2014
Memory, attachment and revision methods / I’ve lovingly created this for you -so use it !
Memory
Capacity in STM (Miller 1956): 7±2
Jacobs (1887)Participants were read lists of either words or numbers that they had to recall immediately after presentation. Jacobs gradually increased the length of these digits etc until the participant could only accurately recall the information, in the correct order, on 50% of occasions. Recall has to be in the correct order (serial recall).
X N J P T C B D L Y Q H
Findings
Jacobs found a difference between capacity for numbers and for letters. On average participants could recall 9 numbers but only 7 letters.He also noticed that recall seemed to increase with age. Eight year olds being able to recall an average of 7 digits whereas by the age of 19 recall had increased to 9 digits. (NB later studies have suggested that capacity does eventually start to decrease in much older participants).
Conclusion
STM has a capacity of between 5 and 9 items of information and as age increases we appear to develop better strategies of recall.
A02
Later studies (Miller 1956) have supported Jacobs’ findings and conclusions. Miller published his findings in an article entitled “The magic number seven, plus or minus two.”
Miller and others have also discovered that chunking can increase capacity (BBC or 01858 becomes one chunk of information rather than 3 or 5 distinct chunks).
Like most memory research this lacks ecological validity. You’re using your memory for an artificial task. Does this tell us anything about how memory works in everyday life
Peterson and Peterson (1959) – Duration in Short Term Memory
AIMS:
- They aimed to study how long information remains in short term memory, using simple stimuli and not allowing the participants to rehearse the material presented to them
- They wanted to test the hypothesis that information not rehearsed is lost rapidly from short-term memory.
PROCEDURES:
- They used the ‘Brown-Peterson’ technique.
- On each trial participants were presented with a trigram consisting of 3 consonants e.g. BVM, CTG which they knew they would have to recall in the correct order.
- Recall was required after a delay of 3, 6, 6, 12, 15, or 18 seconds.
- Between the initial presentation of the trigram and the time participants were asked to recall, they were told to count back in threes from a random 3 digit number e.g. 866, 863, 860… thisINTERFERENCE TASK was done to prevent rehearsal.
- Participants were tested repeatedly with the various time delays and the effect of the time delay on memory was assessed in terms of the number of trigrams recalled.
FINDINGS:
- There was a rapid increase in forgetting from the STM s the time delay increased.
- After 3 seconds 80% of the trigrams were recalled.
- After 6 seconds 50% were recalled
- After 18 seconds fewer than 10% of the trigrams were recalled.
- Therefore very little information remained in the STM for more than 18 seconds.
CONCLUSIONS:
- The findings suggest strongly that information held in the STM is rapidly lost when there is little or no opportunity for rehearsal.
- Thus information in the STM is fragile and easily forgotten
EVALUATION:
- They used artificial stimuli (i.e. trigrams), which have very little meaning and therefore the experiment lacks mundane realism and external validity.
- The participants were given many trails with different trigrams so may have become confused.
- Peterson and Peterson only considered STM duration for one type of stimulus, and did not provide information about duration of STM in other kinds of stimuli e.g. pictures, smells, melodies.
+ It was a well controlled lab experiment, which allows a cause and effect relationship to be established.
+ Repeated measures design
Bahrick et al. (1975) – Duration in Long Term Memory
AIMS:
- Bahrick et al aimed to investigate the duration of very long term memory (VLTM), to see if they could last over several decades and thus support the assumption that the duration of long term memory can last a life time.
- They aimed to test VLTM in a way that showed external validity by testing memory for real-life information.
PROCEDURES:
- 329 American ex-high-school students aged from 17 – 74 were used – It was an opportunity sample.
- They were tested in a number of ways:
- Free recall of the names of as many former class mates as possible
- A photo recognition test, where they were asked to identify former classmates in a set of 50 photographs, only some of which were classmates.
- A name recognition test
- A name and photo matching test
- Participants accuracy (and thus duration of memory) was assessed by comparing their responses with high-school year books containing pictures and names of all the students in that year.
FINDINGS:
- 90% accuracy in face and name recognition (even with participants that had left high school 34 years ago)
- After 48 years of leaving this accuracy of name recognition declined to 80% and for face recognition it was 40%
- Free recall was considerable less accurate; 60% accurate after 15 years and only 30% accurate after 48 years.
CONCLUSIONS:
- The findings show that classmates were rarely forgotten once participants were given recognition clues. Thus the aim of very long term memory was supported.
- The research demonstrates VLTM for a particular type of information, it cannot be concluded that VLTM exists for all types of information.
- The finding that free recall was only 30% after 48 years indicates that memories were fairly weak.
EVALUATION:
- + This study provides evidence for the assumption that information can remain in the LTM for very long periods of time.
- - Classmates faces and names are a very particular type of information. They might have emotional significance, and there was a great deal of opportunity for rehearsal, given the daily contact they would have experienced. The same is not true for other types of information and therefore the findings cannot be generalised to other types of information.
- + Bahrick’s research has high mundane realism as he asked participants to recall real life memories, and therefore the research is more representative of natural behaviour and so has high external validity, and it may be possible to generalise the findings to other settings.
Baddeley (1966) – Encoding of Short Term Memory and Long Term Memory
AIMS:
- Baddeley aimed to investigate how short term memory and long term memory is encoded.
PROCEDURE:
- Participants were given four sets of words to recall in order.
- For the STM task they had to recall them immediately following presentation.
- LTM task they had to be recalled following a longer time interval.
- Set 1 were words that all sounded similar, for example: cat, mat, cap, map…
- Set 2 were words that sounded differently for example: dog, bin, cup, pen….
- Set 3 were words of similar meaning for example: big, large, huge, vast…
- Set 4 were words of different meaning for example: huge, good, light, blue….
- The researchers then recorded the how many mistakes were made in recalling the sets of words.
FINDINGS:
- In the STM procedure participants made significantly more mistakes on words that sounded alike so for example would confuse cat and cap etc. Similarly with letters, S and X would be confused as would M and N and P and B etc.
- In the LTM procedure participants were far more likely to confuse words of similar meaning replacing huge with vast or night and dark etc.
CONCLUSION:
- STM information is encoded by its sound (acoustically) so when we recall information from STM similar sounding words get confused.
- LTM information is encoded by its meaning (semantically).
EVALUATION:
- It is an artificial task therefore it lacks ecological validity since it doesn’t relate to how memory is used everyday.
- There were demand characteristics which is when P’s change their behaviour in line with what they think the study is about.
+ It was done in a controlled environment, so there were no extraneous variables which could’ve affected the findings of the experiment.
The Multi-store Model of Memory - Atkinson and Shiffrin (1968)
Atkinson and Shiffrin argued that there are three memory stores:
- sensory store
- short-term store
- long-term store
- According to the theory information from the environment is initially received by the sensory stores.
(There is a sensory store for each sense.) - Some information in the sensory stores is attended to and processed further by the short-term store.
- In turn some information processed in the short-term store is transferred to the long-term store through rehearsal or verbally repeating it. The more something is rehearsed the stronger the memory
trace in the long-term memory. - The main emphasis of this model is on the structure of memory on rehearsal.
EVALUATION:
+ Case studies of brain damaged patients lend support to the multi-store model; they support the view that there are two different memory stores.
+ Glanzer and Cunitz found that when rehearsal is prevented, the recency effect disappears.
+ There is evidence that encoding is different in short term and long-term memory. For example Baddeley found that acoustic or sound encoding was in the short-term memory and semantic or meaning encoding was in the long-term memory.
+ There are huge differences in the duration of information in the short term and long term memory. Unrehearsed information in the short-term memory had vanished after about 20 seconds (Peterson & Peterson). In contrast some information in the long-term memory is still there 48 years after learning (Bahrick et al.)
- The model argues that the transfer of information for short term to long-term memory is through rehearsal. However in daily life people devote little time to active rehearsal, although they are constantly storing new information into the long-term memory. Rehearsal may describe what happens in laboratories but is not true to real life. Craik & Lockhart suggest that it is the level at which we process information that determines how well we remember it. Rehearsal represents a fairly shallow processing level.
- This model is oversimplified. It assumes that there is a single short-term store and a single long-term store. These assumptions have been disproved, by evidence such as that from the studies of brain damages patients. KF had a motorcycle accident that left him with a severely impaired STM but he could still make new long-term memories. Also Clive Wearing, another brain damaged patient, could still play the piano, speak and walk.
Therefore it makes sense to identify several long-term memory stores; episodic memory, semantic memory, declarative knowledge and procedural knowledge. Atkinson and Shiffrin focus exclusively on declarative knowledge and had practically nothing to say about procedural knowledge e.g. skills and learning.
Working Memory Model - Baddeley and Hitch (1974)
Episodic buffer was added by Baddeley in 2000. The central executive has no storage of its own and the other two stores hold either visual or auditory data. Baddeley realised that there needed to be a store that could hold and coordinate information from all three other stores as well as from LTM.
EVALUATION:
- + Active process: It sees memory as an active process and not merely a passive store.
- - Rehearsal: It only considers rehearsal to be important in the phonological loop. It is widely considered that the multi-store model does place too great an emphasis on rehearsal in transferring information to STM.
- + PET scans (Positron Emission Tomography), show that different parts of the brain are active when different parts of the system are in use. This provides further evidence for distinct components. The central executive seems to reside in the frontal cortex and the scratch pad in the right side of the occipital lobe, known to be associated with vision.
- + Amnesiac case studies: A single component STM is unable to explain the case of KF, who, following a motorbike accident suffered impairment of his STM. Shallice & Warrington (1974) showed that although his memory for verbal material was poor his memory for visual information was unaffected. The working memory model can explain that it was damage to the articulatory loop with the sketchpad remaining intact.
- + Baddeley (1986) found that patients with damage to their frontal lobe had problems concentrating suggesting damage to the central executive (researcher biased)
Flashbulb Memories – Brown and Kulik (1977)
A flashbulb memory is a long lasting, detailed and vivid memory of a specific event and the context in which it occurred. The event is important and emotionally significant e.g. a national or personal event. It is as if a flash photograph was taken at the very moment of the event with every detail indelibly printed in memory. Flashbulb events don’t have to be negative or to concern international events. However nearly all studies of flashbulb memories have focused on dramatic world events. Brown and Kulik suggested that flashbulb memories were distinctive because they were both enduring and accurate
Evaluation of Flashbulb Memories
- Brown and Kulik had no way of knowing if the participants Flashbulb memories were accurate / reliable.
McCloskey , Wible, and Cohen wanted to test the reliability of flashbulb memories, they interviewed people shortly after the explosion of the space shuttle Challenger and then re-interviewed the same people 9 months later.
They found that participants did forget elements of the event, and showed some inaccuracies in their recall. This suggests that flashbulb memories are subject to forgetting in the same way that other memories are.
Conway et al disagreed with McCloskey et al, they stated that the Challenger explosion was not a very good example of flashbulb memory as it did not have important consequences in the lives of those who were interviewed, and therefore lacked one of the central criteria for flashbulb memory.
Loftus (1975)
- The aim of this study was to discover the influence of misleading information on eye-witness testimony.
- 150 participants were shown a film of a car accident.
- Group 1: asked 10 questions which were consistent with the original film.
- Group 2: asked the same questions apart from 1 question which was ‘How fast was the white sports car going when it passed the barn?’. This was a misleading question as it suggested that there was a barn in the film, even though there wasn’t one.
- A week later both groups were asked ‘did you see the barn?’.
- 17.3% of the group that were provided with the misleading question, gave the incorrect answer of ‘yes’. Only 2.7% of the other group said ‘yes’.
- For the group provided with the misleading question, it is likely that they formed an image of a barn, which over time became integrated with their mental representation of what they had actually seen in the film.
- This shows that misleading information can alter the mental representation a witness has of an event, consequentially reducing their accuracy.
Eyewitness Testimony (Loftus and Palmer) (1975):
AIMS:
- To test their hypothesis that eyewitness testimony is fragile and can easily be distorted.
- Loftus and Palmer aimed to show that leading questions could distort eyewitness testimony accounts via the cues provided in the question.
- To test their hypothesis, Loftus and Palmer asked people to estimate the speed of motor vehicles using different forms of questions after they observed a car accident. The estimation of vehicle speed is something people are generally quite bad at, so they may be more open to suggestion by leading questions.
PROCEDURES:
- 45 American students formed an opportunity sample
- This was a laboratory experiment with 5 conditions. Each participant only experienced one condition (an independent measures design)
- P’s were shown a brief film of a car accident involving a number of cars. They were then asked to describe what happened as if they were eyewitnesses.
- After they had watched the film, the P’s were asked specific questions including the question ‘about how fast were the cars going when they (hit/smashed/collided/bumped/contacted –the five conditions) each other?’
- Therefore, the IV was the wording of the question and the DV was the speed reported by the P’s.
- A week after the P’s were shown the film, they were asked ‘Did you see any broken glass?’ when there actually was no broken glass in the film
FINDINGS:
- Loftus and Palmer found that estimated speed was influence by the verb used. The verb implied information about the speed, which affected the P’s memory of the accident.
- Those who were asked the question where the verb used was ‘smashed’ though the cars were going faster than those who were asked the question with the verb ‘hit’ as the verb.
- The mean estimate when ‘smashed’ was used was 41mph. compared to 34mph when ‘hit’ was used.
- Therefore, the P’s in the ‘smashed’ condition reported the highest speeds, followed by ‘collided’, ‘bumped’, ‘hit’, and ‘contacted’ in descending order.
- In answering the follow up question, a higher percentage of P’s who heard ‘smashed’ said that they had seen broken glass than those who heard ‘hit’. These percentages were 32% compared with 14%.
CONCLUSIONS:
- The questions asked can be termed ‘leading’ questions because they affected the P’s memory of the event.
- The answer to a leading question is in the question – the question contains information about what the answer should be.
- Therefore, language can have a distorting affect on Eyewitness testimony, which can lead to inaccurate accounts of witnessed events.
- It is possible that the memory had been reconstructed. However, it is also possible that the original memory may have been replaced or experienced interference. This has important implications for the questions used in police interviews of eyewitnesses.
EVALUATION: