Memory Flashcards
(22 cards)
Coding, Capacity and Duration - A01 (Coding)
Sensory Memory Store (SMS): encodes variously, iconic: register through eyes, echoic: register through ears
Short Term Memory (STM): encodes acoustically, Baddeley’s research; Baddeley (1966) gave four groups of participants a list of words to remember, each list was different (acoustically similar, acoustically dissimilar, semantically similar, semantically dissimilar), the ppts repeated the words immediately after they had seen the list of words, those with the acoustically similar list struggled more, when repeating the words after 20 minutes the group with the semantically similar list struggled, suggesting that STM encodes acoustically and LTM encodes semantically
Coding, Capacity and Duration - A03 (Coding)
- Research support Baddeley’s STM research is Conrad’s study and findings, Conrad conducted a study where he showed ppts letter strings of 6 consonants that were either acoustically similar or dissimilar, the ppts were significantly more successful at recalling the letter strings that were acoustically dissimilar, supporting Baddeley’s conclusion that the STM encodes acoustically.
- A strength is that Baddeley’s research identifies a clear difference between the STM and LTM, as it is a critical understanding when researching memory, as well as leading to the multi-store model, this conclusion has also stood the test of time, strengthening it and making it more credible and reliable in future research.
- A limitation is that Baddeley’s study used artificial stimuli rather than realistic scenarios, the words lists have very little practical application to real-life, suggesting that Baddeley’s findings may not be meaningful and have limited application
Coding, Capacity and Duration - A01 (Capacity)
SMS: very large capacity
STM: Miller found that the STM holds an average of 7 items (+2 or - 2), meaning that it holds chunks of information based on amount rather than specific numbers or letters, eg. phone numbers are remembered in chunks of letters …07795….5437
LTM: unlimited capacity, Azevedo found that there are 86 +/- billion neurons in the brain, 10K connections each neuron
Coding, Capacity and Duration - A03 (Capacity)
- Jacobs’ research (1887) supported that information is collected in chunks (chunking), he measured the digit span by reading our four digits to ppts for them to repeat immediately after, and then repeats the process increasing the number of digits each time the mess up, he found that the mean digit span across the ppts was 9.3 and the mean span for letters was 7.3, supporting Miller’s conclusion that our STM capacity is 7 +/- 2.
- Jacobs’ study has also been replicated since it was conducted in 1887, meaning it likely lacked adequate controls and had various confounding variables such as being distracted during the study, despite this, Jacobs’ findings have been confirmed by Bopp and Verhaegen in 2005, suggesting the study is/was a valid test of the digit span in STM
- A limitation of Miller’s research is that he overestimated the STM, Cowen (2001) reviewed other research and concluded that the STM capacity holds chucks of 4 +1/-1, suggesting that the lower end of Miller’s findings (around 5) is more appropriate than 7 items
Coding, Capacity and Duration - A01 (Duration)
SMS: very brief duration, Sperling’s research (1960), he showed ppts a chart to look at for 1/20th of a second and then asked them to recall all the letters they remembered after, he found that they recalled 4/5 letters from the chart but they were aware of more, he also got the ppts to recall single lines of letters that were recited in different voice pitches, starting high pitched and getting lower as well as varying the delay between each recall, he found that the greater the delay the worse the recall was, concluding that the SMS duration is very brief (only about 4 items) and that as letters/pictures fade so does the memory
STM: 18-30 seconds, Peterson and Peterson conducted a study (1959) where they tested 24 ppts in 8 ‘trials’, where they were given trigrams of consonant letters to remember (eg. YLG) as well as being made to count backwards from a three digit number, they varied the interval of which they made the ppts count backwards (3, 6, 9, 12, 15, 18 seconds) and measured their recall each time, the backwards counting was implemented to avoid the ppts rehearsing the trigrams in their head, they found that after 3s the 80% of the ppts recalled successfully and after 18s only 3% recalled successfully, making them conclude that the STM duration is about 18 seconds, unless information is rehearsed/repeated over again.
LTM: duration of up to a lifetime, Bahrick (1975) conducted his yearbook study with 392 American ppts from between 17 and 74 years old, yearbooks from obtained from ppts and from school and their recall was tested in various ways: photo recognition from 50 presented images, recall of names from their graduating class year, ppts tested within 15 years of graduating had 90% accuracy when recalling photos, after 48 years photo recall declined to 70%, the free name recall for the ppts who graduated within 15 years was 60% and dropped to 30% after 48 years, concluding that the LTM may last up to a life time depending on the material/information
Coding, Capacity and Duration - A03 (Duration)
- A limitation of Peterson and Peterson’s study is that the stimulus material was artificial and therefore meaningless to real-life scenarios, the study is not completely meaningless since we sometimes remember trigrams of digits (eg. phone numbers, post codes) however it does not reflect most everyday memory activities, meaning the study lacks external validity
- Alternately, Bahrick’s yearbook study has very high external validity since it was carried out with relation to the ppts’ real lives, the researchers investigated meaningful memories (names and faces), when LTM duration studies were conducted with meaningless pictures/icons the recall rates were lower (Shepard 1967), suggesting that Bahrick’s study reflects a more realistic measure of the LTM duration
Multi-Store Model of Memory - A01
Atkinson and Shiffrin (1968,71) proposed the multi-store model as an explanation for how information is encoded into the SMS, STM and LTM.
SMS (or sensory register) collects all stimuli from the environment which passes through the store briefly. If we hold attention on the stimuli, it encodes into our short term memory. When the information is repeated (rehearsed) is transfers into our long term memory, where it can be stored for up to a lifetime, and retrieved in the future
Multi-Store Model of Memory - A03
- Research support for the MSM is research conducted by Baddeley (1966), where he similarly determined that the STM and LTM are distinct, different stores, his research found that STM encodes information acoustically whereas the LTM encodes information semantically, implying that they function separately and therefore supporting Atkinson and Shiffrin’s conclusion that they are distinct
However, the study conducted by Baddeley (as well as most of the others) used stimuli made up of letters and numbers, however memories that are made and used in every-day life are typically not, such as names, images, addresses etc., limiting the external validity of research into this field - A limitation of the MSM is that there is evidence that suggests there is more than one STM store. In the KF case study (by Shallice and Warrington), KF is a client who has a amnesia, which makes him struggle to encode digits into his STM when they were read out loud to him, however, when he read them to himself he was more successful, further studies of KF and others also showed that there could be another store for non-verbal sounds (noises), therefore suggesting that the MSM is inaccurate for claiming that there is only one STM store for processing all different types of information
- A strength of the model is that there is evidence to support the existence and importance of the rehearsal loop, in the HM case study he suffers from epilepsy after falling off of his bike as a kid and cracked his head open, in attempt to cure it, William Scoville removed his hippocampus, but instead this stopped his ability to produce new memories, the hippocampus is the part of the brain where the rehearsal loop is carried out, HM developed anterograde amnesia, which is a disability to produce new memories and retain new information after diagnosed, not only does this support that the rehearsal loop has the role of transferring information into the LTM, but it also supports that the STM and LTM are distinct.
However, HM’s star tracing test counters this, as he was able to improve his tracing abilities each time he was tasked to attempt to trace the star, however he didn’t remember doing it, this suggests that he was able to improve his procedural memory without knowing, which implies that the MSM does not account for the different types of LTM and is therefore limited.
Types of Long Term Memory - A01
Tulving was the first cognitive psychologist to claim that the MSM was too simplistic regarding the LTM, he proposed that there were three types of LTM; episodic, semantic and procedural.
Episodic memory refers to our ability to recall events/memories from our lives, this has often been likened to ‘a diary’, an account of our personal experiences (eg. a trip to the dentist or a holiday), these memories are time-stamped and they are stored with a recollection of how they relate to eachother in time, they also involve several elements (people, places that all make up one memory), we are also conscious when we recall them even though it is still quick, we acknowledge that we are searching to retrieve them.
Semantic memories refer to our shared knowledge of the world, and has been likened to an encyclopedia and dictionary, these memories involve knowledge such things, like tastes of foods, as well as knowing the meanings of words, and an impressive number of concepts, such as ‘animals’ and ‘love’, these are not time-stamped and we don’t normally remember when we learnt them compared to episodic memories, however they hold a lot of material and Tulving claims they are less vulnerable to distortion and forgetting.
Procedural memories are our memories for skills and actions (how we do things), we can recall these without conscious awareness (eventually), such as driving, our abilities become more automatic with practice, they are sometimes difficult to explain to someone else and can make a task more difficult when doing so.
Types of Long Term Memory - A03
- There is clinical evidence from the cases of HM and Clive Wearing to suggest that Tulving’s claim that there were multiple types of LTM, both men has severely impaired episodic memories, however both of their semantic memories and procedural memories were intact, they both remained knowledgeable of the world and were able to understand the concepts of things, as well as remaining able to walk and speak, Clive Wearing was even able to sing, play piano and read music after previously being a professional musician, therefore supporting that there are multiple distinct types of LTM and that they can continue to function even when one is impaired.
However, clinical studies that involve studying people with brain injuries lack control and therefore internal validity, as the injuries and damage they endure are almost always unexpected and the researcher has no way of controlling what happened to them before or during their injury, as well as not having any knowledge of how their memory was before, this lack of control therefore limits what clinical studies can tell us about different types of LTM. - A limitation is that there are conflicting research findings that link types of LTM to areas of the brain, Buckner and Peterson (1996) reviewed evidence regarding the location of episodic ad semantic memory, where they concluded that semantic memory is located in the left side of the pre-frontal cortex (PFC) and episodic is in the right, however other research links the left side of the PFC to the encoding of episodic memories and the right side with episodic retrieval, therefore challenging any neurophysiological evidence for support as there is poor agreement on the location of types being based
- A strength is the real-life application of psychologists understanding the different types of LTM, they are able tp help people with memory problems, such as people struggling with their episodic memory as they get older, Belleville et al. (2006) devised an intervention to help improve older people’s episodic memory and then when tested, the trained ppts performed better on an episodic memory test than a control group, suggesting that understanding the different types of LTM is useful in real-life as it can help develop specific treatments
The Working Memory Model - (A01)
- Baddeley and Hitch (1974) proposed the model as an explanation for how the STM is organised and how it functions
- the central executive has a supervisory role in the model and monitors incoming data, focuses and divides our limited attention and allocated subsystems to tasks, very limited processing capacity and does not store information
- the phonological loop deals with auditory information and preserves the order in which information arrives, the phonological store stores words you hear and the articulatory process allows maintenance rehearsal, the capacity is said to be 2 seconds
- the visuo-spatial sketchpad stores visual and spatial information when required, it has limited capacity of around 3/4 objects according to Baddeley, Logie (1995) later divided it into two subsystems known as the visual cache which stores data and the inner scribe which records the arrangement of objects in the visual field
- the episodic buffer was added to the model by Baddeley in 2000 and it is a temporary store for information, integrating the visual, spatial, and verbal information processed by the other stores and maintaining a sense of time sequencing essentially recording episodes, it can be seen as the storage compartment for the central executive and it has a limited capacity of about 4 chunks (Baddeley 2012), the episodic buffer connects the working memory model to long term memory and wider cognitive processes such as perception
The Working Memory Model (A03)
- a strength is support from Shallice and Warrington (1970) case study on a patient called KF who had a brain injury and then had poor STM ability for auditory information but he could process visual information normally, his immediate recall of letters and digits was better when he read them rather then hearing them, KF;s phonological loop was damaged but his visuo-spatial sketchpad was intact, therefore the finding strongly supports the existence of the separate visual and auditory memory stores
However, it is unknown whether KF had other cognitive impairments which may have affected his performance on memory tasks, his brain injury was after a motorbike accident and while his brain was injured, the trauma could have affected his cognitive performance, therefore challenging the evidence that comes from clinical studies as people with brain injuries may also have other affected systems - a strength is Baddeley et al.’s study (1975) on dual-task performance, participants carried out a visual and verbal task at the same time and their performance was similar to when they performed the tasks separately, however when both tasks were visual or both tasks were verbal their performance worsened significantly, this is because visual tasks occupy the visuo-spatial sketchpad and verbal tasks occupy the phonological loop and each sub-system can only successfully be occupies at once in order for the task to be performed well, when the tasks carried out were both visual/verbal they compete for the same sub-system whereas there is no competition when the tasks occupy different subsystems, therefore the dual-task study supports that the systems are distinct and that visual and verbal tasks have separate subsystems
- a limitation of the model is that there is a lack of clarity over the nature of the central executive, Baddeley himself recognised it and said “the central executive is the most important but least understood component of the working model”, there is a lack of clarification over the actual role of the central executive as ‘attention’ is very simple, some psychologists believe that it may consist of separate subcomponents, therefore the central executive is an unsatisfactory component and it challenges the integrity of the model
Explanations for Forgetting - Interference (A01)
- interference is when two pieces on information disrupt eachother and results in forgetting one or both or a distortion of memory
- interference is proposed as an explanation for forgetting from the LTM as we can’t get access to them even though they are available, interference makes it harder for us to locate them and can therefore be experienced as forgetting
- proactive interference occurs when an older memory interferes with a newer one, such as a teacher not remembering names in their new class since they have had to remember so many before
- retroactive interference occurs when a newer memory interferences with an older one, for example a teacher has learned so many new names this year that they forget some of the ones they learnt last year
- both types of interference are worse when the memories/information is similar (McGeoch and McDonald 1931), they studies retroactive interference by changing the similarity between two sets of material, ppts had to learn a list of 10 words until they could remember it with 100% accuracy, they were then given new lists, synonyms, antonyms, words unrelated to the originals, consonant syllables, three digit numbers, and no new list (control), when ppts were asked to recall the original list the worse recall was from the synonyms condition and the best other than control was the numbers condition, showing that interference was the strongest when the memories are similar
- this could be because previously stored information makes new similar information harder to store, or it could be because newer similar information overwrites previous similar information
Explanations for Forgetting - Interference (A03)
- a strength is that there is evidence of interference effects in every day life, Baddeley and Hitch (1977) carried out a study where they asked rugby players to recall the names of teams they had played against during the season, the players all played the same number of games however some missed some due to injury or schedule, the players who played the most games had the worst recall of team names (most interference for memory), this study shows that interference can have effects on real-life situations therefore increasing its external validity
- a limitation is that most of the studies (including above) are artificial tasks usually involving a list of words which is not reflective of normal tasks people endure every day, interference to occur the memories need to be similar which is possible in everyday life but it is unusual, the study was designed specifically to measure interference and controlled with ideal conditions created, however a task like that is rare and therefore suggesting that other explanations for forgetting may be more suitable for explaining everyday forgetting as interference is not typical (retrieval failure?)
- a limitation is that interference can be overcome by using hints and clues to help remember something, Tulving and Psotka (1971) gave participants lists of words organised into categories one at a time, recall for the first list was 70% but as the lists went on recall worsened (interference), at the end of the procedure the participants were given another recall test with cues for the list categories, recall rose to 70% again, suggesting that interference causes temporary loss of accessibility to material that is still in the LTM, which isn’t predicted by the interference theory
Explanations for Forgetting - Retrieval Failure (A01)
- people forge things because of insufficient cues, when memory is initially encoded into memory associated cues are stored at the same time, if the cues are not available at the same time as recall, information may appear forgotten, however it is retrieval failure - not being able to access the memories that are there
- Tulving (1983) reviewed research and found a consistent pattern of cues needing to present at encoding and present at retrieval in order to be helpful in remembering, this is the encoding specificity principle, if cues at encoding and retrieval are different then some forgetting may occur, some cues are encoded at the time of learning in a meaningful way, where information an details about the memory will also be recalled, meaning cues are also used in many mnemonic techniques (memory techniques) as well as some cues being non-meaningful
- context-depending forgetting is when recall depends on an external cue (eg. location) and state-dependent forgetting is when recall depends on an internal cue (eg. an emotion)
- Godden and Baddeley (1975) researched context-depending forgetting with a study on deep-sea divers where they learned a list of words either underwater or over water, the four conditions were: learn on land - recall on land, learn on land - recall underwater, learn underwater - recall on land, learn underwater - recall underwater, in the conditions where the learning and recall environment were the same the findings were the same, recall accuracy was 40% lower in the conditions where the environments did not match, they concluded that forgetting occurred as a result of the environments on recall and learning not matching which lead to retrieval failure
- Carter and Cassaday (1998) researcher state-dependent forgetting by giving participants antihistamine drugs (for hay fever) which had a mildly sedating effect on them so they were slightly drowsy and therefore had a different internal physiological state to normally being awake and alert, the participants had lists of words and passages of writing to learn in both internal states, the conditions were: learn on drug - recall on drug, learn on drug - recall off drug, learn off drug - recall on drug, learn off drug - recall off drug, the performance on the memory test was significantly lower for the conditions where the internal state of recall and learning did not match, suggesting that when the cues are absent there is more forgetting (as a result of retrieval failure)
Explanations for Forgetting - Retrieval Failure (A03)
- a strength is that understanding retrieval failure can have real life application in helping people to overcome forgetting in everyday situations, although cues do not have a very strong effect on forgetting, Baddeley suggested that it is still worth utilising them, an example of this is when someone is revising for a test, they can purposely revise in the same room/environment as the place that they will take the test in order to create cues that will be available in the test, meaning that they will be more likely to be able to recall information as there will be no forgetting effect of context-state forgetting, this shows that research into retrieval failure can be useful to help us put strategies in place to help us remember in real-life situations
- the two studies from Godden and Baddeley and Carter and Cassaday both support the relevance of encoding information in the same state as recalling it and how that has a significant effect on recall accuracy, and that a lack of the relevant cues can lead to context-dependent forgetting and state-dependent forgetting in real-life situations, Eysenck and Keane (2010) argues that retrieval failure is the main reason for forgetting from LTM
however, Baddeley (1997) argued that context effects are not very strong as environments don’t tend to be very different, as in the deep-sea divers study the environments were significantly different whereas in every-day life two rooms (for example) do not tend to be as different as that, potentially suggesting that the study lacked external validity and that retrieval failure due to a lack of context cues may not be a strong way to explain everyday forgetting - a limitation is that context cues may depend on the type of memory being tested, Godden and Baddeley replicated their test in 1980 but instead tested their recognition by seeing if they could recognise a word in a list after having it read to them in the different environments, they found that the recognition accuracy was the same in all four conditions, suggesting that retrieval failure is a limited explanation for forgetting as it only applies to remembering/recalling information rather than recognising it
Factors Affecting the Accuracy of Eyewitness Testimonies - Misleading Information (A01)
Leading Questions
- when asking questions sometimes their wording can lead a person to give a certain answer, which becomes an issue in eyewitness testimonies as the police questions may direct the witness’ answer
- Loftus and Palmer (1974) had 45 participants watch a clip of a car crash and then answer questions about it after, within the questions was a leading question which had one of five words in it depending on the condition asking how fast they thought the car was going; contacted, collided, bumped, hit, smashed, they found that the mean estimate of the group with ‘collided’ was 31.8 mph and the group with ‘smashed’ was 40.5 mph, suggesting that the leading question biased the eyewitness’ recall of events
- the response-biased explanation states that the wording of a question does not have an effect on a person’s actual memories but effects how they decide to answer a question; when the question said ‘smashed’ it influenced them to answer a faster speed, Loftus and Palmer (1974) later conducted a second study where they asked the same participants if there had been broken glass at the accident scene, those who had the word ‘smashed’ claimed to see broken glass and those who had ‘hit’ didn’t, their findings support the substitution explanation that claims the wording of a question can in fact change the actual memory a person has since there was no glass, the critical verb altered their memory of the accident
Post-Event Discussion
-Gabbert et al. (2003) had participants in pairs who each watched a clip of the same crime but from different points of view, one POV showed the title of a book a woman carried out, after watching the video they had a discussion about the video and then completed an individual recall test, researchers found that 71% of participants recalled aspects of the crime that they had not seen on their own video but had picked up in the discussion, a control group carried out the same procedure but with no discussion and their recall test showed 0% recall of details from the other person’s clip, this was evidence of memory conformity
- an explanation for how post-event discussion effects eyewitness testimonies is memory contamination, which is when witnesses to a crime discuss it with eachother and their memories of it become contaminated (altered, distorted) because they combine information from other witnesses with their own memories, another explanation is memory conformity, which Gabbert et al concluded is when witnesses often go along with each other to win social approval or because they genuinely believe that the other person is right and they are wrong, unlike with memory contamination where the memory is actually changed
Factors Affecting the Accuracy of Eyewitness Testimonies - Misleading Information (A03)
- a strength of research into misleading information is that is has important practical uses in the justice system, the consequences of inaccurate eyewitness testimonies can be fatal, Loftus (1975) believed that leading questions can have such a distorting effect on memories that police need to be careful in how they word their questions during interviews, psychologists are sometimes asked to act as expert witnesses in court and explain the limits of EWT to juries, therefore suggesting that psychologists can help to improve the legal system works especially to protect innocent people from being falsely convicted as a result of unreliable EWT
however, the research on EWT may be faulted for practical applications, as Loftus and Palmer’s participants watched a video of an accident rather than actual experiencing witnessing one, which is a lot less distressing and realistic, Foster et al (1994) pointed out that eyewitnesses memories of crimes have more important consequences in the real world whereas participants matter less as they were less motivated to be accurate and felt less pressure, suggesting that researchers such as Loftus were too pessimistic and EWT may be more dependable that they suggested - a limitation of the substitution explanation is that EWT are more accurate for some aspects of an event than others, Sutherland and Hayne (2001) showed participants a video clip and when later asked misleading questions their recall was more accurate for the central details of the event rather than the peripheral ones, suggesting that the participants attention was focused on the central features and these memories were fairly resistant to misleading information, this suggests that original memories for central details were not distorted and survived, which in not predicted by the substitution explanation
- a limitation of the memory conformity explanation is that there is evidence that post-event discussion actually alters EWT, Skagerberg and Wright (2008) showed participants one of two film clips, one where the muggers hair was dark brown and one light brown, participants discussed the clip in pairs having seen different clips, and when asked about it later they often answered with a blend of what they had seen and what they had heard in the discussion, such as answering that the mugger had ‘medium brown’ hair rather than dark or light, suggesting that the memory itself has been distorted through contamination by misleading information rather then memory conformity, since they didn’t answer with what they had heard, but a blend
Factors Affecting the Accuracy of Eyewitness Testimonies - Anxiety (A01)
- anxiety has both mental and physical effects but it is unclear whether it has an effect of better or worse recall on EWT
Weapon Focus (worse recall)
- anxiety creates physiological arousal in the body which prevents us from paying attention to important cues making recall worse, the presence of a weapon creates anxiety and makes people draw their attention to it, leading to focus on the weapon and reducing the witness’ recall for the other details of the event
- Johnson and Scott (1976) had participants believe they were taking part in a lab study and had them waiting out in a waiting room, in the low-anxiety condition they heard a casual conversation happen in the next room then saw a man walk past them with a pen and grease on his hand, in the high-anxiety condition they heard a heated argument and breaking glass then saw a man walking out holding a bloody knife, the participants later picked the man they had seen out of 50 photos, 49% of the low-anxiety condition picked out the correct photo and 33% of the high-anxiety condition picked out the correct man
- the tunnel theory of memory argues that people have enhanced memory for central events therefore weapon focus as a result of anxiety can affect recall
Fight or Flight (increases recall)
- witnessing a stressful event creates physiological arousal in the body which triggers the fight or flight response which increases a person’s alertness which improves the memory of the event as we become more aware of cues in the situation
- Yuille and Cutshall (1986) studied an actual shooting in a gun shop in Canada Vancouver where the shop owner was shot, there were 21 witnesses and 13 of them were interviewed and used in the study, they were interviewed 4/5 months after the incident and recall accuracy was assessed by the number of details about the shooting they recalled compared to their original EWT statements, witnesses also ranked how stressed they felt at the time on a 7-point scale and asked if it had any emotional effects on them, the witnesses overall had very good recall accuracy of the details of the event however the ones who rated themselves higher on the stress scale had 88% more recall accuracy than the lower rating witnesses who had 75% recall accuracy, this suggests that anxiety that does not have a detrimental effect on the accuracy of EWT and can sometimes even enhance it
Explaining Contradiction
- Yerkes and Dodson (1908) explained that the relationship between arousal and performance looked like an inverted U
- Deffenbacher (1983) reviewed 21 studies of EWT and explained the relationship using Yerkes and Dodson’s law, he explained that when we witness a crime/accident we get aroused mentally (anxiety) and physiologically (fight or flight response), lower levels or arousal produce lower levels or recall accuracy and then as we get more aroused recall accuracy increases, however there is a point of optimal level of anxiety were we reach our maximum accuracy and after that point in reached further increases of arousal leads to decreasing recall accuracy
Factors Affecting the Accuracy of an Eyewitness Testimony - Anxiety (A03)
- a strength is evidence supporting that anxiety has a negative effect on recall, Valentine and Mesout (2009) used an objective measure (heart rate) to divide participants into low and high anxiety groups when going into the Horror Labyrinth at London Dungeon, when in the experience the participants experienced scares such as darkness, screams, jump-scares and gory models, the visitors were offered reduced entrance fees if they agreed to fill out questionnaires on the anxiety they felt during, their task was to describe the person (actor) they encountered in the Labyrinth, researchers found that those in the high-anxiety group recalled less details that those in the low, they also found that 17% of the high anxiety group identified the actor in a line-up whereas 75% of the low group did, suggesting that high levels of anxiety does have a negative effect on immediate eyewitness recall of a stressful event
- there is also evidence to support that anxiety can have a positive effect on recall, Christianson and Hubinette (1993) interviewed 58 witnesses to actual bank robberies in Sweden, some were directly involved (bank workers) and some were not (like bystanders), the researchers assumed that those directly involved would experience more anxiety, all witnesses showed accurate recall of over 75% however those the direct victims’ was higher, these real life studies show that anxiety does not reduce the accuracy of recall for eyewitnesses and may even enhance it
however, Christianson and Hubnette interviewed their participants 4-15 months after the incidents and therefore had no control over what they did in between times (eg. post-event discussion), the effects of anxiety may have been overwhelmed by these other factors and were impossible to assess by the time they were interviewed, therefore limiting the internal validity of their study as it was possible that the lack of confounding variables were responsible for the findings - a limitation is that Johnson and Scott’s study may have not been assessing anxiety but unusualness, Pickel (1998) conducted an experiment using scissors, a wallet, a handgun or a raw chicken as hand-held items in a hairdressers waiting room video, where scissors would be high anxiety but low unusualness, eyewitness recall accuracy was significantly lower in the high unusualness conditions (chicken and gun), suggesting that the weapon focus effect is actually due to the unusualness rather than the anxiety/threat and therefore tells us nothing specifically about the effects on anxiety on EWT
Improving the Accuracy of EWT - Cognitive Interview (A01)
- Fisher and Geiselman (1992) argues that eyewitness testimonies could be improved in police used better techniques when interviewing witnesses, they recommended such techniques based on our psychological understanding of how memory works and collectively these techniques are called the cognitive interview as it has a foundation in cognitive psychology, the four stages are
1. Report everything - the witness is encouraged to recall and state every detail about the event even if they think it may be irrelevant or are not confident, seemingly trivial memories may be important and they can also trigger them to remember other details
2. reinstate the context - the witness should re-visit the crime scene in their minds and imagine the environment as well as the emotions they felt, this is related to context-dependent forgetting
3. reverse the order - witnesses should report the events of the crime in a different order to how they happened (eg. from last to first) in order to avoid their expectations of what happened next interfere with their real answers, it also prevents dishonesty as it is harder to produce untruthful content if they have to reverse it
4. change perspective - the witness recalls the events from the crime from a different perspective (eg. the offender or victim) in order to prevent them from letting their expectations alter their memory recall as well as the effect on schema, a schema for example of going into a shop may influence their recall of what actually happens normally rather then the actual crime, - Fisher et al. (1987) introduced some new elements to the cognitive interview that focus on the social dynamics of the interaction, such as the interviewer needing to know when to hold eye-contact, the enhanced cognitive interview also includes ideas such as reducing the witness’ anxiety, minimising distractions and getting them to speak slowly and clearly and asking open-ended questions
Improving the Accuracy of EWT - Cognitive Interview (A03)
- a strength of the cognitive interview is that there is evidence that it works, Kohnken et al. (1999) conducted a met-analysis of 55 cases where the cognitive interview was used compared to normal police interviews, the CI cases gave a 41% increase of accurate information recalled compared to the standard one, only four studies in the analysis showed no difference, this shows that the CI is effective and useful for helping eyewitnesses recall information stored in the memory that is less accessible
however, Kohnken et al. also found an increase in inaccurate information being recalled, particularly in the enhanced cognitive interview, cognitive interviews may sacrifice quality of recalled information for quantity, meaning police should treat evidence from EWT with caution - a limitation of the CI is that not all components are equally useful or effective, Milne and Bull (2002) found that each of the four techniques used alone produced a more accurate testimony than the standard police interview, however a combination of report everything and reinstate the context produced better recall than any of the other elements of combinations of them, this confirmed police suspicions that not all of the elements are the same level of usefulness, therefore casting some doubt on the credibility of the overall cognitive interview
- another limitation is that it is more time and effort consuming than normal police interviews, time to train the police officers to learn the techniques used in the interview is much longer which is not always available and in some cases there are limited resources for only a few hours (Kebbell and Wagstaff 1997), therefore suggesting it may be an unrealistic method for police officers to use as they will be more reluctant to endure the long training and therefore it may be more important to focus on just a few key elements
this can lead to economic implications as well
