MEMORY Flashcards
Define Capacity
A measure of how much can be held in memory. It is represented in terms of bits of information such as number of digits
Define Coding
The way information is changed so that it can be stored in memory. Information enters the brain via the senses (e.g. eyes and ears). It is then stored in various forms, such as visual codes (like a picture), acoustic codes (sounds) or semantic codes (the meaning of the experience)
Define Duration
A measure of how long a memory lasts before it is no longer available
Define Long-term memory (LTM)
Your memory for events that have happened in the past. This lasts anywhere from 2 minutes to 100 years. LTM has potentially unlimited duration and capacity and tends to be coded semantically
Define Short-term memory (STM)
Your memory for immediate events. STMs are measured in seconds and minutes rather than hours and days i.e. a short duration. They disappear unless they are rehearsed. STM also has a limited capacity of about four items or chunks and tends to be coded acoustically. This type of memory is sometimes referred to as working memory
Describe research that has investigated capacity in STM
- Jacobs (1887) used digit span to assess capacity (consisted of multiple columns and as you progressed there were more digits and letters than the last that you had to say, the close your eyes and remember)
- Found that the average space for digits was 9.3 items and 7.3 for letters
- Jacobs theorised it may have been easier to memories digits since there are only 9 digits but 26 letters
- Miller (1956) reviewed psychological research and concluded that the span of immediate memory is about 7 items - sometimes a bit more, sometimes a bit less
- In an article called ‘The magic number seven plus or minus two’
- If there were 12 dots on a screen and then they were covered, people could only recall 7 - same for musical notes, letters and words
Describe research that has investigated duration in STM
- Peterson and Peterson (1956) studied the duration of STM using 24 students - each tested over 8 trials
- A participant was given a consonant syllable and a three-digit number (e.g. THX 512)
- Participants had to recall the consonant syllable after a retention interval on 3, 6, 9, 12, 15 or 18 seconds
- During the retention interval, they had to count backwards from their three-digit number
- Found 90% correct over 3 seconds, 20% correct after 9 seconds and 2% after 18
Describe research that has investigated duration in LTM
- Bahrick et al. (1975) tested 400 people aged 17-74 on their memory of classmates by doing a photo recognition test with 50 photos from their yearbooks
- Also a free-recall test where participants had to list names they could remember of those in their graduating class
- Participants who were tested within 15 years of graduation were 90% accurate
- Participants tested after 48 years, 70%
- Free recall: 15 years = 60%, 48 years = 30%
Describe research that has investigated coding in STM and LTM
- Baddeley (1966a and 1966b) tested acoustically and semantically similar words
- Participants had difficulty remembering acoustically similar words in STM but not LTM
- But semantically similar words posed little problem for STMs but led to muddled LTMs
- Suggests STM is encoded acoustically and LTM is encoded semantically
What is the multi-store model of memory?
An explanation of memory based on three separate memory stores, and how information is transferred between these stores
What is the sensory register?
Information at the senses - collected by eyes, ears, nose, fingers, and so on
Retained for a very brief period by the sensory registers (we can only hold accurate images of sensory information momentarily - less than 1/2 a second)
Large capacity
Encoding method depends on the sense
Outline the multi-store model of memory
- Atkinson and Shiffrin (1968) suggested in MSM as a theoretical model of memory. It is unitary
- Consists of three memory stores
- The first store in gaining and retaining information is the sensory register, where information is held at the senses (eyes, ears, nose, fingers, tongue, etc..) | Large capacity but very short duration
- To move onto the next store (STM), you must pay attention to sensory information at the sensory register
- Information is retained in STM via maintenance rehearsal and moves onto LTM via elaborative rehearsal
- Information can be retrieved from LTM via retrieval
- Information can be lost from any of the memory stores at any time
What is the Working Memory Model?
A model of memory proposed by Baddeley and Hitch (1974) used when working on a task. Each store is qualitatively different
What are the components on the Working Memory Model?
Central Executive
Episodic Buffer
Visuo-spatial Sketchpad
Phonological Loop
Long-term Memory
What is the central executive?
Monitors and coordinates all other mental functions in working memory. Essentially - the equivalent of paying attention to
What is the episodic buffer?
Added by Baddeley in 2000 due to the realisation that the model needed a general store
Receives input from many sources, temporarily stores this information, and then integrates it in order to construct a mental episode of what is ben experienced
What is the phonological loop?
One of two slave systems in the WMM. Codes speech sounds in working memory, typically involving maintenance rehearsal (repeating the words over and over again). This is why this component of working memory is referred to as a ‘loop’.
Contains the Phonological store (inner ear) and the Articulatory process (inner voice)
What is the visuo-spatial sketchpad?
Codes visual information in terms of separate object as well as the arrangement of these objects in one’s visual field
Contains the Visual cache and Inner scribe
What is a visual cache?
Stores information about visual items (e.g. form and colour)
What is an inner scribe?
Stores the arrangement of objects in the visual field
What is the phonological store?
Holds the words you hear (inner ear)
What is an articulatory process?
Used for words that are heard or seen. These words are silently repeated/looped (inner voice)
Maintenance rehearsal
Describe one research study that supports the WMM
- Shallice and Warrington (1970) studied KF
- KF’s short-term forgetting of auditory information was much greater than that of visual stimuli
- His auditory problems were limited to verbal material such as letters and digits but not meaningful sounds
- Brain damage restricted to Phonological Loop
- Supports the idea of separate visual and spatial systems, as suggested by the WMM
What is episodic memory?
Personal memories of events
e.g. what one did yesterday or a teacher one liked
This kind of memory includes contextual details plus emotional tone
What is procedural memory?
Memory of how to do things
e.g. riding a bike or learning how to read
Such memories are automatic as the result of repeated practice
What is semantic memory?
Shared memories for fact and knowledge
e.g. concrete things like knowing that ice is made of water OR abstract things like mathematical knowledge
What is interference?
An explanation for forgetting in terms of one memory disrupting the ability to recall another. This is most likely to occur when the two memories have some similarity.
There are two types: retroactive and proactive
What is Retroactive Interference (RI)?
New learning/information interfering with old learning/information
e.g. forgetting your old phone number as you now have a new one
What is Proactive Interference?
Old learning/information interfering with new learning/information
e.g. struggling to learn new phone number as you keep recalling your old phone number
Describe one study that demonstrated that interference may cause forgetting
- Baddeley and Hitch (1977) investigated interference effects in an everyday setting of rugby players recalling the names of the teams they had played against over a rugby season
- Some players played in all games but some missed a few games due to injury
- Time from start to end of season was the same for all players but number of games played differed
- If decay theory is correct, all players should recall a similar percentage of the games played because time alone should cause forgetting
- If interference theory is correct, then those players who played most games should forget proportionately more due to interference (BADDELEY AND HITCH FOUND THIS)
What is context-dependent forgetting?
When external cues at the time of learning do not match those present at the time of recall
What is state-dependent forgetting?
When our internal cues at the time of learning do not match those at the time of recall
Describe one study that demonstrated context-dependent forgetting
- Godden and Baddeley (1975) investigated learning and recalling information on land and underwater
- Comprised of 18 participants (13 male and 5 female) part of a university diving club, and were divided into four conditions
- Conditions: Learning words on land/recalling words on land, learning words on land/recalling words underwater, learning words underwater/recalling words underwater, learning words underwater/recalling words on land
- REPEATED MEASURES DESIGN
- RESULTS: words learned on land were better recalled on land + words learned underwater were better recalled underwater
Describe one study that demonstrated state-dependent forgetting
- Goodwin et al. (1975) carried out an experiment on emotional state 48 male medical students to recall words when either drunk or sober
- Participants were asked to recall after 24 hours, when some were sober but had to get drunk again
- Conditions: Sober on both days (SS), drunk on both days (AA), sober on day 1/drunk on day 2 (SA), drunk on day 1/sober on day 2 (AS)
- RESULTS: more errors made on day two in AS or SA state than AA or SS state | SS participants performed best
What are ‘cues’
Triggers of information recollection
What is Tulving’s ‘Specificity Encoding Principle’?
Retrieval failure suggests that forgetting occurs when the ‘cues’ present at the time of encoding the information are not present at the time of recalling the information
What is Eyewitness Testimony?
The evidence provided in court by a person who witnessed a crime, with a view to identifying the perpetrator of the crime
What is a leading question?
A question that, either by its form or content,suggests to the witness what answer is desired or leads them to the desired answer
What is misleading information?
Supplying information that may lead a witness/ memory of a crime to be altered
The two types are leading questions and post-event discussion
What is post-event discussion?
A conversation between co-witnesses or an interviewer and an eyewitness after a crime has taken place which may contaminate a witness’ memory for the event
Describe one research study related to the effect of misleading information on eyewitness testimony.
LEADING QUESTIONS
- Loftus and Palmer (1974) showed 45 students seven films of different traffic accidents
- After each film, the participants were given a questionnaire asking them to describe the accident and answer a series of specific questions about it.
- Critical question: ‘How fast were the cars going when they hit each other?’ One group got this question while the other four got the verbs ‘smashed’, ‘collided’, ‘bumped’ or ‘contacted’ instead of hit
- They found the mean speed estimate differed between the group depending on the verb used: smashed = 40.8 mph, collided = 39.3 mph, bumped = 38.1 mph, hit = 34 mph, contacted = 31.8 mph
- Loftus and Palmer (1974) then aimed to investigate if the leading question may bias a participant’s response or may actually cause information to be altered before it is stored
- A new set of participants was divided into three groups and shown a film of a car accident lasting 1 minute
- They answered a questionnaire about speed then returned 1 week later to answer more questions
- Critical question: ‘Did you see any broken glass?’ There was no broken glass but those who thought the car was travelling faster might think there would be broken glass
- They found that the leading question did change the actual memory about the event.
Describe one research study related to the effect of misleading information on eyewitness testimony.
POST-EVENT DISCUSSION
- Gabbert et al. (2003) investigated co-witnesses reaching a consensus view of what actually happened in an event
- Participants were in pairs where each partner watched a different video of the same event so that they each viewed unique items
- Pairs in one condition were encouraged to discuss the event before each partner individually recalled the event they watched
- 71% of witnesses who had discussed the event went on to mistakenly recall items acquired during the discussion
- THIS IS THE CONFORMITY EFFECT
OR
- LaRooy et al. (2005) investigated the contamination of an eyewitness’ memories based on multiple interviews and comments from the interview
- The interviewer may also use leading questions to alter the individual’s memory of events (children are highly susceptible)
What is anxiety?
An unpleasant emotional state that is often accompanied by increased heart rate and rapid breathing, i.e. physiological arousal
Explain how anxiety might affect the accuracy of eyewitness testimony
Stress (and anxiety) has a negative effect on memory as well as performance generally
Automatic skills are not affected by stress/physiological arousal but performance on complicated cognitive tasks is reduced by stress
Describe one research study related to the negative effect of anxiety on eyewitness testimony
- Johnson and Scott (1976) aimed to investigate the weapon focus effect and its affect on eyewitness testimony
- Participants were asked to sit in a waiting room where they heard an argument in an adjoining room. From here, they experienced one of two conditions: a man later ran out carrying a pen covered in grease (low anxiety condition) or a man later ran out carrying a knife covered in blood (high anxiety condition). participants were later asked to identify this man from a set of photographs
- The findings supported the weapon focus effect. Mean accuracy was 49% in identifying man from pen condition, and 33% accuracy in the knife condition
What is the weapon focus effect?
The view that a weapon in a criminals’ hand distracts attention (because of the anxiety it creates) from other features and therefore reduces the accuracy of identification
What is the Yerkes-Dodson effect?
The observation that arousal has a negative effect on performance (such as memory) when it is very low or very high.
Moderate levels of arousal are the most beneficial on performance
INVERTED U-SHAPED CURVE
Describe one research study related to the positive effect of anxiety on eyewitness testimony
- Christianson and Hubinette (1993) found evidence of enhanced recall when they questioned 58 real witnesses to bank robberies in Sweden
- The witnesses were either victims (bank teller) or bystanders (employee or customer) + questioned 4-15 months after the robberies
- All witnesses showed generally good memories for the details of the robberies (better than 75% recall)
- Witnesses who were the most anxious (bank tellers) had the best recall. ANXIETY DOES NOT REDUCE ACCURACY OF RECALL
- Christianson (1992) concluded that memory for negative emotional events is better than for neutral events (at least for central details)
Describe one research study related to the positive effect of anxiety on eyewitness testimony
- Christianson and Hubinette (1993) found evidence of enhanced recall when they questioned 58 real witnesses to bank robberies in Sweden
- The witnesses were either victims (bank teller) or bystanders (employee or customer) + questioned 4-15 months after the robberies
- All witnesses showed generally good memories for the details of the robberies (better than 75% recall)
- Witnesses who were the most anxious (bank tellers) had the best recall. ANXIETY DOES NOT REDUCE ACCURACY OF RECALL
- Christianson (1992) concluded that memory for negative emotional events is better than for neutral events (at least for central details)
What did Deffenbacher (1983) do?
- Reviewed 21 studies of the effects of anxiety on eyewitness memory
- Found that 10 of these studies had results that linked higher arousal levels to increases eyewitness accuracy while 11 showed the opposite
- Deffenbacher suggested the Yerkes-Dodson effect can account for this inconsistency
What is the cognitive interview?
A police technique for interviewing witnesses to a crime, which encourages them to recreate the original context of the crime in order to increase the accessibility of stored information
Who developed the cognitive interview?
Geiselman et al. (1984)
What techniques are used in the cognitive interview?
- Mental reinstatement of original context
- Report everything
- Change order
- Change perspective
Explain the ‘mental reinstatement of original context’ technique of the cognitive interview
The interviewer encourages the interviewee to mentally recreate both the physical and psychological environment of the original incident
The aim is to make memories accessible. People often cannot access memories that are there + need the appropriate contextual and emotional cues to do so
Explain the ‘report everything’ technique of the cognitive interview
The interviewer encourages the reporting of every single detail of the event without editing anything even though it may seem irrelevant. Witnesses should not leave anything out even if they believe it to be insignificant or irrelevant.
Memories are interconnected with one another so that recollection of one item may then cue a whole lot of other memories.
Explain the ‘change order’ technique of the cognitive interview
The interviewer may try alternative ways through the timeline of the incident, e.g. by reversing the order in which events occurred.
The rationale behind this is that our recollections are influenced by schemas. E.g. if you think about when you went to restaurant a few weeks ago your recollection will be influenced by your general expectations (schema) of what is likely to happen at a restaurant- you’re seated at a table, a server takes your order, etc. If you have to recall the events stating from the end of the event backwards this prevents your pre-existing schema influencing what you recall
Explain the ‘change perspective’ technique of the cognitive interview
The interviewee is asked to recall the incident from multiple perspectives, e.g. by imagining how it would have appeared to other witnesses present at the time
This is also don’t to disrupt the effect schemas have on recall
