AQA A-LEVEL PSYCHOLOGY REVISION NOTES: MEMORY
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PSYCHOLOGY AQA A-LEVEL UNIT 1 (7182/1)
MODELS OF MEMORY; SHORT-TERM MEMORY AND LONG-TERM MEMORY
- The multi-store model of memory: sensory register, short-term memory and long-term memory. Features of each store: coding, capacity and duration
- Types of long-term memory: episodic, semantic, procedural
- The working memory model: central executive, phonological loop, visuo-spatial sketchpad and episodic buffer. Features of the model: coding and capacity
- Explanations for forgetting: proactive and retroactive interference and retrieval failure due to absence of cues
- Factors affecting the accuracy of eyewitness testimony: misleading information, including leading questions, post-event discussion, and anxiety
- Improving the accuracy of eyewitness testimony, including the use of the cognitive interview
Cognitive Psychology studies mental processes and abilities such as thought, language, perception, decision-making, etc. Memory is the cognitive ability which underlies much of what makes us human. It allows complex thought, language, learning, prediction and anticipation of the future, reflection on past events, etc.
As the neurophysiology (biological structure and function of the brain) of memory is extremely complex, cognitive psychologists generally use theoretical models to understand the processes underlying memory. There is a basic division between short-term memory (STM) and long-term memory (LTM) in terms of these different stores’ capacity, duration and encoding (in what format a memory trace is stored – visually, acoustically or semantically).
The Multi-Store Model examines how material is passed from short-term memory to long-term memory, and the Working Memory Model focuses on the different component parts of short-term memory.
The study of long-term memory reveals that memories relating to what we know about the world, ourselves and how to do things seem to be stored and accessed in different ways, and that forgetting in long-term memory may be the result of interference from competing memories or a failure to locate a particular memory due to a lack of cues (hints or reminders that aid recall).
An important practical application of memory research relates to the accuracy of people’s memories of crimes they may have witnessed (eye-witness testimony), and crime investigators use cognitive interview techniques derived from psychological findings to improve the accuracy and detail of witnesses’ memories.
DEFINITIONS & STUDIES – STM, LTM & DURATION, CAPACITY & ENCODING (Psychology A-level revision)
- Short-term memory (STM) refers to recall of information from the very recent past: e.g. remembering a telephone number or items on a shopping list.
- Long-term memory (LTM) refers to all memories which are more permanently stored: e.g. your own telephone number, names of old class mates, etc.
- Duration refers to the length for which memories can be stored.
- Capacity refers to the amount of information that can be stored.
- Encoding (or Coding) refers to how a memory is processed and This could be visually (as an image), acoustically (what the word sounds like) or semantically (to do with the meaning of the memory). For example, we may remember ‘dog’ by visualizing a dog we know, remembering the sound of the word ‘dog’, or recall a memory of being bitten by a dog when we were young.
- Retrieval refers to one’s ability to recall a memory.
In summary, basic findings regarding memory are
LONG TERM MEMORY
Approx. 18-30 seconds
7 (+/- 2) chunks of information
A STUDY INTO DURATION OF SHORT-TERM MEMORY
Peterson and Peterson (‘59)
- Conducted a study into the duration of STM using 24 students.
- Subjects were given a nonsense trigram (three random, non-meaningful letters: e.g. HXT rather than JAR, to prevent words being ‘meaningful and thus better remembered) and then given a number from which they had to count backwards from in 3s or 4s to stop them rehearsing the trigram.
- After either 3, 6, 9, 12, 15 or 18 seconds they were told to stop counting and remember the trigram. The researchers recorded the % of trigrams correctly recalled for each time interval.
- After 3 seconds, participants remembered about 90% of the time. After 18 seconds, this fell to only 2%.
- This suggests that the duration of STM is 18 seconds at most when rehearsal is prevented.
A STUDY INTO CAPACITY OF SHORT-TERM MEMORY
- Reviewed a number of studies where participants were asked to remember the number of dots flashed up onto a screen, musical notes, digits, letters or words.
- All studies found that STM’s capacity was 7 (+/-2) items.
- More can be remembered by chunking information together, e.g. remembering 5, 2, 7, 4, 6, 1 as 52, 74, 61. Equally, we can remember 5 words as well as we can 5 letters, although the larger the chunk, the less chunks can be remembered.
A STUDY INTO ENCODING IN MEMORY
- Gave participants lists of words that were either
- Acoustically similar – cat, cab, can
- Acoustically dissimilar – pit, few, cow
- Semantically similar – great, large, big
- Semantically dissimilar – good, wide, thin
They were then asked to recall these words immediately.
- Words that sounded similar were by far the hardest to remember suggesting that STM stores information acoustically: e. subjects confused the acoustically similar words with each other.
- He then presented lists of words in one of the 4 categories above and tested recall after 20 minutes. This time, words that were similar in meaning had the poorest recall. Thus, he concluded that LTM mainly codes memories
THE MULTI-STORE MODEL OF MEMORY (MSM) (A-level Psychology revision)
Atkinson & Shiffrin (‘68)
- Environmental stimuli from the senses is received by the sensory memory (SM), where it remains for split seconds (Duration: approx. 250 milliseconds, Capacity: unlimited).
- If attention is paid to any of this information data is transferred to short-term memory (STM) otherwise it immediately decays and is forgotten.
- (The sensory memory does not have a particular form of encoding – rather encoding depends on which mode (sight, sound, touch, etc.) that it arrived in – therefore, its encoding is referred to as modality specific.
- Information will decay from the STM very quickly (within 18-30 seconds) if it is not subject to maintenance rehearsal: i.e. repeated over and over again.
- As STM has a limited capacity, it might become displaced by other competing information.
- Rehearsal of information will allow it to be transferred to LTM – the more it is rehearsed the better it will be remembered.
- Once in the LTM memories can be retrieved.
EVALUATION - strengths
Research evidence supporting the MSM
- HM (the participant in a case study) had his hippocampus removed in an operation to reduce his epilepsy.
- After the operation he could remember things he had just been told suggesting that his STM was intact, but he could not transfer this information to the LTM: for example, he would read the same magazine repeatedly and was unable to recognise the psychologists who treated him.
- He had LTMs from 10 years before his surgery but had lost LTMs for the 10 years up until his surgery.
- This provides evidence for the MSMs claim that STM and LTM are 2 separate and distinct stores.
Glanzer (’66) – The Primacy-Recency Effect
- Found that when subjects were presented with a list of words and then asked to recall these words they tended to remember ones from the beginning (primacy) and from the end (recency). The primacy effect occurs as words have been transferred to LTM through rehearsal; the recency effect occurs as the last words on the list are recalled from STM before they decay.
- By adding a 30m second delay before participants recalled words memory of later words on the list fell dramatically as they decayed from STM.
- This provides evidence for the MSMs claim that STM and LTM are 2 separate and distinct stores.
Research evidence contradicting the MSM
- The MSM is now considered a rather basic analysis which oversimplifies memory structures and processes: in particular that the structures of STM and LTM each operate in a single, uniform fashion. The Working Memory Model provides evidence that STM is composed of several different stores which handle visual and acoustic information differently and separately. Research into LTM also indicates we have separate memory stores for memories about our knowledge (semantic), our personal history (episodic) and our ability to do things (procedural).
Shallice and Warrington (‘70)
- KF suffered brain damage which resulted in difficulty dealing with verbal information in STM, but a normal ability to process visual information in STM.
- This suggests that STM is not a single store as the model proposes and implies (as the Working Memory Model does) that STM is composed of a number of separate stores.
Craik and Tulving’s Levels of Processing Model argues that the strength of long term memories is not simply determined by the amount of rehearsal that takes place but rather the type of rehearsal that takes place. They conducted a study where participants were given a list of nouns and then asked a question about each word.
- Is the word printed in capital letters? – shallow processing (what the word looks like).
- Does the word rhyme with ‘train’? – phonemic processing (what the word sounds like).
- Is the word a type of fruit? – deep semantic processing (the meaning of the word).
Words from the 3rd condition were recalled most easily suggesting that elaborative rehearsal (which involves deeper analysis/processing) results in a stronger memory trace: i.e. we will remember material that we find more interesting, relevant and meaningful for us.
TYPES OF LONG-TERM MEMORY (AQA A-level Psychology revision)
LT memories of your personal experiences and the time, place, context and emotions surrounding events which happened in the past: e.g. your 1st day at school. Episodic memories are explicit: i.e. require conscious effort.
LT memory of knowledge of factual information which is not personal to you but is shared by a number of people: e.g. the capital of Britain is London. Semantic memories include factual knowledge but also knowledge relating to the properties of objects (e.g. chilli is hot), rules of social behaviour, and abstract concepts such as maths and physics. Semantic memories are explicit: i.e. require conscious effort.
Memories of how to do things: e.g. ride a bicycle. These are acquired through learning, repetition and practice and are often implicit - unconscious and automatic (i.e. we don’t need to consciously think about how to swim).
EVIDENCE FROM BRAIN SCANS
- Research with brain scans has found that different brain areas are associated with the 3 types of LT memory.
- Episodic memories occur in the hippocampus and other portions of the temporal lobe and the frontal lobe.
- Semantic memory is associated with the temporal lobe.
- Procedural memories occur in the cerebellum, basal ganglia and limbic system. The cerebellum is also associated with motor skills: i.e. skills to do with movement.
DIFFERENCE BETWEEN PROCEDURAL AND DECLARATIVE MEMORIES
With the case study of HM we had previously learnt that after surgery his ability to form new LT memories was interfered with. This is a simplification: in fact, he could form new procedural memories in his LTM but could not form new episodic or semantic ones. This provides evidence for the claim that LTM is not a single store but composed of different stores handling different types of information.
DIFFERENCE BETWEEN EPISODIC AND SEMANTIC MEMORIES
It can be argued that the ability to form new episodic memories is the key to allowing us to form new semantic memories; i.e. our memory of events allows us to form memories of new facts. For example, I went to the art gallery (episodic) and learned about Picasso (semantic).
Researchers studying Alzheimer’s patients have found that some patients keep the ability to form new episodic memories but not new semantic ones which provides evidence for this argument. This is an example of dissociation – a separation between 2 abilities.
However, this doesn’t prove that episodic and semantic memories are entirely separate. Also, there are cases where the reverse is true – Alzheimer’s patients who can form new semantic memories but not new episodic ones.
PRIMING – A 4TH KIND OF LTM
Priming is concerned with how implicit memories affect the responses a person makes: for example, if someone is told the word yellow then asked to name a fruit they are likely to answer ‘banana’ (yellow + fruit). This association is automatic and unconscious. Research has shown that priming is controlled by a different area of the brain from the temporal brain area which controls explicit memories. Some researchers have, therefore, suggested the existence of a 4th type of LTM – the ‘perceptual-representation system’ (PRS) which is concerned with recognising and forming associations between particular stimuli.
THE WORKING MEMORY MODEL (WMM) (AQA A-level Psychology revision guide)
Baddeley & Hitch (’74)
The WMM takes a more sophisticated view of STM as being composed of various separate but inter-related stores where different types of operations are performed on incoming information by different parts of the STM before being passed onto the LTM or forgotten.
B&H proposed that the STM is composed of
The Central Executive
- Information arrives from the senses or from the long-term memory and the Central Executive decides which of the ‘slave systems’ (below) are needed to deal with it.
- It deals with a number of tasks, e.g. attention, switching attention between tasks and other higher mental processes such as decision-making and problem-solving.
The Phonological Loop
- Deals with auditory/acoustic information and has a limited capacity.
- Is subdivided into:
- The Phonological Store (inner ear) – retains words we hear for 1–2 seconds.
- The Articulatory Process (inner voice) – retains information we hear or see by silently repeating it (looped) like an inner voice.
- The inner eye - holds visual (how things look) and spatial (the relationship between things) information.
- Manipulates mental imagery, perceives movement and recognises patterns.
- A temporary storage area which combines and brings together information received from the phonological loop, the visuo-spatial sketchpad and the central executive.
EVALUATION - strengths
The WMM is well supported by research evidence.
Baddeley and Hitch (‘74)
- Participants were given digits to rehearse while carrying out a verbal reasoning task. They performed well on both tasks.
- This suggests that working memory consists of several different components that can work independently of one another and so handle more than one task at a time.
- Participants followed a spot of light moving round a circular path whilst either performing a visual task or a verbal
- Participants performed poorly at the visual task but not at the verbal task. This is because the visuo-spatial sketchpad became overloaded by having to deal with 2 visual tasks at once whereas performing a visual and a verbal task used 2 separate stores. This suggests that STM has a different visual and auditory store.
The model is also supported by research with brain damaged patients.
- KF - Had difficulty dealing with verbal information in STM, but a normal ability to process visual information in STM.
- SC – Had generally good learning abilities with the exception of being unable to learn word pairs that were presented out loud: i.e. had a problem with the phonological store only whilst other parts of his STM worked normally.
EVALUATION - weaknesses
We know little about the role of the Central Executive and what has been written about it is vague and difficult to test. Critics argue that the notion of a single Central Executive is wrong and there are probably several components. For example, Eslinger studied EVR who, after an operation on a cerebral tumour, performed well on reasoning tasks but had poor decision-making skills. The Central Executive is supposed to manage both of these areas. This case study indicates otherwise.
The above studies suggest separate stores for verbal and visual information as proposed by the WMM. However, as they are case studies based on single participants there is low population validity and findings should be generalised with caution.
The model also tends to ignore how STMs are passed on to LTM.
FORGETTING (A-level Psychology resources)
EXPLANATIONS FOR FORGETTING: PROACTIVE AND RETROACTIVE INTERFERENCE AND RETRIEVAL FAILURE DUE TO ABSENCE OF CUES
PROACTIVE AND RETROACTIVE INTERFERENCE
Interference refers to information heard either before or after another piece of information causing poorer recall of this information.
TYPE OF INTERFERENCE
Learn list of words in French
Learn list of words in German
Recall list of words in French
Retroactive Interference (RI): learning of B interferes with recall of A
Learn list of words in French
Learn list of words in German
Recall list of words in German
Proactive Interference (PI): learning of A interferes with recall of B
RETROACTIVE INTERFERENCE (RI)
Muller gave participants a list of nonsense syllables (e.g. HDX) to learn for 6 minutes then after an interval asked them to recall these syllables. 1 group of subjects were given nothing to do in the interval, the other group were asked to study and describe 3 paintings. Those in the 2nd condition showed far poorer recall – thus providing evidence for RI.
PROACTIVE INTERFERENCE (PI)
Underwood found that when presented with a list of words, subjects had better memory of words at the beginning of the list compared to words towards the end of the list. This implies that earlier information is interfering with later information – thus providing evidence for PI.
SIMILARITY OF INFORMATION
Interference effects are most clear when the 2 lists of information to be learnt are very similar to each other.
McGeogh ran the following study:
- Condition 1: subjects learn 10 adjectives (e.g. big, wet) – rest 10 minutes – learn 10 adjectives which are synonyms of 1st list (e.g. large, damp). Then recall original 10 adjectives.
- Condition 2: learn 10 adjectives (e.g. big, wet) – rest 10 minutes – learn 10 nonsense syllables (e.g. HVP). Then recall original 10 adjectives.
Subjects in Condition 2 performed far better than condition 1 indicating that similarity of information causes increased interference and forgetting.
DECAY VS. INTERFERENCE
A real world study was carried out by Baddeley who asked rugby players to recall the names of the teams they had played against over the previous season. Some of the players had played in all of the games, others had missed games due to injury. The decay theory of forgetting simply states that memories get worse (decay) over time. However, Baddeley found that the more games a player had played, the worse their memory of other teams was. This provides evidence for proactive interference rather than decay theory as competing information from earlier on in the season caused poorer recall of all games played.
- As with much research into memory, many studies suffer from a lack of ecological validity in that they ask subjects to recall words in artificial conditions where information given is fairly meaningless and subjects may not be motivated to recall memories as they are in the real world. This may make interference effects appear worse than they are in real life situations.
- Research shows that interference plays a major role in the public’s memory for adverts. Danaher found that the public’s memory for advertisements was worse when people were exposed to 2 or more adverts for competing brands within a week. This has important implications for the money spent on and timing of adverts: for example, it may be better to expose people to 1 advert many times over a short period of time (so it won’t be subject to interference) rather than just showing the advert periodically (where it will be subject to interference).
Retrieval failure theory argues that rather than forgetting information we sometimes simply have a problem locating and retrieving it from our LTM. ‘Cues’ are some sort of reminder or prompt which allows us to locate and recall this information from LTM. For example, we cannot remember someone’s name but if we are told their initials it may serve as a retrieval cue.
The encoding specificity principal argues that we will have superior memory recall if asked to recall something in the same situation in which we learnt it: i.e. you will perform best in an exam if it’s held in the same room you studied in.
Numerous studies show that retrieval cues improve recall. For example, Tulving gave participants 48 words belonging to 12 categories. Each word was presented as a category + word: e.g. animal + lion. When asked to recall words, participants given the category retrieval cue recalled about +20% more words than those not given retrieval cues.
This relates to improved memory recall if one is asked recall something in the place/situation in which it was originally learnt.
Abernethy conducted a study where students were taught a piece of material and were then tested in (i) the same room with the same teacher, (ii) the same room with a different teacher, (iii) the same teacher in a different room, (iv) a different teacher in a different room. Those in condition (i) performed best – presumably because the room and the teacher acted as cues. Additionally, it was found that weakest students benefitted most from context cues.
Similarly, a group of scuba divers who learnt words underwater had better memory recall later on when asked to recall these words underwater than they did on land.
A similar effect seems to occur with individual’s emotional/psychological state.
Godwin asked volunteers to learn a list of words when either drunk or sober. Each group later showed better memory recall when they were in the same state they originally learnt the words in.
There is a great deal of research evidence to support the effectiveness of retrieval cues and this research has potentially important applications in, for example, exams. Although it’s unrealistic to expect that you could be taught and examined in the same room, it has been shown that using imagination to visualise the room you were taught in can improve memory recall.
However, although retrieval cues can help recall fairly simple pieces of information such as names and dates, memory of complex information is less likely to be aided by simple cues and is more dependent on more complex memory processes to do with the meaningfulness of material we have learnt: see, for example, the Levels of Processing model of memory which states that the depth of a memory trace will be determined by how semantically meaningful material is to us.
EYEWITNESS TESTIMONY (AQA A-level Psychology resources)
FACTORS AFFECTING THE ACCURACY OF EYEWITNESS TESTIMONY: MISLEADING INFORMATION, INCLUDING LEADING QUESTIONS, POST-EVENT DISCUSSION; EWT & ANXIETY
The term eyewitness testimony refers to the account given by those who have witnessed crime scene events and the identities of perpetrators.
Accuracy of EWT is hugely importance in relation to the correct identification and appropriate sentencing of perpetrators and avoiding the incorrect identification and false imprisonment of the innocent.
Much research indicates that eye–witnesses’ memories may be subject to warping, distortion and even the implanting of false memories.
MISLEADING INFORMATION/LEADING QUESTIONS
A leading question is one which suggests to the witness what answer is desired or leads them to the desired answer: e.g. ‘you shot X on the night of the 15th, didn’t you?’ A non-leading form of this question would be ‘where were you on the night of the 15th?’
Loftus and Palmer (‘74) – Experiment 1
- 45 student participants watched 7 videos of car crashes and were then asked to fill in a questionnaire which asked questions about what they had seen.
- Different groups of participants were given 5 different variations of 1 critical question regarded what speed the cars were travelling at:
- ‘How fast were the cars going when they smashed/collided/bumped/ hit/contacted each other?’
- The mean speed given by the participants who had seen the word ‘smashed’ was 8 mph, but for those who had seen the word ‘contacted’ it was only 31.8 mph
- They concluded that post-event information in the form of a misleading/leading question can distort memory of events.
Loftus and Palmer (‘74) – Experiment 2
- 3 groups of participants were shown a film of a car accident.
- Group 1 heard the word ‘smashed’, Group 2 heard the word ‘hit’, and Group 3 (the control condition) heard no adjective. A week later participants were asked 10 questions about the accident including: ‘did you see any broken glass?’ There was no broken glass in the film.
- 47% of those who heard the word ‘smashed’ said ‘yes’, as opposed to only 16% of Group 2 and 14% of Group 3.
- Thus, misleading information can change the way in which information is stored in memory.
The memory of an event may also be altered by discussing memories of that event with others.
A study by Gabbert (’03) put participants in pairs to watch two separate videos. In one condition, participants were encouraged to discuss what had seen with each other. In the second condition they did not discuss what they had seen. When later questioned individually about the video they had seen, 71% of participants in condition 1 incorporated material that they had heard from their partner into their own memory of what they had seen. Thus, EWT can be distorted through discussion with others.
EVALUATION - strengths
- Loftus’ research seems reliable – findings have been reproduced time after time and received support from subsequent experimentation. For example:
- Loftus & Zanni (‘75) showed 2 groups of participants a film of a car accident, and asked one group:
- ‘Did you see the broken headlight?’
And the other group:
- ‘Did you see a broken headlight?’
- They were more likely to report seeing a broken headlight in the first condition. Using the word ‘the’ suggests that a broken headlight did exist, rather than the word ‘a’, so altering even a word seems able to influence memory.
EVALUATION - weaknesses
- Given that Loftus’ studies were laboratory experiments they suffer a lack of ecological validity and subjects may have shown demand characteristics – because they were only watching a film of an accident they would not have been as emotionally aroused as if they had watched a real accident and they may not have taken the experiment seriously. Foster (’94) found that if participants were watching a real life robbery and thought their responses would influence a trial their responses were much more accurate.
- Research in the real world has not always supported lab work: for example, Christensen (‘93) interviewed 14 witnesses to a real armed robbery 3 months after the incident. Despite having seen an inaccurate reconstruction of the crime on television they were 84% accurate in their recall of events indicating that misleading information might not have such a strong influence in real life events.
EYE-WITNESS TESTIMONY & ANXIETY
Anxiety is a negative emotional state of anticipation associated with high levels of physiological and psychological arousal (such as might be experienced whilst witnessing a crime).
- Deffenbacher (’04) carried out a meta-analysis of 18 studies which looked at the effect of heightened anxiety on accuracy of eye-witness recall and found strong support for the hypothesis that high levels of stress negatively impact on eye-witness memory.
- The weapon-focus effect refers to the phenomenon whereby witnesses to violent crimes often focus on the central details of the attack (e.g. the weapon) as opposed to peripheral details (e.g. the attacker’s facial features, etc.). In a study by Loftus, in condition 1 participants heard a discussion in an adjoining room and a man then emerge holding a pen, and in condition 2 a man emerge holding a blood covered knife. When asked to identify the man from 50 photos, participants in condition 1 were 49% accurate as opposed to 33% accurate for condition 2.
- However, some studies conducted in the real world have found that emotional arousal may enhance recall: for example, Christensen (‘93) interviewed 58 witnesses of real armed bank robberies 4-15 months after the incident. Those witnesses who had been threatened in some way (bank clerks), and thus experienced heightened anxiety, were often more accurate and detailed in their recall than bystanders of other employees who had not been threatened. This also lends support to the concept of ‘flashbulb memories’ – where intense emotional experiences create a stronger, highly detailed memory trace.
- A major problem with drawing firm conclusions in this field is the contradictory findings. Deffenbacher suggests this contradiction could be explained by the Yerkes-Dodson Law whereby a medium level of arousal leads to optimum performance (in this case, recall) and low and excessively high arousal is associated with inhibited performance (recall).
- However, in the Christensen study, those who experienced very high arousal as a result of being threatened had superior recall. However, this may have been due to the fact that they were closer to the perpetrator and thus had a better opportunity to observe and recall events accurately.
- Loftus’ research into the weapons effect does not tell us whether memory was poorer as a result of anxiety or simply because participants were looking at the knife rather than the man’s features: i.e. they were distracted or surprised.
To test this, a study by Pickel (98) had a confederate walking into a hairdresser with (i) scissors (high threat, low surprise), (ii) a handgun (high threat, high surprise), (iii) a wallet (low threat, low surprise) or a raw chicken (low threat, high surprise). Identification was poorest in the high surprise conditions suggesting that surprise rather than anxiety lies behind poor memory recall among eye-witnesses.
- Many studies into the effects of anxiety on recall are laboratory based experiments, and although this increases the chance of researchers being able to isolate the effect of high or low levels of anxiety on recall, lab studies lack ecological validity meaning they are not representative of, and therefore cannot be generalised to real life.
IMPROVING THE ACCURACY OF EYEWITNESS TESTIMONY, INCLUDING THE USE OF THE COGNITIVE INTERVIEW (A-level Psychology notes)
THE COGNITIVE INTERVIEW
Research into EWT has also focused on how best to improve the accuracy, detail and quality of witness recall.
The Cognitive Interview (CI) is a recent and highly effective tool police employ when questioning witnesses.
Fisher and Geiselman (’92) reviewed relevant literature on memory and proposed that people remember events better when they are provided with retrieval cues – by re-stating the context and re-experiencing the event witness recall might improve.
The Cognitive Interview is composed of 4 elements.
- Report Everything
The witness is told to mentally recall everything surrounding the event even if it seems trivial – the weather, what they were thinking and feeling, what had just happened beforehand, etc. As memories are interconnected with one another, one memory may act as a retrieval cue for another more important memory.
- Mental Reinstatement of Original Context
The witness is told to mentally recreate every physical and psychological detail of what they witnessed. The aim is to draw out retrieval cues which may prompt recall of previously forgotten information.
- Change the Order
The witness is told to report the episode in different time orders, moving backwards and forwards in time. Our memories may be influenced by our general expectations of how things usually happen. Changing time order disrupts these general expectations and may reveal previously forgotten information.
- Recall from Changed Perspective
The witness is told to report the episode from other perspectives: for example, how it would have looked to other witnesses.
1 and 2 are based on the principle that if there is consistency between the actual incident and the recreated situation it is likely the quality and quantity of recall will improve.
3 and 4 are based on the assumption that information which has been observed can be retrieved through a number of different ‘routes’ into memory so varying these ‘routes’ might increase recall.
EVALUATION - strengths
Research into the CI indicates good support for its ability to improve recall detail and accuracy.
Geiselman et al. (‘85)
- Participants were shown a video of a simulated crime and then tested with a cognitive interview, a standard police interview, or an interview under the influence of hypnosis.
- The cognitive interview was the most successful of the three.
- As this study was conducted in a laboratory using a non-realistic event levels of ecological validity are low; however, research using the enhanced cognitive interview (see below) in the real world has been encouraging.
Kohnken (’99) conducted a meta-analysis of 53 studies and found an average increase of 34% in the amount of correct information recalled when using CI as opposed to traditional interviewing techniques.
EVALUATION - weaknesses
There have been some criticisms of the cognitive interview.
- The CI is not suitable for children under the age of 6 who, research has suggested, are slightly less accurate when using the cognitive interview, find instructions difficult to understand and may generate more inaccurate material in response to CI techniques. The CI begins to be a suitable technique for children aged around 8+.
- It is unpopular with some police as it takes a long time to complete and it is time consuming and expensive to train staff in techniques. For this reason many police forces have not been able to devote more than a few hours training to the CI and many officers prefer to devote time available to techniques they believe will lead them to the information they require. For this reason, in the UK, the CI is not widely used.
- Although it generates more information, some research has suggested that it also generates more incorrect information.
More recently, the ‘enhanced cognitive interview’ has been developed which adds to the above by minimising distractions, asking open-ended questions, pausing after each response, avoiding interruption and avoiding any judgemental comments.