memory studies and evaluation

• Coding research (Baddeley 1966)


  -gave different lists of words to 4 groups of ppts to remember

  -1; acoustically similar words 2; acoustically dissimilar words 3; semantically similar 4; semantically dissimilar words

  -found immediate recall worse with acoustically similar so STM coding is acoustic, after 20 mins recall worse with semantically similar so LTM coding is semantic
• Coding research evaluation


  -strength, identified separate memory stores: later research showed some exceptions to Baddely's findings, but STM acoustic + LTM semantic still true, important in the development of the MSM model

  -limitation, used artificial stimuli: words used had no personal meaning to ppts so tells little about coding in other kinds of memory tasks, ppl use semantic for processing more meaningful information even in STM, suggests findings have limited application
• Capacity research - digit span (Jacobs 1887)

  -researcher reads 4 digits and ppt recalls them out loud in correct order

  -if correct then researcher reads out 5 digits and so on until ppt can't recall in correct order

  -this is the ppts digit span

  -Jacobs found that average span for digits was 9.3 items and for letters was 7.3
• Capacity research - digit span evaluation

  -strength, study has been replicated: this is an old study so maybe less control of confounding variables, but findings confirmed in later controlled studies, shows Jacobs' study is a valid measure of STM digit span
• Capacity research - memory span and chunking (Miller 1956)


  -Miller observed everyday practice and noted that things come in sevens; days of the week, deadly sins

  -found the span of STM is about 7 items (+/- 2) but can be increased by chunking (grouping sets of digits or letters into units or chunks)
• Capacity research - memory span and chunking evaluation

  -limitation, may overestimate STM capacity: Cowan (2001) reviewed other research, concluded that STM capacity is only 4 (+/- 1), suggests the lower end of Miller's estimate (5) is more appropriate than 7
• SR duration research (Sperling 1960)

  -tested the sensory register, ppts saw a 3x4 grid of digits and letters for 50 milliseconds

  -they were either asked to record all 12 items or too they would hear a tone after the exposure and to only record the indicated row (top, middle, or bottom)

  -when reporting the whole thing recall was poorer (average 5 recalled, 42%) and when reporting only one row recall was better (average 3 recalled, 75%)

  -supports limited duration of SR
• STM duration research (Peterson and Peterson 1959)


  -tested 24 students in 8 trials

  -in each trial they were given a consonant syllable (e.g., YCG) and a 3 digit number

  -they counted backwards from the number until told to stop, prevented mental rehearsal of the constant syllable

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• STM duration research evaluation

  -limitation, stimulus material was artificial/meaningless: recalling consonant syllables doesn't reflect most everyday memory activities where what we are trying to remember is meaningful, means the study lacked external validity
• LTM duration research (Bahrik et al. 1975)


  -studied 392 american ppts aged 17-74, high school yearbooks obtained and recall was tested in 2 ways: (1) photo-recognition test of 50 photos, some from the yearbooks, (2) free recall test, ppts recalled names from their class

  -photo recognition: ppts tested within 15yrs of graduating 90% accurate, recall declined to 70% after 48yrs

  -free recall: 60% after 15yrs, dropped to 30% after 48yrs

  -shows LTM can last up to a lifetime for some material
• LTM duration research evaluation

  -strength, high external validity: researchers investigated meaningful memories, studies on LTM conducted with meaningless information had lower recall rates, Bahrick et al.'s findings reflect a more 'real' estimate of LTM duration
• who designed the multi-store model of memory?

  Atkinson and Shiffrin (1968)
• MSM evaluation - strengths

  -supporting evidence, other studies show STM and LTM are different: Baddeley (1966) found we tend to mix up words that sound similar when using STM but mix up words with similar meanings when using LTM, supports MSM claims as study shows STM and LTM are separate memory stores, COUNTERPOINT: many studies that support MSM use meaningless materials like digits or words instead of useful ones like names or places, suggests MSM may not be a valid model of how memory works everyday when remembering more meaningful information
• MSM evaluation - limitations

  -some evidence suggests there is more than one STM store: Shallice and Warrington (1970) studied KF who had amnesia, his recall for digits was poor when they were read to him but better when he read them to himself, suggests MSM is wrong to claim there is just one STM store processing different types of information (e.g, visual and auditory)

  -prolonged rehearsal is not needed for transfer to LTM: MSM says more rehearsal means information is more likely to transfer to LTM but Craik and Watkins (1973) found the type of rehearsal matters more than the amount, elaborative rehearsal (linking to pre-existing knowledge) is necessary for LTM and information can be transferred without prolonged rehearsal, suggests MSM doesn't fully explain how LTM is achieved
• types of LTM (Tulving 1985)

  -realised MSM view of LTM was too simplistic and proposed there were 3 LTM stores; episodic, semantic, and procedural
• types of LTM evaluation - strengths

  -support from clinical evidence, HM and Clive Wearing: both of the men suffered brain damage which impaired their episodic memory but their semantic memories were relatively unaffected and their procedural memories remained intact, evidence supports Tulving's view that the LTM is made up of different memory stores - one store can be damaged whilst the others remain intact, COUNTERPOINT: studying people with brain injuries helps researchers to understand how memory works but clinical studies lack control of variables, researchers can't control experiences or have any knowledge of the individual's memory prior to injury so cannot judge how much it has been damaged, this limits what clinical studies can tell us about LTM

  -real-world application, understanding LTM types allows psychologists to help people with memory problems: as people age they suffer memory loss but research shows this is specific to episodic memory - it's harder to recall recent personal events though past episodic memories remain intact, Belleville et al. (2007) was able to devise an effective intervention that improved episodic memories in old people, this shows that distinguishing between types of LTM allows the development of specific treatments
• types of LTM evaluation - limitations

  -conflicting neuroimaging evidence, there ae conflicting research findings linking types of LTM to areas of the brain: Buckner and Petersen (1996) reviewed evidence of the location of semantic and episodic memory, concluded that semantic is on the left of the prefrontal cortex and episodic is on the left, however Tulving et al.'s research (1994) proposes the opposite, this challenges neurophysiological evidence to support types of memory as agreement on where the types are located is poor
• who designed the working memory model? which aspect of memory does it focus on?

  -Baddeley and Hitch (1974)

  -focuses on how STM both functions and is organised

  -concerned with the 'mental space' that is active when we are temporarily storing and manipulating information
• WMM evaluation - strengths

  -clinical evidence, support from Shallice and Warrington's case study of KF (1970): KF suffered a brain injury and afterwards had poor STM ability for auditory information but could process visual information normally, his phonological loops damaged but his visuo-spatial sketchpad was intact, strongly supports the existence of separate visual and acoustic memory stores, COUNTERPOINT: unclear whether KF had other cognitive impairments which may have affected his performance tasks, his injury was caused by a motorcycle accident and the trauma could have also impacted his cognitive performance aside from the brain injury, this challenges evidence from clinical studies of people with brain injuries that may have effected multiple systems

  -studies of dual-task performance support the separate existence of the visuo-spatial sketchpad: when Baddeley et al.'s (1975) ppts carried out visual and verbal tasks at the same time their performance was similar to when they carried them out separately, but when both tasks were visual performance on both declined greatly, this is because both visual tasks competed for the same slave subsystem
• WMM evaluation - limitations

  -there is lack of clarity over the nature of the central executive: the CE is the least understood component of the WMM and needs to be more clearly specified than just being simply 'attention', for instance some psychologists believe it may consist of separate subcomponents, this means the CE is an unsatisfactory component which challenges the integrity of the WMM
• interference theory research - effects of similarity (McGeoch and McDonald 1931)

  -ppts had to learn a list of 10 words till they could remember them with 100% accuracy, they then learned a new list

  -there were 6 groups who had to learn different types of new lists: (1) synonyms of the originals, (2) antonyms of the originals, (3) words unrelated to the originals, (4) consonant syllables, (5) 3 digit numbers, (6) no new list - control condition

  -when asked to recall the original list., ppts with the synonyms (similar material) recalled the least, showing interference is stronger when memories are similar
• interference theory evaluation - strengths

  -real-world interference, there's evidence of interference effects in real life: Baddeley and Hitch asked rugby players to recall the teams they had played against during a season, they all played for the same time interval (one season) yet some players had missed some matches. the players who had played the most games (most memory interference) had the poorest recall, showing interference can operate in some real-world situations and increasing the theory's validity

  -support from drug studies, evidence of retrograde facilitation: Coenen and Luijtelaar (1977) gave ppts a list of words and later asked them to recall the list, they found that when a list was learned under the influence of diazepam recall one week later was poor compared to a placebo control group, but when the list was learned and the drug was taken afterwards the recall was better than the placebo, the drug improved recall of material learned beforehand as it prevents information reaching the parts of the brain responsible for processing memories and stops it interfering with pre-stored information, findings show forgetting can be caused by interference - reducing interference reduces forgetting
• interference theory evaluation - limitations

  -interference is temporary and can be overcome by using cues: Tulving and Psotka (1971) gave ppts lists of words (one at a time) organised into categories (ppts didnt know the categories), recall averaged 70% for first list and dropped as ppts learnt additional lists (proactive interference), at th end the ppts were tested again but with cues as they were told of each category and recall rose to 70% again, showing interference causes a temporary loss of accessibility to material still in the LTM which is not predicted by interference theory.
• retrieval failure - the encoding specificity principle, ESP (Tulving 1983)


  -reviewed research into retrieval failure and found a pattern

  -ESP states that a helpful cue has to be both (1) present at encoding and (2) present at retrieval, so if the cues available at encoding and retrieval are different or absent then there will be some forgetting

  -some cues are encoded in a meaningful way, for instance STM, and are used in many mnemonic techniques

  -other cues can be encoded and non-meaningful such as external (place or weather) and internal (emotion or being drunk)
• retrieval failure - context-dependent forgetting research (Godden and Baddeley 1975)


  -studied deep-sea divers who work underwater to see what effect training on land had on their work underwater

  -they learned a list of words either on land or underwater and then were asked to recall them either on land or underwater

  -there were 4 conditions: (1) learn and recall on land, (2) learn on land and recall underwater, (3) learn underwater and recall on land, (4) learn and recall underwater

  -accurate recall was 40% lower in non-matching conditions than in the matching conditions

  -Godden and Baddeley concluded that the external cues available at learning were different to the ones available at recall - leading to retrieval failure
• retrieval failure - state-dependent forgetting research (Carter and Cassaday 1998)


  -gave antihistamine drugs to their ppts, they had a mild sedative effect that made the ppts drowsy and created an internal state different from the 'normal' state of being awake/alert - the ppts then had to learn lists of words and passages of prose, then recall the information

  -there were four condition: (1) learn and recall on drug, (2) learn on drug and recall not on drug, (3) learn not on drug and recall on drug, (4) learn and recall not on drug

  -in conditions with a mismatch between internal state at learning and recall, recall was significantly worse

  -so when cues are absent there is more forgetting
• retrieval failure evaluation - strengths

  -there is research support for this theory: studies by Godden + Baddeley and Carter + Cassidy are useful as they show that lack of relevant cues at recall can lead to context-dependent and state-dependent forgetting in everyday life, Eysenck and Keane (2010) even argued retrieval failure was the main reason for forgetting from the LTM, this evidence shows how retrieval failure occurs in real world situations and in highly controlled lab conditions, COUNTERPOINT: Baddeley (1997) argues context effects are not very strong and different contexts have to be vastly different before an effect is seen (eg., on land and underwater), learning something in one room and recalling it in another is unlikely to result in much forgetting as the environments aren't different enough, this means retrieval failure caused by lack of contextual cues may not explain much for everyday forgetting
• retrieval failure evaluation - limitations

  -recall VS recognition, context effects may depended substantially on the type of memory being tested: Godden and Baddeley (1980) replicated their underwater experiment with a recognition test instead of recall, ppts said whether they recognised words read to them from a list instead of recalling it themselves, when recognition was tested there wasn't a context-dependent effect and performance was the same in all conditions, suggesting retrieval failure is a limited explanation for forgetting as it only applies when recall of information is needed rather than recognition
• misleading information - leading questions research (Loftus and Palmer 1974)


  -45 students watched film clips of car accidents and were then asked questions about the accident

  -critical question: 'about how fast were the cars going when they ... eachother?', 5 groups of ppts were given a different verb in the critical question: hit, contacted, bumped, collided, smashed.

  -the mean estimated speed when the verb 'contacted' was used was lower than when 'smashed' was used, meaning the leading question biased the witnesses recall of the event
• misleading information - substitution explanation research (Loftus and Palmer 1974)

  -2nd experiment that supported the substitution explanation's idea the wording of a leading question changed the ppts memory of the film clip

  -this was demonstrated as ppts who originally heard 'smashed' were more likely to report seeing broken glass (there was none) than those who heard 'hit'

  -the critical verb altered their memory of the incident
• misleading information - post-event discussion research (Gabbert et al. 2003)


  -studied ppts in pairs, each watched a video of the same crime from different points of view, so each ppt could see elements the other could not

  -the ppts then discussed what they had seen before completing a test of recall individually

  -found that 71% of ppts wrongly recalled aspects of the event that they had not witnessed but had picked up in discussion, the corresponding figure in a control group where there was no discussion, was zero

  -this was evidence of memory conformity
• misleading information evaluation - strengths

  -real world application, research into misleading information has practical uses in the criminal justice system: leading questions can distort memory and police officers need to be very careful of the phrasing of their questions to eye witnesses, psychologists sometimes act as expert witnesses in court trials to explain the limits of EWT to judges, showing how psychologist can improve the legal system by protecting innocent people from faulty convictions caused by unreliable EWT, COUNTERPOINT, the practical applications of EWT are effected by research issues: Foster et al. pointed out that what witnesses remember has important consequences in the real world but matter less in research so Loftus and Palmer's ppts were less motivated to be accurate, suggesting researchers like Loftus are too pessimistic about misleading information effects and EWT could be more dependable than studies suggest
• misleading information evaluation - limitations

  -evidence against substitution, EWT is more accurate in some aspects of an event than for others: Sutherland and Hayne (2001) showed ppts a video clip and when asked misleading questions their recall was more accurate for central details than it was for peripheral, ppts attention was focused on central features of the event and these memories were more resistant to misleading information, suggesting the original memories of central details were not distorted which was not predicted by the substitution explanation

  -evidence challenging memory conformity: research shows post-event discussion actually alters EWT: Skagerberg and Wright (2008) showed ppts film clips, in one a muggers hair was dark brown and in the other it was light brown, after ppts discussed the clips in pairs they often reported a 'blend' of what they had seen and what their partner had told them (e.g., medium brown rather than light or dark), suggesting the memory itself was distorted through contamination by post-event discussion rather than as a result of memory conformity
• anxiety - negative effect on recall research (Johnson and Scott 1976)


  -ppts believed they were taking part in a lab study

  -while seated in a waiting room ppts in the low anxiety condition heard a casual conversation in the next room and then saw a man leave carrying a pen with grease on his hands, in the high anxiety condition ppts heard a heated argument and the sound of breaking glass followed by a man leading holding a knife covered in blood

  - ppts later picked the man out of 50 photos, in the low anxiety condition 49% of ppts identified him correctly and in the high anxiety condition only 33% correctly identified the man

  -the tunnel theory suggest people have an enhanced memory for central events and weapon focus as a result of anxiety can have this effect
• anxiety - positive effect on recall research (Yuille and Cutshall 1986)


  -conducted a study of an actual shooting in a gun shop where the owner shot a thief dead, there 21 witnesses and 13 took part in the study

  -ppts interviewed 4-5 months after the event, the interviews were compared to the original police interviews and accuracy was determined by the number of details reported in each account

  -witnesses were also asked to rate on a 7-point scale how stressed they felt at the time

  -ppts who reported the highest stress levels were the most accurate, suggesting anxiety doesn't have a detrimental effect on EWT accuracy in a real world context and could potentially enhance the accuracy
• anxiety evaluation - strengths

  -support for negative effects on recall accuracy: Valentine and Mesout (2009) used an objective measure (heart rate) to divide ppts into high anxiety and low anxiety groups, the ppts with higher anxiety found it disrupted their ability to recall details about the actor in the London Dungeon's labyrinth, suggesting a high level of anxiety has a negative effect on immediate eyewitness recall of stressful events

  -support for positive effects on recall accuracy: Christianson and Hubinette interviewed 58 witnesses to bank robberies, some were directly involved (bank workers) and some were indirect,y involved (bystanders), recall was more than 75% accurate across all witnesses and the direct victims (with the most anxiety) were even more accurate, these findings confirm that anxiety doesn't reduce the accuracy of eyewitness recall and may even enhance it
• anxiety evaluation - limitations

  -unusualness not anxiety, Johnson and Scott's study may not have tested anxiety: ppts may have focused on the weapon because they were surprised rather than scared, Pickel (1998) did an experiment using scissors, a handgun, a wallet and a raw chicken as the handheld items in a hair salon video (where scissors were not unusual), eyewitness accuracy was poorer in the higher unusualness conditions (chicken and handgun), suggesting the weapon focus effect is caused by unusualness rather than anxiety and so Johnson and Scott's study tells us nothing specifically about the effects of anxiety on EWT
• the cognitive interview evaluation - limitations

  -some elements may be more useful than others: Milne and Bull (2002) found that each of the 4 techniques used alone work better than the standard police interview, but they also found that a combination of the 'report everything' and 'reinstate the context' produced better recall than any of the other elements alone or combined, this casts some doubt on the credibility of the overall CI

  -the CI is time consuming, police may be less likely to use the CI as it takes more time and training than the standard police interview: more time is needed to establish rapport with the witness so they can relax and the CI also needs special training which many forces don't have the resources to provide, suggesting the complete cognitive interview as it exists is not a realistic method for police to use and it may be better to focus on just a few key elements
• the cognitive interview evaluation - strengths

  -effectiveness of the CI, there is evidence the cognitive interview works: a meta-analysis by Kohnken et al. combined data from 55 studies comparing the CI and the standard police interview, the CI had an average 41% increase in accurate information compared to the standard interview, this shows that the CI is an effective technique in helping witnesses to recall information stored in the memory that is not immediately accessible
• who developed the cognitive interview into the enhanced cognitive interview?

  Fisher et al. (1987)