stores sound based information (words you hear)
Articulatory process: maintenance rehearsal (inner voice)