Memory Flashcards
What is coding?
The format in which information is stored in various memory stores
What is capacity?
The amount of information that can be held in a memory store at a given time
What is duration?
The length of time information can be held in a memory store
What is short term memory?
The limited capacity store. Coding is mainly acoustic, capacity is between 5 and 9 items, duration is between 18 and 30 seconds.
Capacity can be increased via chunking
What is long term memory?
The permanent memory store. Coding is mainly semantic, it has unlimited capacity and can store memories for up to a lifetime
Research into capacity, coding and duration of STM and LTM
Coding: Baddely (STM, LTM)
Capcity
STM - Jacobs and Miller
Duration:
STM - Peterson and Peterson
LTM - Bahrick
Baddeley aim
Research coding into stm and LTM
Baddeley procedure
- 4 sets of word lists - acoustically similar and dissimilar, semantically similar and dissimilar.
- participants recalled the order of word lists
- done immediately to assess stm and after 20 minutes for ltm
Baddeley findings
Participants given acoustically and Semantically similar words had the worst recall
They confused the similar sounding and meaning words
Baddeley conclusions
- lists that had poor recall showed that the words had become confused
- for immediate recall, acoustically sounding words weren’t remembered well, showing stm is acoustically coded as they remembered the others fine.
- for delayed recall, semantically sounding words were not remembered well, showing that LTM is semantically coded
Jacobs aim
Research capacity of stm
Jacobs procedure
Developed a technique to measure digit span - how many items an individual can remember, in sequence and repeat back in order
Jacobs findings and conclusions
Mean span for digits was 9.3 items and for letters it was 7.3
Concluded memory can hold 7-9 items
Miller aim
Research capacity of stm
Miller procedure
Observed things come in sevens e.g. days of the week.
Also used the digit span technique but ‘chunked’ items into groups e.g. sets of numbers
Miller findings
People could recall 5 words as well as they could recall 5 letters, via chunking
Miller conclusions
Used the term ‘the magical number seven’ to describe the capacity of stm
Peterson and Peterson aim
Research duration of stm
Peterson and Peterson procedure
- 24 students took part in 8 trials and were given a consonant syllable/trigram and asked to count backwards to prevent rehearsal
- on each trial, they were stopped after either 3,6,9,12,15 or 18 secs. This was the retention interval
Peterson and Peterson findings
STM lasts about 18 seconds after this, very few people correctly recall the consonant syllable
Peterson and Peterson conclusions
STM has a very short duration, unless it is rehearsed
Bahrick aim
Research duration of ltm
Bahrick procedure
Tested recall of people participants had gone to school with using photo recognition (50 yearbook photos) and free recall (recalled names)
Bahrick findings
90% accuracy for photo recognition for people who had graduated within 15 years ad 60% accuracy for free recall.
After 48 years photo recognition recall about 70% and 30% for free recall
Bahrick conclusions
LTM lasts a very long time
What are the features of the MSM
Sensory register - coding = iconic and echoic
capacity = high
Duration = less that 1/2 second
STM - coding = acoustic
Capacity = 5-9
Duration = 18-30 seconds
LTM - coding = semantic
Capacity =unlimited
Duration = unlimited
What is the multi-store model of memory?
A representation of how memory works in terms of three stores called sensory register, STM and LTM.
It describes how information is transferred from one store to another, how it is remembered and how it is forgotten
Sensory register
The memory store for each of the 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.
The capacity of the sensory register is huge and information lasts for a very short time - less than half a second
What does the msm describe
The flow between three permanent storage systems of memory
Developed by Atkinson and Shiffrin
What happens in the sensory register
Where information from the senses is stored, but only for a short duration before it is forgotten
It is modality-specific i.e. whichever sense is registered will match the way it is consequently held (a taste is held as a taste)
How can info from the sr move to the stm
If attended to, sensory information moves into the stm for temporary storage, which is primarily encoded acoustically (as a sound)
How do the stores work together to move info to the ltm
Rehearsing information via the rehearsal loop helps to retain the information in the stm, and consolidate it to the ltm, which is predominantly encoded semantically.
Information can be stored and retrieved for up to any duration, and equally has seemingly unlimited capacity
Primary recency effect
- tendency to remember the first and last items in a series better than those in the middle
- form of cognitive bias that is thought to be due to how information is processed and stored in memory
Murdock
- primary recency effect
- list of 10 to 40 words, one word at a time, one word per second
- asked to recall as many words as possible in any order
- words early in the list were put into ltm (primary effect) because they have had time to rehearse acoustically
- words from the end were put into stm (recency effect)
- words in the middle were forgotten
Glanzer and cunitz
- primary recency effect
- randomly assigned immediate or delayed recall
- both groups presented with a list of 12 monosyllabic words, one at a Tim, one per second
- immediate recall was asked to recall words immediately
- delayed recall were asked to count backwards in threes for 30 seconds before recalling the words
What can ltm be split up into
Declarative (explicit) and procedural (implicit)
Explicit - memories hat can be inspected and recalled consciously
Implicit - memories that are unable to be consciously recalled
Episodic memory
- 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
What is involved in episodic memory
- they are ‘time stamped’
- type of declarative memory
- prefrontal cortex is involved in initial coding with consolidation and storage involving the neocortex and hippocampus
Semantic memory
- a long term memory store of our knowledge of the world
- this includes facts and our knowledge of what words and concepts mean
- these memories usually need to be recalled deliberately
What is involved in semantic memory
- type of declarative memory
- the conscious recall is of facts that have meaning
- hippocampus, frontal lobes and temporal lobes are involved
Procedural memory
- a long term memory store of 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
What is involved in procedural memory
- procedural memory
- the neocortex including the primary motor cortex, cerebellum and prefrontal cortex are involved
Working memory model
A representation of stm that suggests that stm is a dynamic processor of different types of information using sub-units coordinated by a central decision-making system
Central executive
The component of WMM that coordinates the activities of the three subsystems in memory. It also allocates processing resources to those activities
Phonological loop
The component of WMM that processes information in terms of sound. This includes written and spoken material. It is divided into the phonological store and the articulatory process
Visio-spatial sketchpad
The component of WMM that processes visual and spatial information in a mental space often called the ‘inner eye’
Episodic buffer
The component of WMM that brings together material from the other subsystems into a single memory rather than separate strands. It is also bridge between working memory and ltm.
Features of each store in the WMM model
Central executive:
coding = all sensory forms
Capacity = one strand of info at a time
Phonological loop:
Coding = auditory
Capacity = amount of info spoken aloud in 2 seconds
Visio-spatial sketchpad:
Coding = visual and spatial
Capacity = 3 or 4 objects
Episodic buffer:
Coding = all sensory forms
Capacity = 4 chunks of info
Role of the working memory model
- aimed to overcome problems of msm
- Baddeley and hitch developed the WMM which focuses specifically on the workings of stm
- Atkinson and shiffrins msm was criticised for over-simplifying stm and ltm as a single memory store, so the WMM alternatively proposed that stm is composed of three, limited capacity stores
Role of central executive
- manages attention
- Controls information in all sensory forms but is only able to deal with one strand of info at a time
- limitation is that it simply describes it rather than being explanatory
Role of phonological loop
- temporarily retains language based info in auditory form and holds the amount of information that can be spoken out loud in two seconds
- consists of an articulatory rehearsal process and the phonological store:
- articulatory rehearsal process (inner voice) of language, allows maintenance rehearsal. This includes any language presented visually that is then converted to a phonological state. It involves sub vocal repetition
- the phonological store (inner ear) which holds auditory speech info and the order in which it was heard
Role of Visio-spatial sketchpad
- temporarily retains visual and spatial info (colour, form, space/distance)
- can hold 3 or 4 objects at one time
- consists of the visual cache which stores visual information about form and colour: the inner scribe which deals with spatial relationships and the arrangement of objects
Role of episodic buffer
- a later addition which facilitates communication between the components of the WMM and ltm
- it integrates info from the other stores and maintains a sense of time sequencing
- can hold 4 chunks of info
Difference between episodic buffer and central executive
Central executive is the sorter. Info arrives after the ce has paid attention. It then controls where the info goes - pl or Vss
(Doesn’t process info but separates it)
Episodic buffer is the link between the ce and ltm. Before it was introduced there was no way info from the ltm could enter the WMM. The eb also holds information together and remembers the sequence
(Brings it all together - finished product)
Interference theory
- forgetting because one memory blocks another, causing one or both memories to be distorted or forgotten
- explanation for forgetting in ltm. Once info reaches ltm, it i more or less permanent, therefore forgetting is thought to occur because we cannot access the information, even though it is thought to be available
- basic theory states that interference occurs when information that is similar in format gets in the way of the info that someone is trying to recall
Proactive interference
Forgetting occurs when older memories that are already stores disrupt the recall of newer memories
The degree of forgetting is greater when the memories are similar
Retroactive interference
Forgetting occurs when newer memories disrupt the recall of older memories that are already stored
The degree of forgetting is greater when memories are similar
Effects of similarity - aim
McGeoch and McDonald investigated retroactive interference
Effects of similarity - procedure
Participants had to learn a list of 10 words until they could remember them with 100% accuracy. They then had to learn another list of words. There were 6 different conditions, each with a different second word list to remember
1 - synonyms
2 - antonyms
3 - unrelated words
4 - none sense syllables
5 - 3 digit numbers
6 - no new list
Effects of similarity - findings
Recall of the original list was dependent on the nature of the second list
The most similar material, group 1 synonyms, produced the worst recall
Effects of similarity - conclusions
This shows that interference is strongest when the memories are similar
What is the retrieval failure theory?
A form of forgetting.
It occurs when we do not have the necessary use to access memory.
The memory is available but not accessible unless a suitable cue is provided
What is a cue?
A ‘trigger’ of information. Such cues may e meaningful or may be indirectly linked by being encoded at the time of learning. They can be external (environmental context) or internal (mood or state)
The encoding specificity principle
Recall of information is best when there is a large overlap between the information available at the time of retrieval (cues) and the info in the memory trace (from learning)
Context-dependent forgetting
A form of forgetting where recall occurs in a different external setting to coding
State-dependent forgetting
A form of forgetting where recall occurs in a different internal setting to coding
How do context and sate dependent forgetting work together
When info is initially placed in a memory, associated cues are stored at the same time. The suggestion is that internal ad external cues can help facilitate recall of a LTM.
If these cues are not available at the time of recall, it may make it appear as though info has been forgotten i.e context and state dependent forgetting
How can the chances of recalling the memory be increased?
If the context and state of the individual are similar at recall to the situation where the memory was originally placed
Godden and Baddeley’s aim
To investigate context dependent forgetting
Godden and Baddeley’s procedure
Divers learnt. Last of words either underwater or on land and were then asked to recall the words either underwater or on land
1
Learning - land
Recall - land
2
Learning - land
Recall - underwater
3
Learning - underwater
Recall - land
4
Learning - underwater
Recall - underwater
Godden and Baddeley’s findings
N conditions 1 and 4, where learning and recall conditions matched, recall was 40% higher than in non-matching conditions
Godden and Baddeley’s conclusions
External cues available at learning help to trigger memories if they are also there at recall
Carter and cassaday’s aim
To investigate state-dependent forgetting
Carter ad cassaday’s procedure
Antihistamine drugs were given to their participants, making them feel drowsy. They had to earn a list of words and passages of prose and then recall the information, when they were wither under the influence of the drugs or in a ‘normal state’.
1
Learning - on drug
Recall - on drug
2
Learning - on drug
Recall - not on drug
3
Learning - not on drug
Recall - on drug
4
Learning - not on drug
Recall - not on drug
Carter and cassaday’s findings
In conditions where there was a mismatch between internal state at learning and recall, performance on the memory test was significantly worse
Carter and cassaday’s conclusions
Internal cues available at learning help to trigger memories i they are also there at recall
What is an eyewitness testimony
The evidence given in court or a police investigation, by someone who as witnessed a crime or accident
What is a misleading information
Incorrect information given to an eyewitness following an event. It gives them the wrong impression. This can be during post-event discussion or take the form of leading questions
What is a leading question
A question which, because of the way it is phrased, suggests a certain answer
Decreases accuracy
What is post-event discussion
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.
Repeat interviewing also creates a form of this. It may influence the accuracy of each witness’ recall of the event
What were the 2 experiments loftus and palmer conducted to investigate leading questions
Experiment 1 - investigating the effect of leading questions on EWT
Experiment 2 - investigating the effects of leading questions on later memory
Experiment 1 procedure
- 45 American students - 5 groups of 9
- all participants watched a video of a car crash, answered a questionnaire and were asked specific questions about the speed of the car
- loftus and palmer manipulated the verb used in the question e.g. “ how fast were the cars going when they___ with each other?”
Simon - smashed
Cowell - collided
Bit - bumped
His - hit
Cat - contacted
Experiment 1 findings
They found that the estimated speed was affected by the very used
Smashed - 40.8mph
Contacted - 31.8mph
Experiment 1 conclusions
The results clearly show that the accuracy of EWT is affected by leading questions and that a single word in a question can significantly affect the accuracy of our judgements
Experiment 2 procedure
- 150 students - 3 groups of 50
- all students watched a one-minute video depicting a car accident and were then given a questionnaire to complete
- one group was asked “how fast were the cars going when they smashed into each other?” One was asked “hit” and the control group was not asked about the speed of the vehicles
- one week later the participants returned and were asked a series of questions about the accident. The critical question was “did you see any broken glass?” There was no broken glass
Experiment 2 findings
The verb smashed has connotations of faster speeds and broken glass and this question led the participants to report seeing something that was not actually present
Smashed - 16 said broken glass
Hit - 7 said broken glass
Control - 6 said broken glass
Experiment 2 conclusions
Their memory for the original event was distorted by the question used one week earlier, demonstrating the power of leading questions
How can leading questions impact EWT?
Response bias - the wording of the question has no real impact on the memories, it just influences how they decide to answer. When participants get a leading question like ‘smashed’ it encourages them to choose a higher speed estimate
Substitution explanation - the wording of a Question can actually change the memory. This was demonstrated in loftus’ second experiment, where the participants had their memory altered depending on which word they heard in the original question
Gabert et al’s aim
Investigated the effect of post-event discussion on the accuracy of EWT
Gabert et al’s procedure
- 60 students and 60 older adults recruited from a local community. They watched a video of a girl stealing money from a wallet, but it had been filmed from different points
- participants were either tested individually (control) in pairs (co-witness) on their recall
- participants in the co-witness group were told that they had watched the same video, but they had seen different perspectives of the same crime and only one person has actually witnessed the girl stealing. They discussed the crime together
- all participants then completed a questionnaire, testing their memory of the event
Gabert et al’s findings
71% of the witnesses in the co-witness group recalled information they had not actually seen
The control group did not recall any information that they had not seen
Gabert et al’s conclusions
These results highlight the issue of post-event discussion and the powerful effect this can have on the accuracy of EWT
What is anxiety
A state of emotional and physical arousal
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 can affect the accuracy and detail of EWT
Thought to have a positive and negative effect on the accuracy of EWT
How does anxiety have a negative impact on recall?
Loftus proposed the ‘weapon focus effect’, which suggests that the anxiety caused as a result of witnessing a weapon focuses the attention away from the potential perpetrators and reduces the accuracy of EWT
Johnson and Scott’s procedure
Invited participants to a lab, where they were told to wait in the reception area. A receptionist went to run an errand, leaving the participant alone
Independent groups design, as participants were then exposed to one of two conditions
Lab experiment
Both groups were shown 50 photos and asked to identify the person who had left the lab
The participants were informed that the suspect may or may not be present in the photos
What were the conditions in Johnson and Scott’s experiment
-‘no weapon condition’ - participants overheard an argument in the lab. An individual (the target) left the lab and walked past the participant with their hands covered in grease holding a pen
-‘weapon condition’ - participants overdone same argument and the sound of breaking glass. This was followed by an individual (target) walking into the reception area, holding a bloodied letter opener
Johnson and Scott’s findings
Those who had witnessed he man holding the pen correctly identified the target 49% o the time compared to those who had witnessed the man holding a knife who correctly identified the target 33% of the time
Johnson and Scott’s conclusions
Loftus claimed that the participants who were exposed to the knife has higher levels of anxiety and were more likely to focus their attention on the weapon and not the face of the target, a phenomenon known as the weapon focus effect.
Therefore, the anxiety associated with seeing a knife reduces the accuracy of EWT
Yuille and cutshall’s procedure
Conducted a study into a real-life shooting. The shop owner shot a thief dead. There were 21 witnesses, 13 agreed to take part
Field study
Interviews happened 4-5 months after the incident and were compared to the original EWT interviews to the police at the time of the shooting.
Accuracy was determined by the number of details reported in each account.
The witnesses also rated their stress levels at the time of the incident on a 7 point scale and asked if they had any emotional problems since the event
Yuille and cutshall’s findings
The witnesses were very accurate in their accounts and there was little change in the amount of accuracy after 5 months
Those who reported the highest levels of stress were most accurate. About 88% compared to 75% for the less stressed group
Yuille and cutshall’s conclusions
Anxiety can improve the accuracy of EWT
What is the inverted u hypothesis
-deffenbacher applied yerkes and Dodsons hypothesis to explain the contradictions
- this suggests that the relationship between accuracy and anxiety looks like an inverted u. Lower levels of anxiety reduced lower levels of recall accuracy. Memory becomes more accurate as the level of anxiety experienced increases
- however, there comes a point where the optima level of anxiety is reached. This is the point of maximum accuracy. If an eyewitness experiences any more stress than this, their recall of the event suffers a drastic decline i.e. the recall accuracy decreases
The standard police interview
Geiselman and colleagues identified several ways that standard police interview methodology could negatively Maputo eyewitnesses recall accuracy of crimes:
-regular jumps between memory modalities
-event recall in a non-chronological order
-false memories due to leading questions
The cognitive interview
Geiselman et al integrated effective memory recall techniques into a new questioning methodology - the CI to achieve more detailed and accurate EWT
At the start of the interview, the interviewer attempts to help the witness feel relaxed and seeks to tailor their language to suit the individual. The interviewer aims to be non-judgemental and avoids personal comments throughout.
There are 4 techniques;
-report everything
-reinstate the context
-reverse the order
-change perspective
Report everything
Witnesses are encouraged to include ever single detail of the event, even though it may seem irrelevant or the witness isn’t confident about it
Why report everything?
Seemingly trivial details ma be important ad may trigger other important memories
Reinstate the context
Witnesses should return to the original crime scene in their minds and imagine the environment and their emotions
Why reinstate the context?
Related to context/state dependent forgetting. Reinstating physical and mental context may act as a cue or trigger to recall
Reverse the order
Events should be recalled in a different chronological order to the original sequence
Why reverse the order?
To prevent people reporting their expectations of how the event must have happened rather than the actual events
Prevents dishonesty as it is more difficult to produce an untruthful account in reverse order
Change perspective
Witnesses should recall the incident from other people’s perspectives e.g. how it appeared to other witnesses/perpetrator
Why change perspective?
To disrupt the effect of expectations and scheme on recall. It promotes a more ‘holistic’ view of the event which may enhance recall
What does the CI focus on?
Utilising retrieval cues, as geiselman et al claimed that recalling details of an event in a variety of different contexts is key to ‘cueing’ retrieval of a large amount of accurate info from memory - which the standard police interview was restrictive in ding
The enhanced cognitive interview
Fischer et al developed some additional elements to the CI to focus on the social dynamics of interactions e.g. the interviewer needs to know when to establish eye contact and when to relinquish it
The ECI also includes ideas such as reducing eyewitness anxiety, minimising distractions, getting the witness to speak slowly and asking open-ended questions
