Memory Flashcards
What is coding?
How information is stored in the various memory stores
What is capacity?
How much information that can be held in the memory store
What is duration?
The length of time information can be held in the memory
What are the research studies for capacity?
Digit span - Jacobs
Researcher read out a certain number of digits and the participant had to read them back in the same order (this was repeated until they couldn’t do it)
Mean digit span: 9.3
Mean letter span: 7.3
Span of memory/chunking - Miller
Notices that things came in 7’s and found that the capacity of the human memory is 7 items (+/- 2)
Chunking is grouping sets of digits/letters into units
What are the evaluations of capacity studies?
Digit span
+ has been replicated and a valid test of STM
- early study so may have lacked control and participants may have been distracted (confounding variable)
Span of memory/chunking
+ research led to further development about short term memory that is accurate today
- may have overestimated the capacity due to evidence from further research
What are the research studies for duration?
Short term - Peterson + Peterson
Participants had to recall a trigram (3 letters) after counting backwards in different multiples.
After 3 seconds retention was 80%
After 18 seconds retention was 3%
Long term - Bahrick et al
Participants had to recall names of people that they went to school with in their graduating class
Participants tested within 15 years of graduation were 90% accurate from photo recognition but 60% for free recall
Participants tested within 48 years of graduation were 70% accurate for photo recognition but only 30% for free recall
What are the evaluations of duration studies
Short term - Peterson + Peterson
- study used artificial stimuli therefore it lacked external validity
Long term - Bahrick et al
+ high external validity because researchers investigated meaningful info
What are the research studies for coding?
Baddeley
Participants were given a list of words and were asked to recall them in the correct order
Group 1- acoustically similar
Group 2- acoustically dissimilar
Group 3- semantically similar
Group 4- semantically dissimilar
When asked to recall immediately, they did worse with acoustically similar words - suggesting STM is coded acoustically
When asked to recall after 20 mins, they did worse with semantically similar words - suggesting LTM is code semantically
What are the evaluations of coding studies?
+ showed a clear difference between the two memory stores
- used artificial stimuli therefore it does not tell us about coding in different memory tasks so the study has limited application
What is the structure of the multi-store model?
Stimulus -> Sensory register -> STM -> LTM
Who proposed the multi-strore model?
Atkinson and Shiffrin
What is the sensory register?
Memory stores for the 5 senses
Iconic- visual info
Echoic- audio info
Coding-> specific to each store
Duration-> less than half a second
Capacity-> high
Information only passes through the memory system if it is paid attention to
What is the STM?
Coding-> acoustic
Duration-> about 18 secs (unless rehearsed)
Capacity-> 5-9 items
What is maintenance rehearsal?
When we repeat info to ourselves over and over again for it to stay in the STM
What is the LTM?
Coding-> semantic
Duration-> up to a lifetime
Capacity-> unlimited
What are the evaluations of the multi-store model?
Strengths:
Amnesia studies such as HM and Clive Wearing suggest that LTM and STM use different parts of the brain
Limitations:
There is evidence of more than one STM store -> there could be another short term store for non verbal sounds
Prolonged rehearsal is not only needed for transfer to LTM, elaborative rehearsal is also needed (this is when you link information to existing knowledge) so we can use elaborative rehearsal in order for info to be stored in the LTM
Read this PEELC paragraph on evaluations of the MSM
We can use the HM case study to provide evidence for the multi-store model. From research on HM’s brain, his hippocampus was found to be missing as it was removed when trying to help his epilepsy. As a result HM was not able to remember things he had just done but could still remember how to play the piano/write. This suggests that there are different stores of long term memory as suggested in the multi-store model. This is a valuable piece of evidence that supports the multi-store model, as only a part of HM’s brain was damaged, his whole long term memory was not destroyed showing that different parts of the brain code for different functions.
What are the 3 types of LTM?
Episodic
Semantic
Procedural
What is episodic memory?
Store for personal events
Explicit memory
Hippocampus is the part of the brain responsible
What is semantic memory?
Memory for facts and knowledge
Explicit memory
Temporal lobe is the part of the brain responsible
What is procedural memory?
Memory on how to do things -> riding bike/driving Implicit memory (difficult to explain in words) Cerebellum and motor cortex are the parts of the brain responsible
What are the evaluations for types of LTM?
Strengths:
There is clinical evidence from Clive Wearing and HM. Both their episodic memories were severely damaged but their semantic memories were unaffected as well as their procedural therefore this shows that there are different memory stores in the LTM and that one can be damaged but the others can be unaffected. HOWEVER because the researchers did not know how good Clive or HM’s memory was before it is difficult to make a comparison and the study may have lacked control of variables.
Real world application- this has allowed specific treatments to be developed to help the episodic memory in older people
Limitations:
Conflicting neuroimaging evidence- there is poor agreement on where each store of LTM is located
What is the structure of the WMM?
Visuo spatial sketchpad Episodic buffer Phonological
loop
What is the function of the central executive?
Monitors incoming data and allocates slave systems to task
- Limited capacity
- Does not store info
What is the function of the phonological loop?
Deals with auditory info -> coding is acoustic
2 subdivisions:
Phonological store: words you hear
Articulacy process: allows maintenance rehearsal
-Capacity of 2 seconds
What is the function of the visuo-spatial sketchpad?
Stores visual info 2 subdivisions: Visual cache -> stores visual data Inner scribe -> records arrangement of objects -Capacity of 3-4 objects
What is the function of the episodic buffer?
Temporary store for info which maintains a sense of time sequencing, links all sub-systems into one + links the WMM to LTM
-Capacity of 4 chunks
What are the evaluations of the WMM?
Strengths:
Clinical evidence from Shalice and Warrington’s study. KF had STM for auditory info but could process visual info normally -> KF’s phonological loop was damaged but his visa-spatial sketchpad was still intact which suggests that there are separate stores for audio and visual info.
HOWEVER they did not know if KF had other cognitive problems which could affect his scores on memory tasks which challenges evidence from this study
Dual task performance- Baddeley found that a person cannot carry out 2 visual tasks at one time but could carry out a visual and an audio task at the same time without any effect on performance. This means that there are separate slave systems for visual and audio info.
Limitations:
Lack of info on central executive therefore it challenges the validity of the WMM.
Studies that support the WMM use tasks that are not similar to everyday life and are carried out in highly controlled lab environments which challenges the validity of these studies.
What is interference?
Forgetting due to one memory blocking another which causes one/both to be distorted/forgotten?
What are the two types of interference?
Proactive interference-> older memory interferes with a newer one
Retroactive interference-> newer memory interferes with an older one
What is the study that provides evidence for interference?
McGeoch and McDonald Studies retroactive interference by changing the amount of similarity between two sets of materials. There were 6 groups of participants that had to learn different types of new lists: 1. Synonyms 2. Antonyms 3. Words unrelated to original ones 4. Consonant syllables 5. Three digit numbers 6. No new list -> control
-> The most similar materials produced the worst recall therefore interference is the strongest when memories are similar
What are some of the reasons why similarity affects recall ?
- Previously stored info -> makes newer info harder to store
- New info overwrites previous similar memories due to their similarities
What are the evaluations for interference?
Strengths:
Evidence of interference effects in more everyday situations -> Baddeley + Hitch:
Rugby players had to recall names of teams that they had played against in the rugby season. They found that players that played the most games had the poorest recall. This shows that interference occurs in everyday life which increases the validity of the theory. HOWEVER interference does not occur that often because two pieces of info have to be extremely similar to occur and this could have easily been achieve in a controlled lab environment, so there may be better explanations for forgetting
Limitations:
Interference is temporary and can be overcome by cues as found in Tulving’s study
What is retrieval failure?
Occurs when we don’t have the necessary cues to access memory
What is a cue?
A specific stimulus present when first storing the memory which ‘attaches’ to it to allow us to recall it later
What are the two types of retrieval?
Context dependant: Environmental cues are missing
State dependant: Internal cues are missing
What is the encoding specificity principle?
A cue has to be present at encoding (when learning the material) and present at retrieval. Therefore if cues available at encoding and retrieval are different, there will be some forgetting
What is the study related to context-dependent forgetting?
Godden and Baddeley Used deep sea diver participants who had to learn words under water or on land and then had to recall the words on land or in water. 4 conditions: Learn on land - recall on land Learn on land - recall underwater Learn underwater - recall on land Learn underwater - recall underwater Accurate recall was 40% lower in the non-matching conditions -> external cues were different than ones available when learning which caused retrieval failure
What is the study related to state-dependent forgetting?
Carter and Cassady
Gave a drug to participants which gave a mild sedative effect + made them drowsy. Participants had to learn lists of words/passages and recall them
4 conditions:
Learn on drug - recall when on drug
Learn on drug - recall when not on drug
Learn not on drug - recall when not on drug
Learn not on drug - recall when on drug
In non-matching conditions recall was significantly worse so when cues are absent there is more forgetting
What are the evaluations of retrieval failure?
Strengths:
Real world application- retrieval cues can help overcome forgetting in everyday situations + research can show us strategies we use in real life to improve our recall
Lots of research support- there is research that supports retrieval failure in both a lab and controlled environment BUT more research has suggested that context cues are not very strong in everyday life so these mat not explain everyday forgetting
Limitations:
May depend on the type of memory being tested- in Godden and Baddeley’s study participants had to recognise the word but not recall it. This suggests that retrieval failure only occurs when a person has to recall it but not recognise it so it may be a limited explanation for forgetting
What is the research on leading questions?
Loftus + Palmer
45 participants watched car accident clips and were asked questions -> critical questions that were leading questions but misleading info + word was changed for each of 5 groups (hit, bumped, contacted, collided, smashed) - they had to estimate the speed of the car
-‘contacted’ 31.8 mph
-‘smashed’ 40.5 mph
Leading question biases the eyewitness’ recall of event -> influences how they decide to answer
What is the research on post-event discussion?
Gabbert et al
Participants were in pairs and watched clips of the same crime but from different points of view + discussed what they saw
71% of participants mistakenly recalled aspects of the event that they did not see in the video but heard in discussion, control group was 0% (evidence of memory conformity)
Post-event discussion affects EWT because of memory contamination, a person’s testimony can be altered/distorted as they combine information from other witnesses with their own memories + people usually go along with each other due to conformity (they want social approval or believe that they are wrong)
What are the evaluations for misleading information?
Strengths:
Real world application to criminal justice system - police officers have to be careful in how they ask their questions therefore psychologists can help improve how the justice system works
Limitations:
EWT is more accurate for some aspects of an event than for others
Artificial tasks used in studies may tell us little about how leading questions affect EWT
What is anxiety?
State of emotional and physical arousal
- Worried thoughts/feelings of tension
- Increased heart rate/sweatiness
How does anxiety have a negative effect on recall? -> weapon focus study
Johnson and Scott
Participants believed they were taking part in a lab study. Low anxiety condition: heard a conversation and saw a man carrying a pen with grease on his hands
High anxiety condition: heard an argument and saw a man carrying a knife covered in blood
Participants had to pick out the man they saw from 50 photos, 49% in the low anxiety condition could identify him but only 33% in the high anxiety condition.
This shows the Tunnel Theory of memory - people’s attention narrows to focus on a certain aspect of a situation
What is the weapon focus effect? + how does it explain the relationship between EWT + anxiety?
People who focus their attention on the weapon involved rather than the face of the target
People who see a weapon are likely to have higher levels of anxiety so their recall becomes worse -> the physiological arousal stops us from seeing important cues
How does anxiety have a positive effect on recall?
Yuille and Cutshall
Actual shooting in a gun shop. 13 witnesses were interviewed 4-5 months after the shooting took place and these were compared with the police interviews taken at the time to see if they were accurate or not
Witnesses were accurate in what they said and there was little change in what they could recall after 5 months. Those who reported the highest levels of stress were the most accurate -> 88% compared to 75% for the less stressed group
This suggested that anxiety can enhance the accuracy of eyewitness testimony
What is the Yerkes-Dodson law?
Performance will increase with stress but only to a certain point where it will decrease drastically
What is the cognitive interview?
Method of interviewing to help eyewitnesses retrieve more accurate memories which has 4 techniques.
What are the 4 techniques used in the cognitive interview?
- Report everything
- Reinstate the context
- Reverse the order
- Change perspective
What is the enhanced cognitive interview?
Fisher et al
Focussing on the social dynamics of interaction -> knowing when to use eye contact
Reducing eyewitness anxiety and minimising distractions
Letting the witness speak slowly
Asking open questions
What are the differences between the standard police interview and the cognitive interview?
Cognitive interviews are more time consuming because a rapport between the witness and interviewer must be established + it also requires specialist training
What are the evaluations of the cognitive interview?
Strengths:
Evidence that the cognitive interview works, there have been 55 different studies which showed that the cognitive interviews had a 41% increase in accurate info compared to standard police interviews HOWEVER there were further findings to suggest that there was a higher percentage of inaccurate information with cognitive interviews -> may be more info recalled but it doesn’t mean it is correct
Limitations:
More time consuming as takes longer to train police officers compared to a standard interview. This means that not all police officers may have access to this specific type of training and it may be difficult to give all witnesses time they need to relax
Some elements of the cognitive interview may be more useful than others as there is evidence to suggest that not all of the elements are equally useful -> report everything and reinstate the context produced the best recall
