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.
Contradicting evidence for the division of LTM
Cohen and Squire (1980) argued that episodic and semantic memories are stored together in one LTM store (declarative memory).
Types of LTM: Supporting Evidence - Neuroimaging evidence
There is evidence from brain scan studies that the different types of memory are stored in different parts of the brain. Tulving et al (1994) got their participants to complete memory tasks as their brains were being scanned using a PET scanner. It showed that episodic and semantic memories were both recalled from an area called the prefrontal cortex which is divided into two ( left and right hemisphere) where the left hemisphere is dominant in semantic memories and the right hemisphere is dominant in episodic memories. This therefore suggests that there are different types of LTM.
Who proposed the Working Memory Model (WMM)?
Baddley and Hitch (1974)
Why was the WMM proposed?
To replace the STM store of the MSM due to criticisms of the STM
What does the WMM focus on?
STM
Central executive
‘Boss’ of the WMM.
It controls attention and directs information to the two slave/sub systems: the phonological loop and visuo-spatial sketchpad.
It can also process information from any sensory modality.
Limited in capacity - 4 items
Phonological loop
Processes auditory (sound) coded information
Temporary storage system for verbal information which has two components:
1. Articulately control process (‘inner voice’) - holds info via sub-vocal repetition
2. Phonological store (‘inner ear’) - holds recently heard words
Has a limited capacity of what can be said in 2 seconds (word length effect)
Articulatory control process
Allows for subvocal repetition of acoustic information
Phonological store
Temporary storage space for coding acoustic information, which has a limited capacity.
Visuo-spatial sketchpad
Processes visual and spatially coded information, thought of as the “inner eye”
Temporary storage system for visual and spatial information which also has two components:
1. Inner scribe
2. Visual cache
Inner scribe
Deals with the manipulation of mental images
Visual cache
Has a limited capacity for coding visual and spatial information
Episodic buffer
Added to the WMM in 2000, as the model needed a general store to hold and integrate information from the VSS, PL, CE and LTM.
Binds and integrates information from all the components and passes the information to LTM. It therefore codes both visual and acoustic information, but also has a limited capacity.
Baddley and Hitch - Dual Task Method (1976)
Baddley and Hitch aimed to test if the STM was unitary or not.
Participants were asked to complete a verbal reasoning task whilst reciting 6 digits, ie complete 2 tasks simultaneously.
They found that as the number of digits increased in the digit span tasks, participants took longer to answer the reasoning questions, but not much longer - only fractions of a second. And, they didn’t make any more errors in the verbal reasoning tasks as the number of digits increased.
This study suggests the STM has more than one store as participants were able to complete the task. The verbal reasoning task made use of the central executive task and the digit span task made use of the phonological loop.
Dual task studies provide evidence for the existence of multiple components within our STM and support the idea of a separate phonological loop and visuo-spatial sketchpad.
Weakness of Baddley and Hitch - Dual Task Method (1976)
A weakness of this study is that it lacked mundane realism as the dual task method doesn’t reflect real life processes. It is unlikely that an individual would be completing a verbal reasoning task whilst reciting a 6 digit number in their daily life. This makes it harder to generalise the findings of the study, resulting in a decrease in external validity.
WMM - Oversimplified
One issue with the WMM is that it only focuses on the STM, and the link between the WMM and MSM is not fully explained. The WMM provides a detailed description of our STM, but no information on how information is processed and transferred from STM to LTM and back again. Therefore, the WMM is an incomplete model of memory and other theories/models are required to gain a complete picture of this complex cognitive phenomenon.
Methodological issues with KF
KF was a case study, meaning we cannot control for extraneous or confounding variables
What does the WMM suggest?
STM must be more complex than just a single unitary store that only exists to pass information on to LTM. STM must be an active processor, holding multiple different types of information simultaneously while being worked on.
WMM - KF
It was found that KF has a selected impairment to his verbal STM, caused by a brain injury; however the visual functioning of his STM is not affected. This suggests the PL and VSS subsystems are separate processes located in separate brain regions.
Explanations for forgetting
Proactive interference
Retroactive interference
Retrieval failure due to the absence of cues
What causes interference?
Interference happens when two pieces of information conflict with each other, resulting in forgetting one or both pieces of information or distortion of memory. This mainly happens in the LTM.
Proactive interference
Old memory interferes with the learning of new info
Retroactive interference
Learning of new memory interferes with the recall of old information from LTM.
Underwood and Postman (1960) - AIM
To see if new learning interferes with previous learning (retroactive interference)
Underwood and Postman (1960) - METHOD
Participants were divided into two groups:
A - asked to learn a list of word pairs (e.g. CAT - TREE). They were then asked to learn a second set of word pairs (e.g. CAT - PLUG)
B - asked to learn the first list only
Both groups were asked to recall the first list of word pairs.
Underwood and Postman (1960) - FINDINGS
Group B’s recall of the first list was more accurate than Group A
Underwood and Postman (1960) - CONCLUSION
New learning interfered with participant’s ability to recall the first list.
Underwood and Postman (1960): Lacks validity
This study may lack validity as we cannot be sure that retroactive interference occurred here. It’s uncertain whether list 2 had an impact on the recall of list 1 or not.
Group B may have had better recall of list 1 due to using different methods of remembering.
For example, by using a memory improvement strategy.
This means that we cannot be sure that retroactive interference actually had an impact on recall in this study, therefore reducing support for the theory that new learning interferes with the recall of an older memory.
Effect of similarity [Explanations for forgetting]
Interference is more likely to occur when the two pieces of information are similar, this is due to response competition.
Effect of time sensitivity [Explanations for forgetting]
Interference is less likely to occur when there is a large gap between the instances of learning.
Who conducted research into the effects of similarity? [Explanations for forgetting]
McGeoch and McDonald (1931)
McGeoch and McDonald (1931) - AIM
To investigate whether interference affects forgetting in LTM
McGeoch and McDonald (1931) - METHOD
Participants learnt a list of adjectives until they could recall them perfectly. Some of the participants then spent 10 minutes resting while the others learned new material. The new material varied in similarity to the original test.
McGeoch and McDonald (1931) - FINDINGS
The more similar the new material to the original, the more the recall of the original list declined. Participants who spent 10 minutes resting without any new material to learn had the highest recall.
McGeoch and McDonald (1931) - CONCLUSION
This shows that retroactive interference affected recall. It indicates that the more similar the later material, the greater the interference and the higher the level of forgetting.
McGeoch and McDonald (1931) - Low ecological validity
The experiment has low ecological validity as it was a laboratory study, which is not set up like everyday life and furthermore the task is not something you would experience in everyday life (lacks mundane realism). This means that it’s harder to generalise the findings of the study to a wider population.
However, it can be argued that the lab setting gives the study a higher level of control of extraneous and confounding variables, which may increase the reliability of the study.
Retrieval failure
Retrieval failure is when we don’t have the necessary cues to access memory.
The memory is available but not accessible.
Tulving and Thomson (1973) - Encoding Specificity Principle (ESP)
They argued that memory is most effective when there is a cue present at encoding and present at retrieval.
They suggested that environmental cues and mental cues aid recall.
Two types of retrieval failure due to absence of cues
- Context-dependent failure
- State-dependent failure
Context-dependent forgetting
Recall depends on external cue eg weather or a place
State-dependent forgetting
Recall depends on internal cue eg feeling upset or being drunk
Cue
A ‘trigger’ of information that allows us to access a memory
Godden and Baddley (1975) - AIM
To investigate the effect of contextual cues on recall
Godden and Baddley (1975) - PROCEDURE
Participants were deep sea divers. They were divided into four groups. All groups were given the same list of words to learn. Four conditions:
1. Learnt underwater and recalled underwater
2. Learnt underwater and recalled on land
3. Learnt on land and recalled on land
4. Learnt on land and recalled underwater
Godden and Baddley (1975) - RESULTS
Groups 1 and 3 recalled 40% more words than groups 2 and 4.
Godden and Baddley (1975) - CONCLUSION
Retrieval failure happens if the external cues available during learning are different from the ones available at recall.
Weakness of Godden and Baddley (1975)’s study - lacks validity
P: Lacks validity - cannot be sure if the context had an impact on recall as some participants may have used memory improvement strategies.
E: For example, participants may have created a story.
E: This would’ve been easier for them to remember the words.
L: Therefore we cannot be sure that context had an impact on recall.
Weakness of Godden and Baddley (1975)’s study - demand characteristics
P: demand characteristics
E: repeated measures study
E: Participants could’ve guessed the aim of the study after participating in all 4 conditions
L: this reduces internal validity
Carter and Cassaday (1998) - AIM
To examine state-dependent forgetting
Carter and Cassaday (1998) - PROCEDURE
Participants had to learn lists of words and passages of prose and then recall the information.
Some participants were given antihistamine/hay fever drugs which made them slightly drowsy, creating a different state from the usual ‘normal’ state of being awake and alert.
Four conditions:
1. Learn on drug and recall when on drug
2. Learn on drug and recall when not on drug
3. Learn not on drug and recall when on drug
4. Learn not on drug and recall when not on drug
Carter and Cassaday (1998) - FINDINGS
In the conditions where the learning and recalling state matched, memory was improved. If it was not matched then recall was significantly poorer.
Carter and Cassaday (1998) - CONCLUSION
When the physiological/emotional cues that are present at the time of encoding are missing at the time of retrieval (recall), state-dependent forgetting is likely to occur.
Eye witness testimony (EWT)
The evidence given in court or a police investigation by someone who has witnessed a crime or accident.
Factors that affect the accuracy of EWT
- Misleading information
- Leading questions
- Post-event discussion
- Anxiety
Leading questions
A question which suggests a certain answer because of the way it is phrased.
Why do leading questions affect EWT? (1)
Response-bias explanation:
Wording of the question has no real effect on memories but influences how they decide to answer.
E.g. “smashed” could lead to participants giving a higher speed estimate of a car in a car crash.
Loftus and Palmer (1974) - AIM
To investigate the effect of leading questions on the accuracy of eyewitness testimony.
Loftus and Palmer (1974) - PROCEDURE
A sample of 45 American students were divided into five groups of 9. In an independent measures design, all of the participants watched a video of a car crash and were then asked a specific question about the speed of the cars. Loftus and Palmer manipulated the verb used in the critical question, for example: “How fast were the cars going when they smashed/collided/bumped/hit/contacted with each other?”, with “hit” being the control group.
Loftus and Palmer (1974) - FINDINGS
The group who were given the word ‘smashed’ estimated a higher speed than other groups (~41 mph).
The group who were given the word ‘contacted’ estimated the lowest speed (~32 mph)?
Loftus and Palmer (1974) - CONCLUSION
The results show clearly that the accuracy of EWT is affected by leading questions and that a single word in a question can significantly affect the accuracy of our judgement.
Why do leading questions affect EWT? (2)
Substitution explanation:
Wording of the leading question actually changes the participant’s memory of the event.
Loftus’ later study - AIM
To investigate further how leading questions can affect EWT
Loftus’ later study - METHOD
A different sample of 150 American students were divided into three evenly-sized groups. All of the students watched a one-minute video depicting a car accident and were then given a questionnaire to complete. One group was asked: “How fast were the cars going when they smashed into each other?”. Another group was asked: “How fast were the cars going when they hit each other?”. The final (control) group was not asked about the speed of the vehicles.
One week later, participants were asked a series of questions about the accident. The critical question was “Did you see any broken glass?”. There was no broken glass in the video clip.
Loftus’ later study - FINDINGS
32% of the participants in the verb ‘smashed’ condition reported seeing broken glass; 14% of the participants in the ‘hit’ condition reported seeing glass; and 12% of the control group reported seeing broken glass.
Loftus’ later study - CONCLUSION
Participants who gave higher estimates in the ‘smashed’ condition were more likely to think they saw broken glass, as a result of the earlier leading question.
‘Smashed’ connotes faster speed.
Their memory of the original event was distorted by the question used one week earlier, demonstrating the power of leading questions.
Weakness of Loftus’ study
P: lab study
E: no emotional arousal as participants were watching videos
E: Christianson interviewed 110 witnesses to bank robberies. Those who had been threatened remembered more details than those who had been onlookers.
L: Therefore those who were more emotionally aroused recalled more. This reduces support for Loftus’ theory that leading questions can have a negative impact on memory.
C/C: lab study allows for a high degree of control which reduces the chance of extraneous variables. This increases the validity of the results making it easier for the study to be replicated.
Weakness of Loftus’ study (2)
P: lacks population validity
E: students only
E: students have less experience in driving.
L: cannot generalise to older, more experienced drivers
Weakness of Loftus’ study (3)
P: individual differences
E: Anastasi and Rhodes (2006) found that 35-45 year olds have more accurate recalls than 55-78 year olds.
E: Older people recall less accurately
L: reduces internal validity
CC: all groups more accurate when identifying people of their own age - own age bias
Post-event discussion
Co-witnesses may discuss the details of a crime or accident, following an accident
Gabbert et al (2003) - AIM
To investigate the effect of post-event discussion on the accuracy of EWT
Gabbert et al (2003) - PROCEDURE
Sample consisted of 60 uni students and 60 older adults.
Participants were paired together and watched the same crime from different points of view. They then discussed what was seen.
Gabbert et al (2003) - FINDINGS
71% mistakenly recalled aspects of the event they did not see in the video.
Control group (individuals) - no discussion: 0%
Gabbert et al (2003) - CONCLUSION
Witnesses often go along with each other either to win social approval or they believe they are wrong.
Post-event discussion can have a powerful effect on the accuracy of EWT.
Strength of Gabbert et al (2003)’s study
P: population validity
E: two different populations were tested (university students and older adults)
E: little difference was found between these two conditions
L: her results provide good population validity and allow us to conclude that post-event discussion affects younger and older adults in a similar way.
Anxiety
A state of emotional and physical arousal
Johnson and Scott (1976) - AIM
To investigate whether anxiety affects the accuracy of EWT
Johnson and Scott (1976) - PROCEDURE
Participants were seated in a waiting room.
Two conditions:
1. Man holding pen with grease in his hands (low anxiety condition)
2. Man holding paper knife covered in blood (high anxiety condition)
Participants were asked to identify man from 50 photos.
Johnson and Scott (1976) - FINDINGS
Pen condition: 49% accuracy
Knife condition: 33% accuracy
Johnson and Scott (1976) - CONCLUSION
Tunnel theory of memory argues that a witness’s attention narrows on a weapon because it is a source of anxiety. Therefore anxiety has a negative effect on recall.
Weakness of Johnson and Scott (1976)
P: deception and harm
E: participants were not aware of the nature of the experiment and were exposed to harm
E: some of the participants were exposed to a man holding a bloodied knife which could’ve caused extreme anxiety
L: ethical guidelines were broken
Weakness of Johnson and Scott (1976)’s study (2)
P: cultural bias
E: samples of participants were either from Britain or America
E: individualistic society differs from collectivist cultures.
L: lacks generalisability
Yuille and Cutshall (1986) - AIM
To investigate the effects of anxiety open a real life shooting
Yuille and Cutshall (1986) - PROCEDURE
Interviewed 13 witnesses of a deadly shooting 4 months after the event.
Yuille and Cutshall (1986) - FINDINGS
Witnesses resisted misleading information and those with the most stress (closest to shooter) produced the most accurate EWT.
Yuille and Cutshall (1986) - CONCLUSION
Misleading information and anxiety may not be a significant problem for real world EWT
Yerks-Dodson Law of Arousal
EWT accuracy increases as anxiety increases because the witness becomes alert. However, at one point anxiety will become too high and more stress/distraction results in lower accuracy.
[inverted U shape]
Strength of research on the limitations of EWT
Real world applications eg development of cognitive interviews - designed to reduce the influence of schemas on the accuracy of recall.
Cognitive interview
A method of interviewing eye witnesses to help them retrieve more accurate memories.
Four steps of cognitive interview
- Report everything
- Context reinstatement
- Recall from changed perspective
- Recall in reverse order
Cognitive interview - Report everything
Witness recalls every detail they can remember, even those that may seem trivial.
Cognitive interview - Context reinstatement
When a person recalls the context of the event eg the time of the day, the weather, who they were with or even their feelings. These details can act as a trigger, to help the person recall more information. There are clear links here between this and context-dependent and state-dependent remembering.
Cognitive interview - Changed perspective
When a person considers the event from someone else’s point of view. Eg from the offender’s pov.
Cognitive interview - Reverse order
Where a person recalls the events in reverse chronological order
Geiselman (1985) - AIM
To examine the effectiveness of the cognitive interview
Geiselman (1985) - PROCEDURE
A sample of 89 students watched a video of a simulated crime. Two days later, the students were interviewed using the standard police interview or the cognitive interview.
Geiselman (1985) - RESULTS
The students who were interviewed using the cognitive interview recalled significantly more correct information than those interviewed using the standard interview. In addition, the number of errors by both groups was similar.
Geiselman (1985) - CONCLUSION
The cognitive interview is effective in improving the quantity of information recalled and does not lead to an increase in incorrect information.
Weakness of Geiselman (1985)
P: cultural bias
E: researchers and participants are from a western background
E: research into police interview procedures in a western (individualistic) society may not apply to a non western (collectivist) society
L: lacks generalisability
