Memory Flashcards
(132 cards)
1
Q
Define memory
A
The mental process used to encode, store and retrieve information. It is useful to distinguish between 2 types of memory- STM and LTM.
2
Q
What is capacity
A
The amount of information that can be held in a memory store
3
Q
What is the capacity of STM
A
7 +/- 2 units
4
Q
What is the capacity of LTM
A
Impossible to test- unlimited
5
Q
Which researchers investigated the capacity of STM
A
Jacobs (1887) and Miller (1956)
6
Q
Describe the work of Jacobs on STM
A
Digit Span Technique:
- Laboratory experiment
- Ask Pp to remember and repeat lists of items in increasing length
- Pp had to recall lists of digits or letters in the same order they were presented- serial recall
- Pace matched to a metronome
7
Q
Describe the findings/conclusions of Jacobs on STM
A
- average STM span was between 5 and 9 digits
- Digits recalled better than letters (9.3 items vs 7.3)
- digit span increased with age- 6.6 for 8-year-old children and 8.6 for 19-year-olds
- Capacity of STM is 7 +/- 2 units
- individual differences such as age increase digit span
8
Q
Describe the work and findings of Miller on STM
A
- the amount of info STM can hold can be increased by chunking- organising items of information into groups to make most of STM
9
Q
What are the limitations of research on the capacity of STM, include a counterargument
A
- Lab study- lacks ecological validity- artificial setting
- lacks mundane realism- not something we would do in everyday life
- Jacobs is an old study- could have been confounding variables distraction- however, findings confirmed by well-controlled studies later - repeatable- Eg. Bopp and Verhaegan 2005)
- Cowan (2001) reviewed other research and concluded STM capacity is only about 4 +/- 1 chunk- lower end more accurate?
10
Q
Who investigated the duration of STM
A
Brown; Peterson and Peterson
11
Q
What were the aims of Brown; Peterson and Petersons experiment
A
- To investigate the duration of STM and effects of rehearsal
- Used the Brown-Peterson technique- a method of measuring STM while reducing rehearsal
12
Q
What was the procedure for Brown; Peterson and Petersons study
A
- PPs briefly shown a trigram of consonants, eg. VGT, FCN
- Then asked to count backwards in 3s from a given number
- after intervals of 3,6,9,12,15 or 18 seconds, participants were asked to recall trigram
13
Q
What were the findings from Brown; Peterson and Petersons study
A
- PPs able to recall 80% of trigrams after 3-second interval
- 50% after 6 seconds
After 18 seconds dropped to under 10%
14
Q
What were the conclusions from Brown; Peterson and Petersons study
A
- Info in STM is lost quickly if rehearsal is prevented
- Became known as Brown-Peterson effect- the rapid loss of info in STM if rehearsal is prevented
15
Q
Explain 3 positives from Brown; Peterson and Petersons study
A
- Important practical applications- improve peoples memory from rehearsal- findings can be used to improve lives
- Adds support to their of two memory stores- as counting backwards prevents rehearsal and passing to LTM store- research important contribution to our understanding of memory
- Highly controlled- studies carried out in labs so extraneous variables controlled- reliable and valid
16
Q
Explain limitations of Brown; Peterson and Petersons study
A
- Lacks ecological validity- lab study- cant generalise results to other situations
- Lacks mundane realism- not something you’d do in everyday life- lacks external validity
17
Q
Who investigated the duration of LTM
A
Bahrick et al (1975)
18
Q
What was the aim of Bahrick et al study
A
- measure duration of LTM
- Demonstrate the existence of very long term memory
- Testing memory of real-life information
19
Q
What was the procedure of Bahrick et al study
A
-40- student Pp of different ages Using old school yearbook, Pp asked to: - Free recall of classmates - photo recognition - name recognition - name and photo matching
20
Q
What was the findings of Bahrick et al study
A
- After up to 34 years, Pp could remember up to 90%
- After 48 years declined to 70%
- free recall less accurate- 60% after 15 years, 30% after 48 years
21
Q
What was the conclusions of Bahrick et al study
A
- LTM has potential to last a lifetime
- People have very long term memories that are very accurate
22
Q
What were the positives from Bahrick et als study
A
- good mundane realism- the recall of peoples names and faces something we do in everyday life- makes it possible to generalise findings to other situations- when meaningless recall results lower- eg. Shepard 1967
- adds support to the theory of 2 memory stores- people recalling the names from LTM which appears to have a long duration- good understanding of how human memory works
- highly controlled- lab setting- researcher could control variables- findings more likely to be reliable and valid
23
Q
Define coding
A
- The way in which memory is changed and formatted to be stored in the various different memory stores
24
Q
Who investigated coding
A
Baddeley (1966)
25
What was the aim of Baddelys investigation
To explore the effect of acoustic and semantic coding in STM and LTM
26
What was the procedure of Baddelys investigation
In STM study, Pp asked to immediately recall in serial order a list of 5 words taken from the following categories:
- acoustically similar
- acoustically different
- Semantically similar
- Semantically dissimilar
In LTM study each list extended to 10 and recall was tested after 20 mins
27
What were the findings of Baddelys investigation
- in STM acoustically similar harder than dissimilar, but semantics had little effect
- in LTM, recall of semantically similar words much worse than dissimilar, acoustics little effect
28
What were the conclusions of Baddelys investigation
- STM relies on acoustic coding
| - LTM relies on semantic coding
29
Evaluate Baddelys study
- 20 mins- may not have been effectively testing LTM
- STM may not be exclusively acoustic- when Pp had visual task to complete an verbal rehearsal prevented, Pps were able to use visual codes to recall info (Brandimote et al 1992)
- meaningless stimuli- lacks mudane realism- not much learnt about coding for memory tasks in everyday life- eg. might actually use semantic STM
- However did identify clear difference between 2 memory stores- acoustic vs semnatic repeatable- helped lead to Multi store model of memory
30
what is the duration of STM
18-30 secs
31
What did Atkinson and Shiffrin (1968) conclude
Memory is made up of a series of stores and can be described memory as information flowing through a linear system. It can be described as an information processing model, with input, processing ad output.
32
Describe the transfers and stores of the multistore model of memory
Input --> SENSORY REGISTER
- -Attention/transfer--> STM
- -rehearsal (maintenance loop to keep, prolonged to transfer)--> LTM
- -retrieval--> STM
- -Response--> leave (remembering)
33
What is the capacity, duration and coding of the sensory register
- unlimited
- 250 milliseconds
- Modality specific
34
What is the capacity, duration and coding of STM
- 7 +/- 2 units
- 18- 30 secs
- Acoustic
35
What is the capacity, duration and coding of LTM
- Unlimited
- potential for lifetime
- semantic
36
Define the multi-store model of memory
A representation of how memory works in terms of 3 stores- sensory register, STM and LTM. Also describes how info is transferred from one store to another, what makes some memories and some disappear
37
Describe the use and coding of the sensory register
- all stimuli from the environment pass into the sensory register
- composes of several registers- one for each of the 5 senses
Modality specific coding- eg. visual = iconic memory, sound = echoic-n others for touch, taste and smell
38
Describe maintenance rehearsal
Occurs when we repeat material to ourselves over and over again- we can keep info in our STM if we repeat it over and over if long enough, transferred to LTM
39
What is elaborative rehearsal
Involves more meaningful analysis, (eg. images, thinking, associations) of info and leads to better recall- eg. giving words meaning or linking with previous knowledge.
40
Who studies the sensory memory for vision
Sperling (1960)
41
Describe Sperlings Studies
- studied the iconic store in sensory memory using a tachistoscope- can flash pictoral stimuli onto a blank screen for very brief instances
- Asked Pp to remember as many letters as they could from grid of 12 symbols displayed for 50 ms
- could only recall around 4 before grid faded from sensory memory, but reported seeing more than had time to report
42
How did Sperling use his study to measure capacity
- devised partial report technique
- trained Pps to distinguish between 3 tones- high, medium or low tone
- then exposed grid for same amount of time, when disappeared a tone corresponded to row of 4 letters- top high tone etc
- In the partial report condition, recall was on average just over 3 out of 4 symbols from any row
- suggests iconic store can retain approximately 76% of all data recieved
43
How did Sperling use his study to measure duration
If there was a delay between the presentation of the grid and tone, more and more info was lost- only 50% available after 0.3 sec delay, only 33% after 1 sec
44
What is an example of research to support the MSM
Glanzer & Cunitz
45
What was the procedure and findings of Glanzer & Cunitz
Procedure:
- Pp presented with list of words and asked to immediately recall
Findings:
- Words at beginning of list are recalled (primacy effects)
- Words at end of list also recalled (recency effect)
- Words in middle forgotten (asymtote)
46
Explain the findings of Glanzer & Cunitz in terms of the MSM
- pay attention ar first - SR-STM- and have a chance to rehearse -LTM
- by middle, capacity slots in STM filled- can't remember any more without time to rehearse previous
- at end, still in STM
47
Evaluate the MSM
Strengths: -research indicates differnce between STM and LTM- different in terms of capacity, duration and encoding- 7+- 2 units vs unlimited (Jacobs)- empirical support for muti stire model adding wider academic credibility, however studies differentiating lack mundane realism- we recall names, faces, stories etc all the time- studies used things with no meaning- not applicable to real life?
Case of HM
Weakness- Model is too simplistic in that other models of both STM and LTM propose that both STM and LTM may be provided in to a number of different stores- working memory model (Baddeley and Hitch 1974) suggests STM more accurately represented using series of different stores which handle different modalities (acoustic and visual), Tulving (1985) suggests LTM divided into episodic, semantic and procedural memory- MSM doesn't provide complete explanation
Cases of KF and Clive Wearing
48
Describe the case study of HM
Henry Molasion
- very severe epileptic
- brain surgeon removed hippocampi to try and control seizures- controlled epilepsy but left him with severe memory impairment
- global amnesia for new material- lost ability to form any new LTMs- names, songs, places
- still remembered things before the surgery
- however could learn new motor skills- tracing star in mirror improve, using a walking frame- however subconscious level
49
Relate the case study of HM to the MSM
- supports 2 types of memory- has STM but no LTM- shows different duration, capacities etc
- however, shows simplistic- shows different procedural vs episodic LTM- MSM doesn't account for motor memory
50
Describe the case study of Clive Wearing
- Viral encephalitis affected the hippocampus
| - lost all LTM- only has STM- sees only what's in front of him then forgets
51
relate Clive Wearing to the MSM
- for- 2 separate stores
| - against- can still play music, sing an conduct- procedural memory still intact
52
Describe the case study of KF
Shallice and Warrington (1970)
- difficulties processing verbal information, but normal ability to process visual information- amnesia- couldn't recall digits when read out loud, but could when read himself
53
Relate KF to the MSM
- disproves- different types of STM processing info
54
What are the benefits and limitations of using case studies
- strengths- provides detailed information, insight for further research, permits investigation in otherwise unethical situations
- Limitations- difficult to replicate, time consuming, hard to generalise, researcher bias
55
What are the 2 categories of Long Term memory, and what are the 3 types within these
Declarative- semantic and episodic
Implicit- Procedural
56
Describe episodic memory
- Ability to recall episodes of your life
- Time-stamped events- remember when and what happened
- How events relate to each other in time
- Memory of a single episode will include many elements- places, objects, behaviours etc- interwoven to produce single memory
- Conscious effort to recall- quickly but aware of searching memory
Examples- Birthday parties, visits to the doctor etc
57
Describe semantic memory
- shared knowledge of the world
- mix between encyclopedia and dictionary
- not time-stamped- don't remember when we learnt
- Concepts- animals, music etc
- Less personal- shared knowledge
- Constantly being added to
- Tulving said less vulnerable to distortion and forgetting
Examples- Capital cities, meaning of words
58
Describe semantic memory
- shared knowledge of the world
- mix between encyclopedia and dictionary
- not time-stamped- don't remember when we learnt
- Concepts- animals, music etc
- Less personal- shared knowledge
- Constantly being added to
- Tulving said less vulnerable to distortion and forgetting
Examples- Capital cities, meaning of words
59
Describe procedural memory
- memory of actions or skills- how we do things
- Eventually recall without much awareness or effort
- Hard to explain to someone else- can become more difficult as you attempt to do so
Examples- driving car, riding bike
60
Who first came up with the idea of different stores of LTM
Tulving- 1985
61
Which regions of the brain are involved with different types of LTM
Prefrontal cortex- memory involving sequence of events, but not events them selves
Amygdala- encodes emotional aspects of memory
Cerebellum- memories involving movement
Hippocampus- encodes and transfers new explicit memories to LTM
62
What are strenths of the multiple LTM stores model
- Clinical evidence- HM and Clive Wearing- Episodic severely impaired in both, semantic still partial in Clive, Both still had procedural memory- Clive playing music, HM improving at tracing a star in the mirror but couldn't remember doing it- both still walk and talk
Real-world application- allows psychologists to help people with memory problems. Age-related memory loss- seems t be mainly episodic- especially from long ago. Belleville- intervention to improve episodic memories in older people- trained PPs performed better on test on episodic memory than control group- shows distinguishing between types of LTM enable specific treatments to be developed
63
What are limitation of the multiple stores of LTM model
- while studying those with brain injury can help us understand how normal memory is supposed to work, there is a lack of control variables- unexpected injuries- no way of controlling what happened before or during, no knowledge of memory before- hard to judge how much wore after- limits how much clinical studies can tell us
- Conflicting neuroimaging evidence- Buckner and Petersen reviewed the evidence regarding the location of semantic and epesodic memory- concluded semantic memory located on left side of prefrontal cortex, episodic on right. However either research links the left prefrontal cortex with encoding episodic memories and right with episodic retrieval- Tulving- challenges any neurophysiological evidence to support types of memory as poor agreement
64
What has been found more recently about the types of LTM
Tulving (2002)- episodic memory is a specialised subcategory of semantic memory- people with amnesia have functioning semantic memory but damaged episodic memory, not possible to have functioning episodic memory with damaged semantic memory
However, Hodges and Patterson (2007) found some people with Alzheimers could form new episodic but not semantic
65
What is the second model of memory, who proposed it and when
Working memory model- Baddeley and Hitch- 1974
66
define the working model of memory
A representation of short term memory suggesting that it is a dynamic processor of different types of information using subunits coordinated by a central decision-making system. It is concerned with the mental space that is active when we are temporarily storing and manipulating information when completing an activity. The model consists of four main components, each of which is qualitatively different especially in terms of coding and capacity.
67
What are the elements of the working memory model
The central executive, the phonological loop, the visuospatial sketch pad, episodic buffer, episodic long term memory
68
Describe the central executive
- Have a supervisory role- monitors incoming data, focuses and divides our limited attention and allocates subsystems to tasks.
- Has a very limited capacity, is modality free.
- allocates attention and directs the operation of the two slave systems in overall control of how resources are allocated when we encode incoming information
69
Describe the phonological loop
- responsible for acoustic encoding- deals with auditory information
- preserves the order in which auditory information arrives
- time based capaciti- 2 seconds
Loop-
- phonological store- inner ear- stores words you hear
- articulatory control system- inner voice- allows maintenance rehearsal
70
Describe the visuo-spatial sketch pad
- inner eye
- stores visual and/or spatial information when required
- processes data visually, specialised for acoustic and/or visual encoding
- can hold 4-5 pieces
71
what did Baddeley add onto the model later on, and when
episodic buffer- 2000
72
describe the episodic buffer
- temporary store of information, integrating the visual, spatial and verbal information processed by other stores, and maintaining a sense of time sequencing
- assumed to have links to long term memory and semantical meaning
- capacity of about four chunks (Baddeley, 2012)
73
what are the strengths of the working model of memory
- Neuroimaging evidence- Paulescu et al (1993)- used PET scans- showed very different areas of the brain being used in visual (posterior regions) and auditory (central regions) tasks. Provides strong supporting evidence- adds to wider academic credibility of explanation.
- Evidence from dual-task research- Baddleley and Hithch (1976)- when visual and verbal at same time, similar performance to when separate. When both visual/verbal, performance declined substantially. Both tasks using sam eslavesystem- must be 2x separate. explains why we can o some tasks at same time if they involve different systems but struggle with others if use the same.
- Clinical evidence- KF (Shallice and Warrington, 1970)- amnesia after brain injury- poor STM for auditory processing but could process visual information normally. E.g. recall of didgits/letter better when read himself than when read to him. Phonological loop damaged but VS sketchpad intact. Supports the existence of separate visual and acoustic memory stores.
74
What are the weaknesses of the WMM
- much of research evidence lacks ecological validity- often lab based- lacking in mundane realism e.g. serial recall- difficult to apply to real life
- vague function of central executive- little known about it- no detail of how info transferred into 3 slave systems- Baddeley- "Most important but the least understood"- some psychologists think there may be subsystems- oversimplistic, unsatisfactory component- challenges integrity of WMM
- challenge of clinical evidence- unclear of KF had other cognitive impairments- may have affected performance on memory tasks- trauma from accident may have affected cognitive performance apart from brain injury- challenges evidence from clinical studies as people's brain injuries may have affected many different systems.
75
Brief comparison plan of WMM and MSM
Similarities:
- both have evidence to support- Baddeley MSM, Dual task research WMM
- Borth criticised for simplicity- CE of WMM, lack of different types of STM/LTM MSM
Differences:
- MSM loos at sensory, STM, LTM- WMM only processes involved with STM
- MSM sees STM as passive store, WMM sees as active processing system (explain)
- MSM says STM single store, WMM says several stires- expand- can account for 2 STM
tasks simultaneously and KF clinical evidence
76
What are 2 explanations for forgetting
- interferrence
| - retrieval failure
77
What is interference
forgetting because one memory blocks another, causing one or both memories to be distorted or forgotten. More likely to happen if the memories are similar.
78
What are 2 types of interference, describe them
- proactive- when previous, already stored memory/ learning interferes with recall/formation of new/current memories
- retroactive- occurs when newer memories disrupt the recall of older memories ready stored.
Both greater when memories are similar.
79
List research done into interference
- Underwood and Postman
| - Baddeley and Hitch
80
What was the aim of underwood and postmans research
To find out if new learning interferes with previous learning
81
What was the procedure of underwood and postmans research
- PPs divided into 2 groups
- Group A asked to learn a list of word from word pairs- e.g. cat-tree, then asked to learn second list where second work was different- e.g. cat-grass
- group B only asked to learn first list
- both asked to recall first list
82
What were the findings/ conclusions of underwood and postmans research
- group B recall of first list more accurate than group A
| - Demonstrates retroactive interference- the new words had caused the earlier to be forgotten
83
Evaluate underwood and postmans research
- poor mundane realism
- lacks ecological validity
- crafted to have optimal conditions for interferrence- similar words- not often in everyday life- e.g. revising similar subjects, but not often
- Tulving and Psotka- list of words organised into 2 categories, one list at a time without knowing category. Recall around 70% for first list but got progressively worse after each list- interference. However, once told category, recall rose again to around 70%- starting point. Always in LTM? interference jus causes temporary loss- theory not predicted by interference theory
- good controll as in lab- can limit confounding variables- clear link between interference and forgetting
84
Summarise Baddeley and Hitch's study of interference (1977)
- asked rugby players to recall names of teams recently played
- injury/susoensions varied times between last games as missed some- variety of weeks-months since last game
- players who played most games had porrest recall
- shows probability of correct recall nit dependent on passage of time as the decay theorywould predict, but on the number of intervening games- interference has greater effect than time
85
What are the benefits of research into interference
- good controll as in lab- can limit confounding variables- clear link between interference and forgetting
- Both take into account the nature of the material. Similarity effects interference- names of game similar type of memory, first list in pair the same.
- support from drug studies- Coenen and Luijtelaar gave Pp list of words, lar asked to recall- assumed intervening experiences would act as interference. Found when list of words learnt under influence of diazepam, recall after 1 week was worse than control (with placebo) group. When learnt before drug taken, recall better than placebo. Drug improved (facilitated) recall of material learnt beforehand.Wixted (2004)- suggests that drug prevents new info reaching parts of brain involved in processing memories- can't interfere retroactively. Shows forgetting can be linked to interference- when we reduce interference, we reduce forgetting.
86
What are the limitations of research into inteference
- poor mundane realism
- lacks ecological validity- artifical materials, unrealsitic procedures.
- crafted to have optimal conditions for interferrence- similar words- not often in everyday life- e.g. revising similar subjects, but not often
- Interference is temporary and can be overcome by using cues- Tulving and Psotka- list of words organised into 2 categories, one list at a time without knowing category. Recall around 70% for first list but got progressively worse after each list- interference. However, once told category, recall rose again to around 70%- starting point. Always in LTM? interference jus causes temporary loss- theory not predicted by interference theory
- Baddeley (1990) tasks given too close to eachother- only a few mins apart in studies but could be days-years in real life- e.g. learning language could be years apart.
87
What type of failure does an absence of cues cause
retrieval- the info os stored in LTM but can't be accessed
88
What is the theory related the forgetting due to retrieval failure/lack of cues
Encoding specificity principe
89
Describe the encoding specificity principe
- Tulving (1983)
- If cues are to be helpful they must be both present at encoding (when we learn material), and at retrieval
- follows from this that if cues available at encodig/retrieval are different/ not present, there will be some forgetting
90
Describe different types of cues
-encoded at time of learning in meaningful way- e.g. mnemonic techniques
- encoded in a non-meaningful way:
Context-dependent forgetting- recall depends on external cue (e.g. weather/place)
State-dependent forgetting- recall depends on internal cue (e.g. being upset or drunk)
91
Name research into retrieval failure
- Godden and Baddeley (1975)
- Goodwin et al (1969)
- Overton (1964)
92
Describe Godden and Baddeley's study (1975)
- investigated the effect of environment on recall
- 18 divers from Scottish diving club asked to learn 36 unrelated words of 2 or 3 sylabbles in 4 conditions (learn + recall on beach; learn + recall underwater; learn beach recall underwater; learn underwater recall beach)
- Found recall in different setting as 40% lower than same- 13.5 both on beach vs 8.5 beach then water
93
Describe Goodwins research (1969)
- 48 male medical students
- day 1 training, day 2 testing
4 groups:
1) SS- sober both days
2) AA- intoxicated both days
3) AS- intoxicated day one, sober day 2
4) SA- sober day 1, intoxicated day 2
- Intoxicated groups had 111mg/100 ml alcohol in blood- all showed signs of intoxication
- PPs had to perform 4 tests- avoidance task, verbal rote-learning task, word-association test, picture recognition task
- most errors made on day 2 in AS and SA condition than in AA or SS- however not case for recognition tes. SS best in all.
- conclusion- performance better when in same physiological state when learning and recall happens.
94
Describe Overtons (1964) research
- 2 groups of rats- one given mild barbiturate (form of sedative that can lead to drowsiness), other didn't get drug
- Placed in simple maze- taught to escape electrical shock
- when rats in group with drug placed back in cage without it, couldn't remember how to escape, but could when given drug again
95
What are strengths of research into retrieval failure
- Goodwin- good ecological validity as in everyday setting- findings not influenced by environmental factors. Also good control of variables- blood alcohol levels measured precisely-same level of intoxication for all. Also gained consent- ethically sound.
- Overton- animal studies- don't show demand characteristics, allows insight in situations otherwise unethical in humans, different set of legalities for experiments. Also supports Goodwin's findings.
- Real-world application- Baddeley- cues may not have strong effect but still worth paying attention to- e.g. going to room, forgetting why you came, go back and remember- shows us to return to original environment when forgotten something- can help us to improve recall in life.
- Resarch support- Carter and Cassady (1998)- gave antihistamine drugs-recall worse when mismatch of physiological conditions. Eysenck and Keane (2010) - retrieval failure main reason for forgetting from LTM- happens in real life as well as in labs.
96
What are weaknesses of research into retrieval failure
- lacks ecological validity and mundane realism- random words- not similar to material from every day life
- Goodwin- Demand characteristics- medical students- intelligent and likely led previous studies- may have been demand characteristics- decreases validity
- Overton- animal studies- hard to generalise to humans, ethically sound to shock rats?
- Baddeley (1997)- context effects not actually very strong- especially in every day life. Unlikely to be as different as land vs underwater- rooms less extreme forgetting as not different enough. Studies about lack of contextual cues may not explain much every day forgetting.
- recall vs recognition- studies may depend substantially on type of material being tested. Godden and Baddeley replicated study in 1980- using recognition instead of recall- Pp had to say whether they recognised word from list instead of retrieving themselves. Found no context-dependent effect- performance same in all 4 conditions. Suggests retrieval failure is limited explanation for forgetting as it only applies when a person has to recall info rather than recognise it.
- problems with ESP- lot of evidence that forgetting takes place when mismatch/absence of retrieval cues ( tulvings encoding specificity principle). However, is it possible to independently establish whether a cue has been encoded or not? Reasoning is circular- based on assumptions. In an experiment, if a cue didn't produce recall we assume it cant have been encoded, if it dod we assume it must have been- based off assumptions.
97
Define eyewitness testimony (EWT)
The ability of people tp remember the details of events such as accidents and crimes, which they themselves have observed- accuracy can be affected by variety of factors- anxiety, post-event discussion, misleading questions
98
Describe how anxiety can affect EWT
- crime- likely high levels during encoding stage of memory process- can affect accuracy- different in situations e.g. violent vs low level traffic offences
99
What is the law surrounding anxiety levels and performance, describe it
The Yerkes-Dodson law:
- Arousal low = low performance
- performance gets better as increases
- if too much, it becomes stress experienced as anxiety- performance begins to drop off, memory can be affected
- inverted U theory
100
Name 2 studies into the role of anxiety in EWT
- Loftus (1979)- weapon focus
| - Yuille and Cutshall (1986)- Canadian bank robbery
101
describe the aim and procedure of Loftus' 1979 experiment
Aim- to investigate the role of anxiety on EWT
Procedure-
- Pp exposed to 1 of 2 situations:
1- overheard low key conversation in a lab about equipment failure- person then emerged from lab holding pen with grease on his hands
2- overheard hostile and heated exchange between 2 people in lab. Sound of breaking glass and charshing chairs. Man emerged from lab holding paper knife covered in blood.
Pp given 50 photos of and asked to identify person who came out of lab
102
describe the findings and conclusions of Loftus' 1979 experiment
- pen- accurately identified person 49% of time
- knife- 33%
- weapon focus- witnesses focussed on the weapon due to survival instic- stopped them from recognising face
103
describe the strengths of Loftus' 1979 experiment
Supportive research:
- Loftus and Burns (1982)- Pp watched either violent or nonviolent short film of crime
- those who saw violent version in which boy was shot in the face were less accurate in recalling info about crime- supports YD U law
Lab experiment:
- high control of extraneous variables
- changes in dependent must be due to changes in independent variable- cause and effects established
- any differences in accuracy of recall due to change in scenario not other variables
104
describe the weaknesses of Loftus' 1979 experiment
Ethics:
- ethically unsound as Pp were deceived and may have been upset by witnessing bloody knife- breaks guideline of minimising pain and stress
- issue as psychologists have duty of care to protect Pps from harm
Ecological validity:
- not like real life- aware in experiment- not same response to knife- memory may be better/worse in real life
- supported by Yuille and Cutshall- real life contradictory
Other factors:
- could be knife was unusual not causing anxiety
- Pickel- hairderessrs- scissors, handgun, wallet or raw chicken- accuracy significantly lower in unusual- weapon focus may be due to abnormality not anxiety
105
Describe the procedure of Yuille and Cutshalls experiment (1986)
- study of actual shooting in shop in Vancouver, Canada
- Shop owner shot thief dead
- interviews 4-5 months after- compared to original police ones straight after
- accuracy determined by number of details
- also asked how stresses ( 7 point scale), and whether emotional problems since event
106
Describe the finding and conclusions of Yuille and Cutshalls experiment (1986)
- witnesses- very accurate- little change after 5 months
- Highest levels of anxiety- most accurate (88% vs 75%)
- anxiety doesn't have a detrimental effect on EWT in real life- may even enhance it
107
Describe the strengths of Yuille and Cutshalls experiment (1986)
Supporting evidence:
- Christianson and Hubinette
- 58 witnesses of actual bank robberies in Sweeden
- some directly involved eg workers, some not
- assumed closest involved had highest anxiety
- recall average was 75%- even higher when directly involved
- supports idea that anxiety may enhance
BUT- interviewed several months after event- 4-15 months- no control of what happened in intervening time- could have had other factors like post-event discussions- confounding variables
Ecological validity:
- real life shooting
- shows in real life, EWT can be accurate
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Describe the weaknesses of Yuille and Cutshalls experiment (1986)
Generalisability:
- Canada- hard to generalise to those not in Canada- just because Canadians responded in one ay doesn't mean others will
Natural experiment:
- little control over variables as real and natural
- hard to determine what determines the dependent variable. Could be several other extraneous variables that influenced result e.g. if witness was policeman, may have better recall of details due to professional training
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Who investigated the effect of leading questions on EWT
Loftus and palmer (1974)
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Describe the procedure of the first loftus and palmer experiment
- lab experiment
- aim to assess influence of leading questions on recall
- independent groups design
- IV- verb, 5 conditions
- DV- speed in mph
- 45 student Pp shown short video clip
- 5 groups
- All asked 'how fast were cars going when they ___ each other'
- each group was given different verb to fill gap- smashed, collided, bumped, hit or contacted
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Describe the results/conclusions of the first loftus and palmer experiment
- faster speed estimated with more severe verb- e.g. smashed was 41mph but contacted was 32mph
- estimate speed was affected by verb used- accuracy of EWT influenced by leading questions
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Describe the procedure of the second loftus and palmer experiment
- aim to investigate whether leading questions affect EWT's
- IV- verb, DV- whether saw broken glass
- 150 student Pps
- shown short film of multi veichle car accident, asked questions about it
- split into 3 groups
- 1 group asked speed when hit, one asked smashed, one group not asked
- asked to return 1 week later and asked if saw broken glass
- no broken glass in film
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Describe the results/conclusions of the second loftus and palmer experiment
- 16/50 saw glass when smash, 7 when hit, 6 control
| - having stronger verb led to higher percentage f seeing glass (inaccurate testimony)
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What are the strengths of Loftus and Palmers research
- lab study- no extraneous variables- good control of IV/DV
- real-world application- teaches legal system validity of EWT and factors that may have affected it- reduces amount of leading questions asked when gathering EWT's
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What are the weaknesses of Loftus and Palmers study
- lack of ecological validity- lab not rea life- hard to extrapolate to in-person witnessing- lower anxieties on video Foster et al (1994)- experiment recall doesn't matter in same way as real life recall
Limited sample- 45 students- lacks population validity- hard to generalise
- poor mundane realism- EWT isn't usually watching video and guessing speed
- Counter evidence:
- Yuille and Cutshall- sound EWT not influenced by leading questions (post 4 months interview, interview had to leading questions)- real life, higher stakes (would want to get shooter to prison etc)
Counter ti substitution explanation (that smash vs hi changed seeing broken glass):
- Sutherland and Hayne- when asked misleading questions abut video clip, recall was better of central details than peripheral nes- focused on central so resistant to misleading info- central not distorted- outcome not predicted by substitution explanation
- Demand characteristics- Zaragosa and McCloseky (1989)- many answers given in lab studies due to DC's- Pp wants to be helpful/ doesn't want to let researcher down so says what they think the researcher wants to hear/guesses when don't know the answer
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Name 2 studies on the effect of post even discussion on EWT (PED)
- Gabbert et al (2003)
| - wright et all (2000)
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Describe Gabbert et al's study
- 2 groups of Pps watched same crime from different angles- different details
- Pps led to believe they has watched same video
- Pps asked to recall event either alone or in pairs
- individual recall test then administered to examine effects of co-witness discussion on subsequent memory reports
- 71 % of witnesses who had discussed event report atleased 1 out of 2 wrong details acquired during discussion with co-wittness
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Describe Wright et al's study
- showed pairs of Pps identical crim, except half saw accomplice with thief and half didn't
- initial memories very accurate, but after discussing crime with other person in pair who saw slightly different sequence, 75% exhibited conformity
119
What are 2 reasons for the effect of PED on EWT
- memory contamination- when co-witnesses discuss a crime, EWT may be altered or distorted as they combined (mis)information from other witnesses with own memory
- memory conformity- Gabbert et al- witnesses often go along with each other, either to win social approval or because they believe the ither is witnesses were right and tey were wrong- but actual memory unchanged
120
What are strengths of the research into the effects of PED on EWT
- Practical application- tells police to not let witnesses discuss the events as may have memory conformation or contammination
121
What are weaknesses into the effects of PED on EWT
- wright- reported different details when alone- contamination not conformity
- Yuille and Cutshall- in real life but PED study wasn't- in Y/C, the recall was still accurate after months- could have discussed
122
WHat is an example of and interview method developed by psychologists to improve the accuracy of EWT
The cognitive interview- Gieselman et al (1985)
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What are the 4 principles of the cognitive interview
- Report everything- witnesses encouraged to recall every single detail about the event, even if some feel irrelevant or the witness doesn't feel confident about it- small details may be important and can trigger other important memories
- context reinstatement- witness should return to the original crime scene 'in their mind'- imagine the environment (weather, what they could see etc) and their emotions- gives context-dependent cues
- recall in reverse order events should be recalled in a different order to the original sequence- e.g. from final point back to beginning, or from middle to start. Done to prevent people from reporting their expectations of how the event must have happened rather than the actual event. Also prevents dishonesty- harder to produce untruthful event if reversed
- recall from changed perspective- should recall from other perspectives e.g. other witnesses or perpetrators. Done to disrupt effect of expectations and effect of schema on recall. The schema you have of a certain setting generates expectations of what should happen.
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what is the development of the cognitive interview
- The enhanced cognitive interview- fisher et al (1987)
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Describ eteh enhanced cognitive interview
- minimising distractions
- asking witness to speak slowly
- adapting language used to suit individual witness
- reducing anxiety
- avoiding judgemental and personal comments
- specific times of eye contact/removing it
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Who investigated the effectiveness of the cognitive interview schedule
Geisleman (1985)
127
What was the aim of Geislemans CI investigation
To test the effectiveness of the cognitive interview schedule by comparing it to standard police interviewing techniques
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What was the method of Geislemans CI investigation
- showed police training videos of violent crimes to group of 51Pps recruited through advertisement in local paper
- approximately 48 hours later, Pps interviewed individually by police officers using either standard or cognitive interview technique
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What were the results of Geislemans CI investigation
- more correct items were used when CI was used- 42 vs 36
- same amount of incorrect items- 9 in both
- same confabulated- 2 in both
130
Evaluate the research method used in Geislemans CI investigation
- independent groups
- les risk of demand characteristics as noting to compare to/work out prpouse
- However Pp variables not controlled
- lacks ecological validity- video- different levels of anxiety
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What are strengths of te cognitive inetrview
- Fisher et al- evidence to support effectiveness- trained group of detectives in Florida, assessed performance when interviewing real weaknesses- when compared to pre-training, information gain as much as 47% more- same effect using real witnesses
- Bekerian and Dennett- reviewed 27 such studies (meta analysis)- found in all cases, CI more accurate than other- consistently effective
- other meta analysis- Kohnken wt all- 55 studies- average 41% increase, only 4 no difference- HOWEVER, also found increase in inaccurate info especially in ECI- may sacrifice quality for quantity, police may use different versions- hard to compare
- Reduces miscarriages in justice in countries where these are likely to occur. Brazil- Stein and Memon- tested the effectiveness of CI compared to standard interrogation (which incl. torture)- found CI improved amount of correct info gained- may prove new way of interviewing in countries- reducing miscarriages of justice
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What are weaknesses of the cognitive interview
- Geiselman (1999)- CI has nothing to offer when identifying a suspect
- requires more time, effort, training and resources- when scarce resources, police may be forced to rely on standard interviews. Kebbell and Wagstaff- time-limited. not realistic
- Geiselman- children under 6 years old actually reported events slightly less accurately in response to CI techniques, possibly as found instructions hard to undrestand- children may be only witness so not generalisable
- Not all elements equally useful- Milne and Bull- each of 4 techniques alone produced more than SI but found combo of context reinstatement an report everything found better recall of any others or any other combo- confirmed police officers suspicion that some aspects of CI more useful than others- doubt on credibility of overall CI
