Memory evaluation Flashcards
Capacity studies
- Joseph Jacobs, average span 9.3 for numbers, 7.3 for letters
- George Miller magic number, 7 plus or minus 2, 5 words 5 letters
Capacity evaluation
- Cowan 2001 – reviewed a variety of studies on the capacity of STM and concluded that STM is likely to be limited to about 4 chunks, this suggests that STM may not be as extensive as first thought
- Research on the STM for visual information found that 4 items was the limit therefore the lower end of millers range is more appropriate
- Simone 1974 found that people had shorter memory span for larger chunks such as 8 word phases then smaller chunks such as one-syllable words
- STM capacity is not the same for everyone
- Jacobs found that recall increased with age – eight year olds could remember 6.6 digits whereas 19 year olds could remember 8.6 digits
- The STM increase may be due to a gradual increase in brain capacity or the idea that people develop strategies to improve their digit span as they get older
Duration studies
STM - Lloyd and Margaret Peterson - studied duration, 24 students were given a consonant syllable and three digit number, intervals of 3,6,9,12,15,18, participants were 90% on 3 seconds and 2% on 18 seconds
LTM - Bahrick et al - 400 people aged 17-74, photo recongition and free recall name list of participants, 15 years afterwards and 48 years afterwards
photo recognition = 90% then 70%
free recall - 60% then 30%
Duration Evaluation
- Trying to memorise constant syllables does not truly reflect most every day memory activities where what we are trying to remember is meaningful
- However we do try to remember groups of numbers and letters e.g. phone number and postcodes so does have some relevance
- In the Peterson’s study participants were counting numbers in their STM and may displace or overwrite the syllables to be measured
- Reitman 1974 used auditory tones instead of numbers so displacement tones would not occur he found that STM duration was longer suggesting that displacement in the Peterson’s study was due to displacement than decay and was not measuring the duration of STM
- Nairne et al 1999 – found that items could be recalled after 96 seconds
Coding studies
- acoustic and semantic coding
- Baddeley 1966a and 1966b
- test effects of acoustically and semantically similar words
- if the words were acoustically similar than had difficulty remembering them in STM but not LTM suggesting that STM is acoustically coded
- if the words were semantically similar then they had difficulty remembering them in LTM but not STM suggesting that LTM is semantically coded
Coding evaluation
- Frost 1972 – showed that long term memory recall was related to visual as well as semantic categories and Nelson as Rothbart 1972 found evidence of acoustic coding in LTM
- Varies according to circumstance
- Some experiments have shown that visual codes are used in STM
- Brandimote et al 1992 – found that participants used visual coding in STM if they were given a visual task and prevented to do an verbal rehearsing in the retention interval they had to say la la la before performing a visual recall task therefore they only used visual codes
- Other research has shown that STM sometimes uses a semantic code such as Wickens et al 1976
- STM was tested by asking participants to recall a word from a list immediately after hearing it whereas LTM was tested by waiting 20 minutes which is questionable whether this was LTM or not
Multi store memory model evaluation
Strengths
Supporting evidence
- Controlled lab studies on capacity duration and coding support the existence of a separate short term and long term store which is the basis of the MSM
- Studies using brain techniques have also demonstrated that there is a difference between STM and LTM
- Beardsley 1997 – found that the prefrontal cortex is active during STM but not LTM tasks
- Squire et al 1992 – also used brain scanning and found the hippocampus is active when LTM is engaged
Case studies
- Different parts of the brain are involved in STM and LTM – from case studies with brain damage
- Scoville and Milner 1957 – brain damaged patient, his brain damage was caused by an operation to remove the hippocampus from both sides of his brain to reduce the serve epilepsy he suffered, HM personality and intellect remained intact but he could not form new LTM’s although he could remember things before the surgery
Limitations
The multi-store model is too simple
- MSM suggests that both STM and LTM are single unitary stores – research does not support this
- Research shows that STM is actually divided into a number of qualitatively different stores – it isn’t just a difference in terms of the kind of memory that is stored there
- The same is true for LTM – number of qualitatively different kinds of LTM each behave differently for example maintenance rehearsal can be explained by long term storage in semantic memory but idoesn’t explain long term episodic memories
Long term memory involves more than maintenance rehearsal
- Craik and Lockhart 1972 – suggested that enduring memories are created by processing that you do rather than through maintenance rehearsal, things that are processed more deeply are more memorable because of the way that they are processed
- Craik and Tulving 1975 – give participants a list of nouns and asked a question that involved shallowed or deep processing – asked whether a word was printed in capital letters or asked whether the word fitted in a sentence, the participants remembered more words in the task involving deep processing rather than shallow processing, this deep elaborative processes is a key process in creating long term memories
The working memory model Evaluation
Strengths
Dual task performance
- Hitch and Baddeley 1976 supported the existence for CE in a study
- Task 1 occupied the CE, participants were given a statement “A is followed by B” and shown two letters “BA” and asked to say true or false
- Task 2 involved the articulatory loop e.g. say “the the the” repeatedly or involved both the central executive and the articulatory for example saying random digits
- Task 1 was slower when task 2 involved both the central executive and the articulatory loop, this demonstrates the dual task performance effect and shows that the CE is one of the component of the working memory model
Evidence from brain-damaged patients
- Shallice and Warrington 1970 – studied a man called KF, his short term forgetting of auditory information was greater than that of visual stimuli, his auditory problems were limited to verbal material such as letters and digits but not meaningful sounds therefore his brain damage was restricted to the phonological loop
- Another patient SC, had good learning abilities with the exception of being unable to learn word pairs that were presented out land, therefore had damage to the phonological loop – Torjano and Grossi 1995
- Farah et al 1988 – LH had been involved in a road accident performed better on spatial tasks rather than those involving visual imagery suggesting separate visual and spatial systems
Limitations
The central executive
- Some psychologists think it is just the same as paying attention, too vague and doesn’t really explain anything
- Critics believe that one CE is wrong and it is probably made up of different components
- Eslinger and Damasio 1985 studied EVR they had a cerebral tumour removed, but performed well on tests requiring reasoning so his CE was still intact, but he had poor decision making skills therefore he would spend hours trying to decide where to eat this suggests that the CE was not fully intact
- The account offered of the CE is unsatisfactory because it fails to explain anything as its probably more complex
Evidence from brain damaged patients
- Brain injury is traumatic this may change behaviour so that a person performs worse on certain tasks
- May have difficulties paying attention and therefore underperform on tasks
Evaluation of types of long term memory
Evidence from brain scans
- Three types of memory is supported by brain scans, it has been shown that different areas of the brain are active when the different kinds of LTM are active
- Episodic memory = hippocampus and other parts of the temporal lobe and the frontal lobe, memories of different elements of an event may be distributed in other areas but are all connected by the hippocampus to form one episode
- Semantic = temporal lobe
- Procedural memory = cerebellum – this is involved in the control of motor skills and the motor cortex, basal ganglia and limbic system are also involved
Distinguishing procedural and declarative memories
- HM – destruction of hippocampus affected the ability to make new long term memories but his old ones were intact, so basically he could still form new procedural memories but not episodic or semantic memories
- Corkin 2002 discovered that he could draw a figure by looking at reflection in a mirror which is procedural memory but had no memory that he drew it which is episodic/semantic memory
Distinguishing episodic and semantic memories
- Relationship between the episodic and sematic memories raise the question of whether episodic memories are a gateway to forming semantic memories or whether semantic memories can form independently
- Hodges and Patterson 2007 – studied patients with Alzheimer’s disease and found that some patients retain the ability to form new episodic memories but not semantic memories, therefore this is a single dissociation
- Not sufficient enough evidence that two are distinct as the episodic memory could be placing greater general demand on the mental processing and that’s why it is more affected by brain damage – therefore researches need to look for double dissociation
- Irish et al 2011 was an example of double dissociation – found Alzheimer’s patients have the reverse – poor semantic memories but intact episodic memories suggesting that semantic memories could form independently
Evidence from patients with brain damage
- Low population validity
- HM – difficult to be certain of the parts of the brain that have been damaged until the patient has died
- Damage to a particular area does not mean that the area is responsible for that behaviour, may be acting as a relay station
Priming and a fourth kind of LTM
- Priming describes how implicit memories influence the responses a person makes to a stimulus - for example if a person is given the word yellow and then asked to name a fruit later the chance that they name banana is greater than if they are not primed – answers are automatic and unconscious
- Research has shown that priming is controlled by a brain system separate from the temporal system that supports explicit memory – lead to suggestion that there is a fourth kind of LTM, the perceptual representation system memory (PRS) – automated enhanced of a specific stimulus
- Spiers et al 2001 – studied memory in 147 patients with amnesia – all procedural memories and PRSs were intact but other two systems were not this supports the notion of two kinds of implicit memory not affected by amnesia
Explanations for forgetting: interference studies
- retroactive - George Muller - gave participants a list of nonsense syllables to learn for 6 minutes and then after a retention period they were asked to recall the lists, performance was less good if participants had been giving intervening tasks between initial learning and recall - shown paintings and asked to describe them
- proactive - Underwood 1957, analysed findings from a number of studies and concluded that when participants have to learn a list of words they do not learn the list of words encountered later on in the sequence as well as the list of words that they encounter earlier on
- similarity of test materials - McGeoch and McDonald experiemented with teh effects of similarity of materials, gave participants a list of 10 adjectives during whcih they learned list B followed by a recall, if list B was synonyms they performed worse that if it was a list of non sense words
- real world study - Baddeley and Hitch and the Rugby players
Explanations for foregetting: interference evaluation
artificial research
- Evidence that supports PI and RI, but most of the experiments are lab based and often use artificial and contrived equipment therefore does not relate to everyday memory
- Low ecological validity – participants may lack motivation to remember the lists which allows interference to have more of an effect
- On the other hand interference has been observed in everyday situations
only explains some situations of forgetting
- Interference effects do not occur often
- Special conditions are required for interference to lead to forgetting so therefore it is relatively unimportant
- Anderson 2000 concluded that interference plays a role in forgetting but how much is plays a role is unclear
accessibility versus availability
- Researchers question whether interference effects actually cause a memory to disappear or are just temporary
- Ceraso 1967 – found that if memory was tested after 24 hours there was spontaneous recovery whereas recall was the same, so interference occurs because memories are temporarily not accessible rather than lost
Real world application to advertising
- Danaher et al 2008 – found that both recall and recognition of an advertisers message were impaired when participants were exposed to two advertisements for competing brands within a week – serious problem considering the amount of money advertisers spend only to have the effect dulled by interference
- Suggest that one strategy might be to enhance the memory trace by running multiple exposures to advert in one day rather than spread out over a week which reduces interference
individual differences
- Evidence that some people are less affected by PI than others
- Kane and Engle 2000 – demonstrated that individuals with a greater working memory span were less susceptible to PI than those with a low span
- Having a greater working memory span meant having greater resources to consciously control processing and counteract the effects of PI
Explanations for forgetting: retrieval failure studies
- Encoding specificity principle - Tulving and Pearlstone, demonstrated the value of retrieval cues where participants had to learn 48 words belonging to 12 categories, then recall either free or given category name
- Context- dependent forgetting - Abernethy 1940 - arranged for a group of students to be tested before a course then in the same room with same instructor, or difffernet room, or different instructor
- State-depending forgetting - Goodwin et al - drunk or sober
Evaluation of explanations for forgetting; retrieval failure
lot of research support
real world application
- use it to improve recall
- Abernethy’s research suggests that you should revise in the room where you take the exam, may be unrealistic but you can use your imagination
- Smith 1979 - showed that just thinking of the room where you did the original learning was just as effective as doing the test in the same room
retrieval cues do not always work
- really not that effective to improve exam performance
- the information that you are learning is related to a lot more than just cues therefore it does not work
- learning complex associations which are less easily triggered by cues - outshining hypothesis - a cues effectiveness if reduced by the presence of better cues
- Smith and Vela 2001 - context effects are largely eliminated when learning meaningful material
the danger of circularity
James Nairne 2002 - criticised what he calls the myth of encoding-retrieval match
- claims that the relationship between encoding cues and later retrieval is a correlation rather than a cause - cues do not cause retrieval but are just associated with retrieval
Baddeley made a similar criticism
- pointing out that the encoding specificity principle is impossible to test because it is circular - if a stimulus leads to the retrieval of a memory that it must have been encoded in memory if it does not lead to a retrieval of a memory then according to the encoding specificity principle it cannot have been encoding but it is impossible to test for an item which has not been encoded
retrieval failure explains interference effects
Tulving and Psotka 1971 - demonstrated that interference effects are due to the absence of cues
- participants were given 6 different word lists to learn each consisting of 24 words divided into 6 different categories
- after each word list was presented they were asked to write down how many they could remember
after all the lists were presented they were given the category names and asked to recall all the words from the lists, the categories acted as cues
- some participants only learned one list, then other learned 2 and so on
- according to interference theory the more lists a participant had to learn the worse their performance would become
- However when participants were given cued recall effects of interference disappeared - participants remembered 70%of the words regardless of how many lists that they have been given - shows that information is there but cannot be retrieved and shows that retrieval failure is more important explanation of forgetting that interference
Accuracy of eyewitness testimony; Misleading information studies
- Loftus and Palmer
- conformity effect
- repeat interviewing
Accuracy of eyewtiness testimony: misleading information evaluation
Research support
- Research supports this
- Loftus conducted a memorable study involving cut outs of bugs bunny, and college students were asked to evaluate advertising material about Disneyland, and embedded in this material was misleading information about bugs bunny or Ariel and these could not have been seen in Disney
- participants were assigned to the Bugs, Ariel or control condition and all had visited Disneyland
- participants in the Bugs or Ariel condition were more likely to report that they had shaken hands with the characters than the control group
EWT in real life
Loftus research suggeted that EWT was unreliable but not all researchers agree
- Loftus may not represent real life because it was carried out in lab conditions
- Foster et al - found that if participants thought they were watching a real life robbery and also thought that their responses would influence the trial their identification of a robber was more accurate
- Yuille and Cutshall found evidence of a greater accuracy in real life, witnesses to an armed robbery in Canada gave accurate reports to the crime four months after it had taken place even though they had initially been given two misleading questions suggesting that misleading information may have less influence on real life EWT
real world applications
- Criminal justice system relies of EWT and identification in prosecuting crimes
- psychological research has been used to warn teh justice system of problems with EWT
- DNA exoneration cases confirm this showing that eyewitness identification was the largest single factor contributing to the conviction of innocent people
individual differences
- Age differences could be consequence of source monitoring
- eyewitness acquires information from two sources from observing the event itself and from subsequent suggestions
- number of studies have found that compared to younger subjects elderly people have difficulty remembering the source and become prone to the misleading information
may be response bias
- Bekerian and Bowers suggested it might be a response bias after all and they compared participant performance in two conditions
- in one condition participants were given a set of questions which matched with data that was consistent or inconsistent, they were later asked the same questions but in a different order
- participants were less accurate when the data was inconsistent
- in condition 2 participants were given the same task but this time the set of questions were presented in the same order and there was now a difference between having been giving consistent or inconsistent data this suggests that the order of questions had a significant effect and therefore memory change was due to response bias not storage
