Memory Flashcards
1
Q
Short term memory definition
A
(STM) The limited-capacity memory store. In STM, coding is mainly acoustic (sounds), capacity is between 5 and 9 items on average, duration is about 18 seconds.
2
Q
Long term memory definition
A
(LTM) The permanent memory store. In LTM, coding is mainly semantic (meaning), it has unlimited capacity and can store memories for up to a lifetime.
3
Q
Coding definition:
A
The format in which information is stored in the various memory stores.
4
Q
Capacity definition:
A
The amount of information that can be held in a memory store.
5
Q
Duration definition:
A
The length of time information can be held in memory.
6
Q
Research on coding (AO1)
A
Information is stored in memory in different forms, depending on the memory store.
coding- The process of converting information between different forms
Alan Baddeley (1966a, 1966b) gave different lists of words to four groups of participants to remember:
• Group 1 (acoustically similar)(e.g. cat, cab, can).
• Group 2 (acoustically dissimilar): (e.g. pit, few, cow).
• Group 3 (semantically similar): (e.g. great, large, big).
• Group 4 (semantically dissimilar): (e.g. good, huge, hot).
Participants were asked to recall them in the correct order. When they did this task immediately, recalling from short-term memory (STM), did worse with acoustically similar words. When recalling words after a time interval of 20 minutes, recalling from long-term memory (LTM), did worse with the semantically similar words.
- so information is coded acoustically in STM and semantically in LTM.
7
Q
Research on capacity Digit span (AO1)
A
How much information can STM hold at one time (capacity)?
Joseph Jacobs (1887)- measured digit span. e.g, the researcher reads out four digits and the participant recalls these out loud in the correct order. If this is correct the researcher reads out five digits and so on until the participant cannot recall the order correctly. This indicates the individuals digit span.
- found that the mean span for digits across all participants was 9.3 items.
- mean span for letters was 7.3.
8
Q
Research on capacity Span of memory and chunking (AO1)
A
George Miller (1956) made observations of everyday practice. e.g, noted that things come in sevens: notes on the musical scale, days of the week, seven deadly sins, etc.
- thought that the span (i.e. capacity) of STM is about 7 items, plus or minus 2.
- also noted that people can recall five words as easily as they can recall five letters. We do this by chunking - grouping sets of digits or letters into units or chunks.
9
Q
Research on duration Duration of STM (AO1)
A
Margaret and Lloyd Peterson (1959) tested 24 students in eight trials each (a ‘trial’ is one test). On each trial the student was given a consonant syllable (such as YCG) to remember + given a 3-digit number.
- student counted backwards from this number until told to stop. was to prevent any mental rehearsal of the consonant syllable (which would increase the duration of STM memory for the syllable).
On each trial they were told to stop after varying periods of time: 3, 6, 9, 12, 15 or 18 seconds (the retention interval). After 3 seconds, average recall was about 80%, after 18 seconds it was about 3%.
- their findings suggested that STM duration approx 18 seconds, unless we repeat information (i.e. verbal rehearsal).
10
Q
Research on duration LTM
A
Harry Bahrick et al. (1975) studied 392 American participants aged between 17 and 74. High school yearbooks were obtained from the participants or directly from some schools. Recall was tested in various ways, : (1) photo-recognition test consisting of 50 photos, some from the participants’ high school yearbooks, (2) free recall test where participants recalled all the names of their graduating class.
Participants tested within 15 years of graduation were about 90% accurate in photo recognition. After 48 years, recall declined to about 70% for photo recognition. Free recall was less accurate than recognition - about 60% after 15 years, dropping to 30% after 48 years.
- so LTM may last up to a lifetime for some material.
11
Q
Separate memory stores (AO3)
A
strength: Baddeley’s study identified a clear difference between two memory stores.
Later research shows there are some exceptions to Baddeley’s findings. But the idea that STM uses mostly acoustic coding and LTM mostly semantic.
This was an important step in our understanding of the memory system, which led to the multi-store model
12
Q
Baddley Artificial stimuli (AO3)
A
limitation: study was that it used quite artificial stimuli rather than meaningful material.
- e.g, the word lists had no personal meaning to participants.
So Baddeley’s findings may not tell us much about coding in different kinds of memory tasks, especially in everyday life. When processing more meaningful information, people may use semantic coding even for STM tasks.
- so findings from this study have limited application.
13
Q
digit span valid study (AO3)
A
strength- study has been replicated.
- study is a very old one and early research in psychology often lacked adequate controls. e.g, some participants’ digit spans might have been underestimated as they were distracted during testing (confounding variable). Despite this, Jacobs’ findings have been confirmed by other, better controlled studies since (e.g. Bopp and Verhaeghen 2005).
- so Jacobs’ study is a valid test of digit span in STM.
14
Q
Not so many chunks (AO3)
A
limitation: he may have overestimated
STM capacity.
Nelson Cowan (2001) reviewed other research and concluded that the capacity of STM is only about 4 (plus or minus 1) chunks.
This suggests that the lower end of Miller’s estimate (five items) is more appropriate than seven items.
15
Q
Meaningless stimuli in STM study (AO3)
A
limitation: the stimulus material was artificial.
The study is not completely irrelevant as we do sometimes try to remember fairly meaningless material (e.g. phone numbers). Even so, recalling consonant syllables does not reflect most everyday memory activities where what we are trying to remember is meaningful.
- so study lacked external validity.
16
Q
LTM research high external validity (AO3)
A
strength- high external validity as researchers investigated meaningful memories (i.e. of people’s names and faces). When studies on LTM were conducted with meaningless pictures to be remembered, recall rates were lower (e.g. Shepard 1967).
- so Bahrick et al’s findings reflect a more real’ estimate of the duration of LTM.
17
Q
Multi-store model definition:
A
(MSM) A representation of how memory works in terms of three stores called the sensory register, short-term memory (STM) and long-term memory (LTM). It also describes how information is transferred from one store to another, what makes some memories last and what makes some memories disappear.
18
Q
Sensory register definition:
A
The memory stores for each of our five senses, such as vision (iconic store) and hearing (echoic store). Coding in the iconic sensory register is visual and in the echoic sensory register it is acoustic (sounds). The capacity of sensory registers is huge (millions of receptors) and information lasts for a very short time (less than half a second).
19
Q
The multi-store model (AO1)
A
Richard Atkinson and Richard Shiffrin’s (1968, 1971) multi-store model (MSM) describes how information flows through the memory system
- Model suggests that memory is made up of three stores linked by processing.
20
Q
Sensory register (AO1)
A
stimuli from the environment (eg. the sound of someone talking) pass into the sensory register
(SR). This part of memory comprises memory stores for each of our five senses. Coding in each store is modality-specific (i.e. it depends on the sense). e.g , the store coding for visual information is iconic memory and the store coding acoustically (i.e. for sound) is echoic memory. There are other sensory stores for touch, taste and smell information.
Duration of material in the SRs is less than half a second. have a very high capacity, for example over one hundred million cells in one eye, each storing data.
Information passes further into the memory system only if you pay attention to it (so attention is the key process).
21
Q
Short-term memory (AO1)
A
coded mainly acoustically lasts approx 18 seconds unless rehearsed, so STM is more of a temporary store. STM is a limited-capacity store as it can only contain a certain number of ‘things’ before forgetting occurs.
- Cowan’s research suggests it might be more like five rather than nine.
Maintenance rehearsal occurs when we repeat (rehearse) material to ourselves over and over again. We can keep the information in our STMs as long as we rehearse it. If we rehearse it long enough, it passes into long-term memory (LTM).
22
Q
Long term memory (AO1)
A
potentially permanent memory store for information that has been rehearsed for a prolonged time. We have already seen that LMs are coded mostly semantically (i.e. in terms of meaning).
- duration may be up to a lifetime. e.g, Bahrick et al. (1975) found many of their participants were able to recognise the names and faces of their school classmates almost 50 years after graduating. The capacity of LTM is thought to be practically unlimited.
According to the MSM, when we want to recall information from LTM, it has to be transferred back into STM by retrieval.
23
Q
Memory Research support (AO3)
A
strength: from studies showing that STM and LTM are different.
Alan Baddeley (1966,) found that we tend to mix up words that sound similar when we are using our
STMs. But we mix up words that have similar meanings when we use our LTMs. Further support comes from the studies of capacity and duration we encountered in the previous spread.
These studies clearly show that STM and LTM are separate and independent memory stores, as claimed by the MSM.
24
Q
Memory Research support counterpoint (AO3)
A
in everyday life we form memories related to all sorts of useful things - people’s faces, their names, facts, places, etc. But many of the studies that support the MSM used none of these materials. Instead, they used digits, letters (Jacobs), and sometimes words (Baddeley). They even used what are known as consonant syllables that have no meaning (Peterson and Peterson).
This means that the MSM may not be a valid model of how memory works in our everyday lives where we have to remember much more meaningful information.
25
More than one STM store (AO3)
limitation: evidence of more than one STM store.
- Tim Shallice and Elizabeth Warrington (1970) studied a client they referred to as KF who had a clinical memory disorder called amnesia.
KF's STM for digits was very poor when they were read out loud to him. But his recall was much better when he read the digits to himself.
- KF (and others) showed that there could even be another short-term store for non-verbal sounds (e.g. noises).
- so the MSM is wrong in claiming that there is just one STM store processing different types of information (e.g. visual, auditory, etc.).
26
Elaborative rehearsal (AO3)
limitation: prolonged rehearsal is not needed for transfer to LTM.
According to the MSM, what matters about rehearsal is the amount of it - the more you rehearse something, the more likely it is to transfer to LTM. This is prolonged rehearsal. But Fergus Craik and Michael Watkins (1973) found that the type of rehearsal is more important than the amount. Elaborative rehearsal is needed for long-term storage.
This occurs when you link the information to your existing knowledge, or you think about what it means. This means that information can be transferred to LTM without prolonged rehearsal.
This suggests that the MSM does not fully explain how long-term storage is achieved.
27
Bygone model (AO3)
Atkinson and Shiffrin based the MSM on the research evidence available at the time that showed STM and LTM to be single memory stores, separate and independent from each other.
- but there is a lot of research evidence that LTM, like STM, is not a single memory store. e.g, we have one long-term store for our memories of facts about the world, and we have a different one for our memories of how to ride a bicycle. Combined with research showing there is more than one type of STM and more than one type of rehearsal, the MSM is an oversimplified model of memory.
28
Episodic memory definition:
A long-term memory store for personal events. It includes memories of when the events occurred and of the people, objects, places and behaviours involved. Memories from this store have to be retrieved consciously and with effort.
29
Semantic memory definition:
Along-term memory store for our knowledge of the world. This includes facts and our knowledge of what words and concepts mean. These memories usually also need to be recalled deliberately.
30
Procedural memory definition:
Along-term memory store for our knowledge of how to do things. This includes our memories of learned skills. We usually recall these memories without making a conscious or deliberate effort.
31
Types of long-term memory (AO1):
Endel Tulving 1985) was one of the first cognitive psychologists to realise that the multi-store mode's view of long-term memory (LTM) was too simplistic and inflexible. Tulving proposed that there are in fact three LTM stores, containing quite different types of information. He called them episodic memory, semantic memory and procedural memory.
32
Episodic memory (AO1):
- it is our ability to recall events (episodes) from our lives. This has been likened to a diary, a record of daily personal experiences. Some examples are: your most recent visit to the dentist, a gig you went to last week, the psychology class you had yesterday, the breakfast you ate this morning, and so on. These memories are complex.
First of all, they are 'time-stamped' - in other words you remember when they happened as well as what happened. Episodic memories also store information about how events relate to each other in time.
Second, your memory of a single episode will include several elements, such as people and places, objects and behaviours. All of these memories are interwoven to produce a single memory.
Third, you have to make a conscious effort to recall episodic memories. You do this quickly, but you are still aware that you are searching for your memory of what happened when you went to the dentist.
33
Semantic memory (AO1):
- contains our shared knowledge of the world. It has been likened to a combination of an encyclopaedia and a dictionary. So it includes knowledge of such things as: how to apply to university, what an orange tastes like, what zombies like for dinner and the meaning of words.
This last one is important. Your semantic memory contains your knowledge of an impressive number of concepts such as 'animals, love and 'Frozen.
These memories are not time-stamped. We don't usually remember when we first heard about the new Frozen film, for example. Semantic knowledge is less personal and more about facts we all share. It contains an immense collection of material which, given its nature, Is constantly being added to. According to Tulving, it is less vulnerable to distortion and forgetting than episodic memory.
34
Procedural memory (AO1):
This is our memory for actions or skills, or basically how we do things. We can recall these memories without conscious awareness or much effort (eventually). A good example is driving a car. Our ability to do this becomes automatic through practice. We change gear without having to recall how. We indicate left or right without even realising we've done so.
These are the sorts of skills we might even find quite hard to explain to someone else. If you try to describe what you are doing as you drive the car, the task may well become more difficult.
35
types of LTM Clinical evidence (AO3):
strength: evidence from the famous case studies of HM (Henry Molaison) and Clive Wearing.
Episodic memory in both men was severely impaired due to brain damage (caused by an operation and infection respectively). But their semantic memories were relatively unaffected. They still understood the meaning of words. For example, HM could not recall stroking a dog half an hour earlier but he did not need to have the concept of 'dog' explained to him. Their procedural memories were also intact.
They both still knew how to walk and speak, and Clive Wearing (a professional musician) knew how to read music, sing and play the piano.
This evidence supports Tulving's view that there are different memory stores in
LTM - one store can be damaged but other stores are unaffected
36
clinical evidence Counterpoint LTM (AO3):
Studying people with brain injuries can help researchers to understand how memory is supposed to work normally. But clinical studies are not perfect. A major limitation is that they lack control of variables. The brain injuries experienced by participants were usually unexpected. The researcher had no way of controlling what happened to the participant before or during the injury.
The researcher has no knowledge of the individual's memory before the damage.
Without this, it is difficult to judge exactly how much worse it is afterwards.
This lack of control limits what clinical studies can tell us about different
types of LTM.
37
Conflicting neuroimaging evidence LTM (AO3):
limitation: conflicting research findings linking types of LTM to areas of the brain.
Randy Buckner and Steven Petersen (1996) reviewed evidence regarding the location of semantic and episodic memory. They concluded that semantic memory is located in the left side of the prefrontal cortex and episodic memory on the right. However, other research links the left prefrontal cortex with episodic memories and the right prefrontal cortex with semantic memories (Tulving et al. 1994).
This challenges any neurophysiological evidence to support types of memory as there is poor agreement on where each type might be located.
38
Real-world application LTM (AO3)
strength: understanding types of LTM allows psychologists to help people with memory problems.
e.g as people age, they experience memory loss. But research has shown this seems to be specific to episodic memory - it becomes harder to recall memories of personal events/experiences that occurred relatively recently though past episodic memories remain intact. Sylvie Belleville et al. 2006) devised an intervention to improve episodic memories in older people. The trained participants performed better on a test of episodic memory after training than a control group.
This shows that distinguishing between types of LTM enables specific treatments to be developed.
39
LTM Same or different? (AO3):
Tulving (2002) has taken the view that episodic memory is a
'specialised subcategory' of semantic memory (so essentially the same store). His research showed that some people with amnesia have a functioning semantic memory alongside a damaged episodic memory. But he also concluded it is not possible to have a functioning episodic memory with a damaged semantic memory.
However, John Hodges and Karalyn Patterson (2007) found that some people with Alzheimer's disease (a type of dementia) could form new episodic memories but not semantic memories.
40
Working memory model (WMM) definition:
A representation of short-term memory (STM). It suggests that STM is a dynamic processor of different types of information using subunits co-ordinated by a central decision-making system.
41
Central executive (CE) definition:
The component of the WMM that co-ordinates the activities of the three subsystems in memory. It also allocates processing resources to those activities.
42
Phonological loop (PL) definition:
The component of the WMM that processes information in terms of sound. This includes both written and spoken material. It's divided into the phonological store and the articulatory process.
43
Visuo-spatial sketchpad (VSS) definition:
The component of the WMM that processes visual and spatial information in a mental space often called our 'inner eye'.
44
Episodic buffer (EB) definition:
The component of the WMM that brings together material from the other subsystems into a single memory rather than separate strands. It also provides a bridge between working memory and long-term memory.
45
The working memory model (AO1):
(WMM, Baddeley and Hitch 1974) is an explanation of how one aspect of memory (short-term memory) is organised and how it functions.
The WMM is concerned with the 'mental space that is active when we are temporarily storing and manipulating information, for example when working on an arithmetic problem or playing chess or comprehending language, etc.
The model consists of four main components, each of which is qualitatively different especially in terms of coding and capacity.
46
Central executive (AO1):
has a supervisory' role. It monitors incoming data, focuses and divides our limited attention and allocates slave systems' to tasks (see below).
The CE has a very limited processing capacity and does not store information.
47
Phonological loop (AO1):
deals with auditory information i.e. coding is acoustic) and preserves the order in which the information arrives. The PL is subdivided into:
• The phonological store, which stores the words you hear.
• The articulatory process, which allows maintenance rehearsal (repeating sounds or words in a loop' to keep them in working memory while they are needed). The capacity of this loop' is believed to be two seconds' worth of what you can say.
48
Visuo-spatial sketchpad (AO1):
second slave system is the visuo-spatial sketchpad (VSS). The VSS stores visual and/or spatial information when required. For example, if you are asked to work out how many windows there are on your house you visualise it. It also has a limited capacity, which according to Baddeley (2003) is about three or four objects (see Apply it below). Robert Logie (1995) subdivided the VSS into:
• The visual cache, which stores visual data.
• The inner scribe, which records the arrangement of objects in the visual field.
49
Episodic buffer (AO1):
third slave system is the episodic buffer (EB). This was added to the model by Baddeley in 2000. It is a temporary store for information, integrating the visual, spatial, and verbal information processed by other stores and maintaining a sense of time sequencing - basically recording events (episodes) that are happening. It can be seen as the storage component of the central executive and has a limited capacity of about four chunks (Baddeley 2012). The episodic buffer links working memory to long-term memory and wider cognitive processes such as perception.
50
Clinical evidence of WMM (AO1):
strength: support from Tim Shallice and Elizabeth
Warrington's (1970) case study of patient KF
After his brain injury, KF had poor STM ability for auditory (sound) information but could process visual information normally.
For instance his immediate recall of letters and digits was better when he read them (visual) than when they were read to him (acoustic). KF's phonological loop was damaged but his visuo-spatial sketchpad was intact.
This finding strongly supports the existence of separate visual and acoustic memory stores.
51
WMM Counterpoint (AO3):
limitation: unclear whether KF had other cognitive impairments (apart from damage to his phonological loop) which might have affected his performance on memory tasks.
KF injury was caused by a motorcycle accident. The trauma involved may have affected his cognitive performance quite apart from any brain injury.
This challenges evidence that comes from clinical studies of people with brain injuries that may have affected many different systems.
52
WMM Dual-task performance (AO3):
strength: support the separate existence of the visuo-spatial sketchpad.
When Baddeley et al's (1975) participants carried out a visual and verbal task at the same time (dual task), their performance on each was similar to when they carried out the tasks separately. But when both tasks were visual (or both were verbal), performance on both declined substantially. This is because both visual tasks compete for the same slave subsystem (VSS), whereas there is no competition when performing a verbal and visual task together.
This shows there must be a separate slave system (the VSS) that processes visual input (and one for verbal processing, the PL).
53
Nature of the central executive WMM (AO3):
limitation: lack of clarity over the nature of the central executive.
Baddeley (2003) himself recognised this when he said, 'The central executive is the most important but the least understood component of working memory. The CE needs to be more clearly specified than just being simply 'attention. For example, some psychologists believe the CE may consist of separate subcomponents.
This means that the CE is an unsatisfactory component and this challenges the integrity of the WMM.
54
Validity of the WMM (AO3):
dual-task studies support the WMM because two tasks that share a subsystem are much harder to perform together than tasks that involve separate subsystems. Therefore, there must be separate components in working memory (e.g.
VSS and PL).
However, these studies use tasks that are very unlike the tasks we perform in our everyday lives (e.g. identifying the correct order of letters such as A and B, recalling random sequences of letters). They are also carried out in highly-controlled lab conditions (e.g. where presentation of stimuli is precisely timed).
55
Interference definition:
Forgetting because one memory blocks another, causing one or both memories to be distorted or forgotten.
56
Proactive interference (PI) definition:
Forgetting occurs when older memories, already stored, disrupt the recall of newer memories. The degree of forgetting is greater when the memories are similar.
57
Retroactive interference (RI) definition:
Forgetting occurs when newer memories disrupt the recall of older memories already stored. The degree of forgetting is again greater when the memories are similar.
58
Interference theory (AO1):
Some forgetting takes place because of interference. This occurs when two pieces of information disrupt each other, resulting in forgetting of one or both, or in some distortion of memory.
Interference has been proposed mainly as an explanation for forgetting in long-term memory (LTM). Once information has reached LTM it is more-or-less permanent. Inerefore, any forgetting of LTMs is most likely because we can't get access to them even though they are available. Interference between memories makes it harder for us to locate them, and this is experienced as forgetting.
59
Types of interference (AO1):
It is very likely that the two (or more) memories that are interfering with each other were stored at different times.
- Proactive interference
- Retroactive interference
60
what is Proactive interference (PI) (AO1)?
occurs when an older memory interferes with a newer one (pro in this context means working forwards, from old to new). For example, your teacher has learned so many names in the past that she has difficulty remembering the names of her current class.
61
what is Retroactive interference (RI) (AO1)?
happens when a newer memory interferes with an older one (retro meaning working backwards). For example, your teacher has learned so many new names this year that she has difficulty remembering the names of the students last year.
62
Research on effects of similarity (AO1):
In both Pl and RI, the interference is worse when the memories (or learning) are similar, as discovered by John McGeoch and William McDonald (1931).
63
procedure for Research on effects of similarity (AO1):
McGeoch and McDonald studied retroactive interference by changing the amount of similarity between two sets of materials. Participants had to learn a list of 10 words until they could remember them with 100% accuracy. They then learned a new list.
There were six groups of participants who had to learn different types of new lists
64
different types of new lists in procedure for effects of similarity: (AO1)
Group 1: synonyms - words with the same meanings as the originals.
• Group 2: antonyms - words with the opposite meanings to the originals.
• Group 3: words unrelated to the original ones.
• Group 4: consonant syllables.
• Group 5: three-digit numbers.
• Group 6: no new list - these participants just rested (control condition).
65
Findings and conclusions on research on effects of similarity:
When the participants were asked to recall the original list of words, the most similar material (synonyms) produced the worst recall. This shows that interference is strongest when the memories are similar. The findings are shown in the graph on the left.
66
Explanation of the effects of similarity (AO1):
The reason similarity affects recall may be for one of two reasons. It could be due to PI - previously stored information makes new similar information more difficult to store. Or it could be due to RI - new information overwrites previous similar memories because of the similarity.
67
real world inference explanation for forgetting (AO3):
strength: evidence of interference effects in more everyday situations.
Alan Baddeley and Graham Hitch (1977) asked rugby players to recall the names of the teams they had played against during a rugby season. The players all played for the same time interval (over one season) but the number of intervening games varied because some players missed matches due to injury. Players who played the most games (most interference for memory) had the poorest recall.
This study shows that interference can operate in at least some real-world situations, increasing the validity of the theory.
68
counterpoint to real world inference explanations for forgetting (AO3):
Interference may cause some forgetting in everyday situations but it is unusual. This is because the conditions necessary for interference to occur are relatively rare. This is very unlike lab studies, where the high degree of control means a researcher can create ideal conditions for interference. For instance, as we have seen on this spread, two memories (or sets of learning) have to be fairly similar in order to interfere with each other.
This may happen occasionally in everyday life (eg if you were to revise similar subjects close in time), but not often.
This suggests that most forgetting may be better explained by other theories such as retrieval failure due to a lack of cues (see Interference and cues' below and next spread).
69
inference and cues (AO3):
limitation: interference is temporary and can be overcome by using cues (hints or clues to help us remember something).
Endel Tulving and Joseph Psotka (1971) gave participants lists of words organised into categories, one list at a time (participants were not told what the categories were). Recall averaged about 70% for the first list, but became progressively worse as participants learned each additional list (proactive interference). But had the words really disappeared from LTM or were they still available? At the end of the procedure the participants were given a cued recall test - they were told the names of the categories. Recall rose again to about 70%.
This shows that interference causes a temporary loss of accessibility to material that is still in LTM, a finding not predicted by interference theory.
70
support from drug studies explanations for forgetting (AO3):
strength: evidence of retrograde facilitation.
Anton Coenen and Gilles van Luijtelaar (1997) gave participants a list of words and later asked them to recall the list, assuming the intervening experiences would act as interference. They found that when a list of words was learned under the influence of the drug diazepam, recall one week later was poor (compared with a placebo control group). But when a list was learned before the drug was taken, later recall was better than placebo. So the drug actually improved (facilitated) recall of material learned beforehand. John Wixted (2004) suggests that the drug prevents new information (i.e. experienced after taking the drug reaching parts of the brain involved in processing memories, so it cannot interfere retroactively with information already stored.
This finding shows that forgetting can be due to interference - reduce the interference and you reduce the forgetting.
71
validity issues on explanations for forgetting (AO3):
Most studies supporting interference theory are lab-based, so researchers can control variables (e.g. the time between learning the material and recalling it). Control over confounding variables also means studies show a clear link between interference and forgetting.
But these studies use artificial materials and unrealistic procedures. In everyday life we often learn something and recall it much later (e.g. revising for exams).
72
Retrieval failure definition:
A form of forgetting. It occurs when we don't have the necessary cues to access memory. The memory is available but not accessible unless a suitable cue is provided.
73
Cue definition:
A 'trigger' of information that allows us to access a memory. Such cues may be meaningful or may be indirectly linked by being encoded at the time of learning. Indirect cues may be external (environmental context) or internal (mood or degree of drunkenness).
74
Retrieval failure due to the absence of cues (AO1):
The reason people forget information may be because of insuffcient cues. When information is initially placed in memory, associated cues are stored at the same time. If these cues are not available at the time of recall, it may appear as if you have forgotten the information but, in fact, this is due to retrieval failure
- not being able to access memories that are there (i.e. available).
75
Encoding specificity principle (AO1):
Endel Tulving (1983 reviewed research into retrieval failure and discovered a consistent pattern to the findings. He summarised this pattern in what he called the encoding specificity principle (ESP). This states that a cue if it is going to be helpful) has to be both (2) present at encoding (when we lean the material) and (2) present at retrieval (when we are recalling it). It follows from this that if the cues available at encoding and retrieval are different (or if cues are entirely absent at retrieval) there will be some forgetting.
Some cues are encoded at the time of learning in a meaningful way. For example, the cue 'STM'
'M of forgetting. It ave the necessary The memory is ble unless a suitable
may lead you to recall all sorts of information about short-term memory. Such cues are used in many mnemonic techniques
Other cues are also encoded at the time of learning but not in a meaningful way. We will consider
two examples of non-meaningful cues:
• Context-dependent forgetting - recall depends on external cue (e.g. weather or a place).
ation that ory. Such cues y be indirectly the time of / be external internal (mood or
• State-dependent forgetting - recall depends on internal cue (e.g. feeling upset, being drunk).
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Research on context-dependent forgetting procedure (AO1):
Duncan Godden and Alan Baddeley (1975) studied deep-sea divers who work underwater to see if training on land helped or hindered their work underwater. The divers learned a list of words either underwater or on land and then were asked to recall the words either underwater or on land.
This created four conditions:
Learn on land - recall on land.
• Learn underwater - recall on land.
• Learn on land - recall underwater.
• Learn underwater - recall underwater.
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Research on context-dependent forgetting Findings and conclusions (AO1):
In two of these conditions the environmental contexts of learning and recall matched, whereas in the other two they did not. Accurate recall was 40% lower in the non-matching conditions. They concluded that the external cues available at learning were different from the ones available at recall and this led to retrieval failure.
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Research on state-dependent forgetting procedure (AO1):
Sara Carter and Helen Cassaday (1998) gave antihistamine drugs (for treating hay fever) to their participants. The antihistamines had a mild sedative effect making the participants slightly drowsy. This creates an internal physiological state different from the 'normal' state of being awake and alain creating cour ces ito earn lists of words and passages of prose and then recall the information,
• Learn on drug - recall when on drug.
• Learn on drug - recall when not on drug.
• Learn not on drug - recall when on drug.
• Learn not on drug - recall when not on drug.
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Research on state-dependent forgetting findings (AO1):
In the conditions where there was a mismatch between internal state at learning and recall, performance on the memory test was significantly worse. So when the cues are absent (for example, you are drowsy when recalling information but had been alert learning it) then there is more forgetting
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explanations for forgetting Real-world application (AO3):
strength: retrieval cues can help to overcome some forgetting in everyday situations.
Although cues may not have a very strong effect on forgetting, Baddeley suggests they are still worth paying attention to. For instance, we have probably all had the experience of being in one room and thinking I must go and get such-and-such item from another room. You go to the other room only to forget what it was you wanted. But the moment you go back to the first room, you remember again. When we have trouble remembering something, it is probably worth making the effort to recall the environment in which you learned it first.
This shows how research can remind us of strategies we use in the real
world to improve our recall.
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explanations for forgetting Research support (AO3):
strength: range of research that supports the retrieval failure explanation.
The studies by Godden and Baddeley and Carter and Cassaday (facing page) are just two examples because they show that a lack of relevant cues at recall can lead to context-dependent and state-dependent forgetting in everyday life. Memory researchers Michael Eysenck and Mark Keane (2010) argue that retrieval failure is perhaps the main reason for forgetting from LTM.
This evidence shows that retrieval failure occurs in real-world situations as
well as in the highly controlled conditions of the lab.
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explanations for forgetting counterpoint (AO3):
Baddeley (1997) argues that context effects are actually not very strong, especially in everyday life. Different contexts have to be very different indeed before an effect is seen. For example, it would be hard to find an environment as different from land as underwater (Godden and Baddeley). In contrast, learning something in one room and recalling it in another is unlikely to result in much forgetting because these environments are generally not different enough.
This means that retrieval failure due to lack of contextual cues may not
actually explain much everyday forgetting.
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Recall versus recognition (AO3):
limitation: context effects may depend substantially on the type of memory being tested.
Godden and Baddeley (1980) replicated their underwater experiment but used a recognition test instead of recall - participants had to say whether they recognised a word read to them from a list, instead of retrieving it for themselves. When recognition was tested there was no context-dependent effect, performance was the same in all four conditions.
This suggests that retrieval failure is a limited explanation for forgetting because it only applies when a person has to recall information rather than recognise it.
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Problems with the ESP (AO3):
There is a lot of evidence that forgetting takes place when there is a mismatch (or absence) of encoding and retrieval cues (Tulving's encoding specificity principle).
However, is it possible to independently establish whether a cue has been encoded or not? The reasoning is circular and based on assumptions. In an experiment, if a cue did not produce recall we assume it cannot have been encoded. If the cue did produce recall, we assume it must have been encoded.
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Eyewitness testimony (EWT) definition:
The ability of people to remember the details of events, such as accidents and crimes, which they themselves have observed. Accuracy of EWT can be affected by factors such as misleading information and anxiety.
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Misleading information definition:
Incorrect information given to an eyewitness usually after the event (hence often called
'post-event information). It can take many forms, such as leading questions and post-event discussion between co-witnesses and/or other people.
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Leading question definition:
A question which, because of the way it is phrased, suggests a certain answer. For example: 'Was the knife in his left hand?' leads a person to think that's where the knife was.
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Post-event discussion (PED) definition:
occurs when there is more than one witness to an event. Witnesses may discuss what they have seen with co-witnesses or with other people.
This may influence the accuracy of each witness's recall of the event.
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Research on leading questions (AO1):
When you are asked a question, the wording of the question may lead (or mislead) you to give a certain answer. This is a particular issue for eyewitness testimony (EWT) because police questions may direct a witness to give a particular answer. In the experiment below words such as smashed or bumped were used to suggest the speed of the car.
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Misleading information research procedure (AO1):
Elizabeth Loftus and John Palmer (1974) arranged for 45 participants (students) to watch film clips of car accidents and then asked them questions about the accident. In the critical question (a leading question or also called misleading information) participants were asked to describe how fast the cars were travelling: About how fast were the cars going when they hit each other?' There were five groups of participants and each group was given a different verb in the critical question. One group had the verb hit, the others had contacted, bumped, collided, smashed.
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Research on leading questions findings (AO1):
The mean estimated speed was calculated for each participant group. The verb contacted resulted in a mean estimated speed of 31.8 mph. For the verb smashed, the mean was 40.5 mph (full findings on facing page). The leading question biased the eyewitness's recall of an event.
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Why do leading questions affect EWT? (AO1):
The response-bias explanation suggests that the wording of the question has no real effect on the participants' memories, but just influences how they decide to answer. When a participant gets a leading question using the word smashed, this encourages them to choose a higher speed estimate.
Loftus and Palmer (1974) conducted a second experiment that supported the substitution explanation, which proposes that the wording of a leading question changes the participants memory of the film clip. This was shown because participants who originally heard smashed were later more likely to report seeing broken glass (there was none) than those who heard hit. The critical verb altered their memory of the incident.
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Research on post-event discussion (AO1):
Eyewitnesses to a crime may sometimes discuss their experiences and memories with each other. The following experiment explores the effects of such post-event discussion (PED).
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Research on post-event discussion procedure (AO1):
Fiona Gabbert et al. (2003) studied participants in pairs. Each participant watched a video of the same crime, but filmed from different points of view. This meant that each participant could see elements in the event that the other could not. For example, only one of the participants could see the title of a book being carried by a young woman.
Both participants then discussed what they had seen before individually completing a test of recall.
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Research on post-event discussion findings (AO1):
The researchers found that 71% of the participants mistakenly recalled aspects of the event that they did not see in the video but had picked up in the discussion. The corresponding figure in a control group, where there was no discussion, was 0%. This was evidence of memory conformity.
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Why does post-event discussion affect EWT? (AO1):
One explanation is memory contamination. When co-witnesses to a crime discuss it with each other, their eyewitness testimonies may become altered or distorted. This is because they combine (mis)information from other witnesses with their own memories.
Another explanation is memory conformity. Gabbert et al. concluded that witnesses often go along with each other, either to win social approval or because they believe the other witnesses are right and they are wrong. Unlike with memory contamination, the actual memory is unchanged.
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misleading information Real-world application (AO1):
strength: has important practical uses in the criminal justice system.
The consequences of inaccurate EWT can be very serious. Loftus (1975)
believes that leading questions can have such a distorting effect on memory that police officers need to be very careful about how they phrase their questions when interviewing eyewitnesses. Psychologists are sometimes asked to act as expert witnesses in court trials and explain the limits of EWT to juries.
This shows that psychologists can help to improve the way the legal system works, especially by protecting innocent people from faulty convictions based on unreliable EWT.
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misleading information Counterpoint (AO3):
the practical applications of EWT may be affected by issues with research. For instance, Loftus and Palmer's participants watched film clips in a lab, a very different experience from witnessing a real event (e.g. less stressful). Also, Rachel Foster et al. (1994) point out that what eyewitnesses remember has important consequences in the real world, but participants' responses in research do not matter in the same way (so research participants are less motivated to be accurate).
This suggests that researchers such as Loftus are too pessimistic about the effects of misleading information - EWT may be more dependable than many studies suggest.
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Evidence against substitution (AO3):
limitation: EWT is more accurate for some aspects of an event than for others.
Rachel Sutherland and Harlene Hayne (2001) showed participants a video clip. When participants were later asked misleading questions, their recall was more accurate for central details of the event than for peripheral ones. Presumably the participants' attention was focused on central features of the event and these memories were relatively resistant to misleading information.
This suggests that the original memories for central details survived and were not distorted, an outcome that is not predicted by the substitution explanation.
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Evidence challenging memory conformity (AO3):
limitation: evidence that post-event discussion actually alters EWT
Elin Skagerberg and Daniel Wright (2008) showed their participants film clips. There were two versions, e.g. a mugger's hair was dark brown in one but light brown in the other. Participants discussed the clips in pairs, each having seen different versions. They often did not report what they had seen in the clips or what they had heard from the co-witness, but a 'blend' of the two (e.g. a common answer to the hair question was not light brown' or dark brown' but 'medium brown').
This suggests that the memory itself is distorted through contamination by misleading post-event discussion, rather than the result of memory conformity.
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misleading information Demand characteristics (AO3):
Lab studies have identified misleading information as a cause of inaccurate EWT, partly by being able to control variables.
But Maria Zaragoza and Michael McCloskey (1989) argue that many answers given by participants in lab studies are due to demand characteristics. Participants usually want to be helpful and not let the researcher down. So they guess when they are asked a question they don't know the answer to.
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Anxiety definition:
A state of emotional and physical arousal. The emotions include having worried thoughts and feelings of tension. Physical changes include an increased heart rate and sweatiness. Anxiety is a normal reaction to stressful situations, but it can affect the accuracy and detail of eyewitness testimony.
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Weapon focus effect case study (AO1):
The study by Johnson and Scott demonstrated the weapon focus effect. Research shows that the anxiety of seeing a weapon focuses all your attention on the weapon and this means you won't be able to recall much else.
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The effects of anxiety (AO1):
Anxiety has strong emotional and physical effects. But it is not clear whether these effects make eyewitness recall better or worse. Research supports both possibilities.
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Anxiety has a negative effect on recall (weapon focus) (AO1):
- creates physiological arousal in the body which prevents us paying attention to important cues, so recall is worse. One approach to studying anxiety and eyewitness testimony (EWT) is to look at the effect of the presence of a weapon which creates anxiety. This leads to a focus on the weapon, reducing a witness's recall for other details of the event.
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weapon focus procedure (AO1):
Craig Johnson and William Scott (1976) did research on this. Their participants believed they were taking part in a lab study. While seated in a waiting room participants in the low-anxiety condition heard a casual conversation in the next room and then saw a man walk past them carrying a pen and with grease on his hands. Other participants overheard a heated argument, accompanied by the sound of breaking glass. A man walked out of the room, holding a knife covered in blood. This was the high-anxiety condition.
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weapon focus Findings and conclusion (AO1):
participants later picked out the man from a set of 50 photos, 49% who had seen the man carrying the pen were able to identify him. The corresponding figure for the participants who had seen the man holding the blood-covered knife was 33%. The tunnel theory of memory argues that people have enhanced memory for central events. Weapon focus as a result of anxiety can have this effect.
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Anxiety has a positive effect on recall (AO1):
witnessing a stressful event creates anxiety through physiological arousal within the body. The fight or flight response is triggered, increasing alertness. This may improve memory for the event as we become more aware of cues in the situation.
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anxiety effect on recall procedure:
John Yuille and Judith Cutshall (1986) conducted a study of an actual shooting in a gun shop in Vancouver, Canada. The shop owner shot a thief dead. There were 21 witnesses - 13 took part in the study. They were interviewed four to five months after the incident and these interviews were compared with the original police interviews at the time of the shooting. Accuracy was determined by the number of details reported in each account. The witnesses were also asked to rate how stressed they had felt at the time of the incident (on a 7-point scale) and whether they had any emotional problems since the event (e.g. sleeplessness).
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anxiety effect on recall Findings and conclusion (AO1):
witnesses were very accurate in their accounts and there was little change in the amount recalled or accuracy after five months - though some details were less accurate, such as recollection of the colour of items and age/height/weight estimates. Those participants who reported the highest levels of stress were most accurate (about 88% compared to 75% for the less-stressed group). This suggests that anxiety does not have a detrimental effect on the accuracy of eyewitness memory in a real-world context and may even enhance it.
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anxiety Explaining the contradictory findings (AO1):
Robert Yerkes and John Dodson (1908) the relationship between emotional arousal and performance looks like an inverted U' (see graph below).
Kenneth Deffenbacher (1983) reviewed 21 studies of EWT and noted contradictory findings on the effects of anxiety. He used the Yerkes-Dodson Law to explain the findings. When we witness a crime/accident we become emotionally and physiologically aroused. That is, we experience anxiety (emotional) as well as physiological changes in our body (the fight or flight response). Lower levels of anxiety/arousal produce lower levels of recall accuracy, and then memory becomes more accurate as the level of anxiety/arousal increases. However, there is an optimal level of anxiety, which is the point of maximum accuracy. If a person (or eyewitness) experiences any more arousal, then their recall suffers a drastic decline.
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Unusualness not anxiety (AO1):
limitation: Johnson and Scott is that it may not have tested anxiety.
The reason participants focused on the weapon may be because they were surprised at what they saw rather than scared. Kerri Pickel (1998) conducted an experiment using scissors, a handgun, a wallet or a raw chicken as the hand-held items in a hairdressing salon video (where scissors would be high anxiety, low unusualness). Eyewitness accuracy was significantly poorer in the high unusualness conditions (chicken and handgun).
- so weapon focus effect is due to unusualness rather than anxiety/threat and therefore tells us nothing specifically about the effects of anxiety on EWT.
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Support for negative effects (AO3):
strength: evidence supporting the view that anxiety has a negative effect on the accuracy of recall.
Tim Valentine and Jan Mesout (2009, see right) supports the research on weapon focus, finding negative effects on recall. The researchers used an objective measure (heart rate) to divide participants into high- and low-anxiety groups. In this study anxiety clearly disrupted the participants' ability to recall details about the actor in the London Dungeon's Labyrinth.
This suggests that a high level of anxiety does have a negative effect on the immediate eyewitness recall of a stressful event.
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Support for positive effects (AO3):
strength: evidence showing that anxiety can have positive effects on the accuracy of recall.
Sven-Ake Christianson and Birgitta Hübinette (1993) interviewed 58 witnesses to actual bank robberies in Sweden. Some of the witnesses were directly involved (e.g. bank workers) and some were indirectly involved (e.g. bystanders). The researchers assumed that those directly involved would experience the most anxiety. It was found that recall was more than 75% accurate across all witnesses. The direct victims (most anxious were even more accurate.
These findings from actual crimes confirm that anxiety does not reduce the accuracy of recall for eyewitnesses and may even enhance it.
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anxiety Counterpoint (AO3):
Christianson and Hübinette interviewed their participants several months after the event (four to 15 months). The researchers therefore had no control over what happened to their participants in the intervening time (e.g. post-event discussions). The effects of anxiety may have been overwhelmed by these other factors and impossible to assess by the time the participants were interviewed Therefore it is possible that a lack of control over confounding variables may be responsible for these findings, invalidating their support.
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Problems with inverted-U theory (AO3):
a reasonable explanation of the contradictory findings linking anxiety with both increased and decreased eyewitness recall.
On the other hand it ignores the fact that anxiety has many elements - cognitive, behavioural, emotional and physical. It focuses on just the last of these (physical arousal) and assumes this is the only aspect linked to EWT. But the way we think about the stressful situation (i.e. cognitive) may also be important.
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Cognitive interview definition:
A method of interviewing eyewitnesses to help them retrieve more accurate memories. It uses four main techniques, all based on evidence-based psychological knowledge of human memory - report everything, reinstate the context, reverse the order and change perspective.
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The cognitive interview (AO1):
Ronald Fisher and Edward Geiselman 1992) argued that eyewitness testimony could be improved if the police used better techniques when interviewing witnesses. Fisher and Geiselman recommended that such techniques should be based on psychological insights into how memory works, and called these techniques collectively the cognitive interview (CI) to indicate its foundation in cognitive psychology.
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cognitive interview main techniques (AO1):
1. report everything
2. Reinstate the context
3. Reverse the order
4. Change perspective
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Report everything (AO1):
Witnesses are encouraged to include every single detail of the event, even though it may seem irrelevant or the witness doesn't feel confident about it. Seemingly trivial details may be important and, moreover, they may trigger other important memories.
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Reinstate the context (AO1):
The witness should return to the original crime scene in their mind' and imagine the environment (such as what the weather was like, what they could see) and their emotions (such as whether they were happy or bored). This is related to context-dependent forgetting
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Reverse the order (AO1):
Events should be recalled in a different order from the original sequence, for example, from the final point back to the beginning, or from the middle to the beginning.
This is done to prevent people reporting their expectations of how the event must have happened rather than reporting the actual events. It also prevents dishonesty (it's harder for people to produce an untruthful account if they have to reverse it).
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Change perspective (AO1):
Witnesses should recall the incident from other peoples perspectives.
e.g how it would have appeared to other witnesses or to the perpetrator. This again is done to disrupt the effect of expectations and also the effect of schema on recall. The schema you have for a particular setting (such as going into a Shop) generate expectations of what would have happened and it is the schema that is recalled rather than what actually happened.
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The enhanced cognitive interview (ECI) (AO1):
Fisher et al. (1987) developed some additional elements of the Cl to focus on the social dynamics of the interaction. For example, the interviewer needs to know when to establish eye contact and when to relinquish it. The enhanced Cl also includes ideas such as reducing eyewitness anxiety, minimising distractions, getting the witness to speak slowly and asking open-ended questions.
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Support for the effectiveness of the Cl (AO3):
strength: evidence that it works
meta-analysis by Günter Köhnken et al.
1999) combined data from 55 studies comparing the Cl and the ECI) with the standard police interview. The Cl gave an average 41% increase in accurate information compared with the standard interview. Only four studies in the analysis showed no difference between the types of interview.
This shows that the Cl is an effective technique in helping witnesses to recall information that is stored in memory (available) but not immediately accessible.
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Counterpoint for CI (AO3):
Köhnken et al. also found an increase in the amount of inaccurate information recalled by participants. This was a particular issue in the ECl, which produced more incorrect details than the Cl. Cognitive interviews may sacrifice quality of EWT (i.e. accuracy) in favour of quantity (amount of details).
This means that police officers should treat eyewitness
evidence from Cls/ECIs with caution.
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Some elements may be more useful (AO3):
limitation of original CI: not all of its elements are equally effective or useful.
Rebecca Milne and Ray Bull (2002) found that each of the four techniques used alone produced more information than the standard police interview. But they also found that using a combination of report everything and reinstate the context produced better recall than any of the other elements or combination of them. This confirmed police officers' suspicions that some aspects of the Cl are more useful than others.
This casts some doubt on the credibility of the overall cognitive interview.
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The Cl is time-consuming (AO3):
limitation: police officers may be reluctant to use the Cl because it takes more time and training than the standard police interview.
For example, more time is needed to establish rapport with a witness and allow them to relax. The Cl also requires special training and many forces do not have the resources to provide more than a few hours (Kebbell and Wagstaff 1997).
This suggests that the complete Cl as it exists is not a realistic method for police officers to use and (as in the point above) it might be better to focus on just a few key elements.
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Variations of the Cl (AO3):
Police forces have taken a pick and mix' approach to the various techniques in the Cl. This means it is hard to compare the effectiveness of different approaches in research studies.
On the other hand, this 'pick and mix' approach is more flexible. It means that individuals can develop their own approach according to what works best for them.
