Memory (Paper 1) Flashcards
What are the three types of memory stores according to the MSM
Sensory register, short term memory and long term memory
The sensory register
The sensory register is continuously receiving information from al of our senses and is the first store in the multi store model.
Coding in the SR
Information is coded by the senses. For example, some sense receptors in the back of the eye code visual signals. Each sensory input has a separate sensory store: echoic (sound), iconic (vision), gustatory (taste), olfactory (smell), haptic (touch).
Capacity of the SR
Each sensory memory store has a large capacity. This is because we experience so many senses constantly that it needs a large capacity. However, it is hard to investigate the capacity accurately as there is so much information entering and leaving at all times.
Duration of the SR
Different sensory memory stores appear to have different durations. However, they all decay quickly as the store needs to constant,y make space for new information coming in. Therefore, it has very low duration (1 second or less)
Sperling (1960)
- Presented a grid of letters (3x4) for less than a second
- People on average recalled 4 letters
- They could not recall any more because the information decayed before they could report them all
The short term memory
This is the second memory store in the multi store model.
Coding in STM
Coding is the process by which the brain stores information from the senses. The STM is coded acoustically, remembering the sounds and words
Baddeley (1966) experiment for coding of STM
- He gave participants a list acoustically similar words in one condition and acoustically dissimilar words in the other condition.
- He found that people recalled less similar words (10%) compared to the dissimilar words (between 60 and 80%)
- He suggested that this means it’s coded acoustically due to the confusion caused when coding the words.
Capacity of STM
The capacity of STM is limited to between 5 and 9 items. However we can use chunking to increases capacity. Chunking is when you find a common link or meaning between a set of numbers or letters. For example you might split you phone number into three numbers at a time rather than remembering individual numbers.
Miller (1956)
Millers ‘magic number 7’ was the title of his memorable work. He discovered that on average people’s average span for letters and numbers was 7 +/- 2. He found this by reviewing data from previous experiments.
Jacobs (1887)
- He used the ‘digit span method’ to find limits of the STM. He found a mean span of 9.3 for numbers and 7.3 for letters.
- He conducted a experiment where the participant had to recall a longer list of numbers starting from 3 digits.
- Every time they got one right a new number with a extra digit would be produced for them to recall until they reached their limit.
Duration of STM
The duration of the STM is expected to be a maximum of 30 seconds. However, this can be extended by repetition or rehearsal. This is the function of the rehearsal loop in MSM.
Peterson and Peterson (1959)
- They used trigrams (a set of three consonants) to test retention.
- They then asked participants to learn the trigram and count backwards from a three digit unnumbered until told to stop.
- They tested recall of the trigrams after 3,6,9,12,15 and 18 seconds which they called the retention level.
- They found STM duration declined rapidly beyond 18 seconds and the counting back prevented them from being able to rehearse the three consonants.
Long Term Memory
This is the last part of the multi store model. It stores information over a long period of time. Throughout our lives LTM allows us to remember important people, certain routines and our knowledge base.
Coding in LTM
The coding in LTM is semantic coding. This means that information is remembered through meanings rather than visually or acoustically. When we understand the meaning of something it is more likely to be remembered.
Capacity of LTM
The capacity of LTM is thought to be unlimited, depending on individual differences. However, decay, interference and illness may result in the loss of information.
Duration of LTM
The duration of information in the LTM is unlimited. Many people remember people, events and facts for a lifetime.
Bahrick et al (1975)
- Conducted an experiment from a high school in America. He asked students 14 years after graduation to remember names and faces from their yearbook.
- He found there was a 90% accuracy.
- However, he did the same experiment on students who had graduated 48 years ago.
- They had 70% accuracy when matching names to faces.
- However, the other condition only had 30% accuracy when asked to free-recall names without faces.
- This shows that without frequent recall information can decay in the LTM.
- Recognition is much easier than free-recall, could explain why exams are challenging
Who was the the Multi Store Model introduced by
- Introduced by Atkinson and Shiffrin (1968)
- Cognitive explanation
- Uses analogy of a computer and the concepts of encoding and retrieval to understand memory
3 types of memory stores involved
Sensory register, short term memory and long term memory
How does the Multi Store Model work
- Information reaches sensory register from the senses
- We select what to pay attention to and pass this on to the STM, most information is lost at the sensory register
- The rehearsal loop (e.g. revision) keeps information in the STM for long enough it to be passed into the LTM
- Lack of rehearsal can result in the information being lost in the STM
- The information in the LTM lasts forever and can be used by the STM by retrieval, when in the STM information can be used
The working memory model
Baddeley and Hitch (1974) thought that STM is more complex than Atkinson and Shiffrin (1968) had proposed. They felt that in STM more pieces of information are held simultaneously for a few seconds while the brain decides what is relevant or not. There are 3 main components of WMM and they all code information differently
Central executive
The central executive is the decision making aspect of the WMM. There are 2 slave systems that the central executive allocates tasks to. It has very limited storage capacity.
Phonological loop
This is the first slave system. It deals with auditory information and preserves the order in which it arrives. Subdivided into:
- The phonological store, which stores the words that you can hear
- Articulatory process is like a ‘inner voice’ that allows us to repeat information in our head to help us to remember
Visio-spacial sketchpad
The VSS stores visual and/or spatial information when required. For example, if you are asked to picture how many windows there are on your house you will visualise it in your head. It has limited capacity (3 or 4) objects.
Logos (1995) subdivided into 2 parts :
-Visual cache, which stores visual data
-Inner scribe, records the arrangement of objects e.g. memorising a route
Research support for PL
Baddeley et al (1975) demonstrated word length effect by asking participants to remember a list on long and short words. They could hold fewer long words in the PL because it has limited capacity. However if they had to speak out loud when remembering the short words they struggled because the PL storage was being taken up by speech.
Research support for the VSS
Gathercole and Baddeley (1993) asked participants to track a moving light at the same time as describing the angles on a letter F. They compared results to participants completing a visual and verbal task simultaneously. When two separate stores were involved performance was better. This supports evidence of two separate stores.
The problem of central executive
No one has been able to pin down a part of the brain that could be the CE. It could be possible to find in the future with better neuro technology.
Dual task experiments
This proved evidence of the model as two different stores working at the same time showed better performance than the same store working the same as the two separate stores combined.
Types of Long Term Memory
- Tulving (1985) was one of the first cognitive psychologists to realise that the MSM’S view of LTM was too simplistic and inflexible.
- Tulving proposed that there was in fact three LTM stores, containing different types of information in each.
Episodic memory
These are memories of events in life. They are usually processed deeply because they have meaning and emotional content. It requires some conscious effort to recall them
Semantic memory
These are memories that make up our knowledge. As we mature, we accumulate knowledge through facts, events and actions. We store those that have meaning for us, and it requires some conscious effort to recall them
Procedural memory
This is memory for how to do things, such as ride a bike, skip, skate, sew, knit. Once learnt, it is often automatic and requires little effort to recall.
Prefrontal cortex
Involved in the storage of short term memories
Hippocampus
Plays a pivotal role in the formation of new long term semantic and episodic memories
Clive Wearing evidence for different types of LTM
- Suffered viral infection in the brain due to amnesia which meant his episodic memory was severely impaired.
- He could not recall personal events that had happened in the past
- However his semantic memories and procedual memories were relatively unaffected (he remembered how to play the piano)
HM evidence for different types of LTM
- HM had brain surgery for epilepsy which removed his hippocampus
- Hippocampus is vital for creating new memories
- Therefore he was unable to retain new memories for more than a few minutes
- However, he still remembered information and facts from before his surgery due to his semantic and procedual memory being intact
Neuro evidence
- Using PET scans, Tulving et al 1994 discovered that left prefrontal cortex is involved in semantic memory and the right prefrontal cortex is involved in episodic memory
- This was found as he asked participants to complete various tasks whilst there brains were being scanned
Evaluation for types of LTM
Positive: more effective help for stroke patients, strong evidence due to brain scans which increases reputation of psychology as a science
Explanations for forgetting: interference
Forgetting is a retrieval failure when material stored in the LTM is lost temporarily or permanently despite conscious effort to recall it. There are two explanations for this: interference and retrieval failure
Retroactive interference
- Old information being interfered with, New info ‘overwrites’ previously stored info
- For example, learning German then learning french which disrupts the memory of German. You could use a french word when speaking German
- Learn A, the learn B, try to remember A but B interferes
Proactive interference
- New information being interfered with. Something you have already learnt disrupts something you are trying to learn.
- Difficulties learning your new phone number as you keep remembering your old one.
Postman (1960)
- Aim: investigate how retroactive interference affects learning.
- Method: lab experiment, P’s split into two groups and both had to remember a list of paired words. Experimental group had to learn a new list whereas control group didn’t
- Results: recall of first list from control group was better than experimental group as there was no interference from new information learnt
Baddeley and Hitch (1977)
- They asked rugby players to recall the names of teams they had played against earlier in the season
- For various reasons including injuries and suspensions most players they interviewed had missed some games. So for one player the last game might have been last week, while for another it was two months ago.
- Baddeley and Hitch found that recall for the last game was equally good whether that game was played some time ago or last week. This shows that incorrect recall was not due to decay (the passage of time) but was related to the number of intervening games
- Natural experiment, ecological validity
Evaluation of interference
- Lots of lab experiments with high control and standardised procedures mean research is reliable
- Can be applied to real life, e.g.B Baddeley and Hitch field exp
- However there is a lack of ecological validity in Postman’s exp as the experiment was not done in a natural environment
Cue dependent forgetting
Absence of cues can cause a failure to retrieve a memory from the LTM store. The theory proposes that when we learn information we also encode the context (external cues) and mental state (internal cues).
Tulving 1983
For a cue to be effective, it needs to be present when learning and recalling. If the cue is different then there will be a failure to retrieve a memory from the LTM
Godden and Baddeley 1975 (context dependent forgetting)
-Got 18 divers to learn lists of 36 words on land or under water.
-When the learning and recall conditions matched (e.g. learnt list on land and recall list on land) performance was better
-This proves that context dependent forgetting is a thing
Evaluation: limited eco validity as environment was familiar to their every day life, also experiment was disrupted due to weather
Goodwin et al 1969 (state dependent forgetting)
- 48 male medical students were randomly assigned to 4 groups in a 2 day experiment
- Sober both days, intoxicated both days, intoxicated day 1 and sober day 2, sober day 1 and intoxicated day 2
- Participants had to perform 4 tests: avoidance task, verbal rote learning task, word association, picture recognition
- Found that more errors were found when intoxicated, and sober on both days performed best in all tasks
- intoxicated on both days and sober in both days had better performance than the other two in day 2
Misleading information
Leading questions and post event discussion are two factors that can affect the accuracy of eye witness testimony
Leading questions
-Leading questions such as ‘did you see the broken glass’ rather than ‘what did you see’
-Response bias: when a person gets a leading question it biases their response without changing the memory
Memory substitution: when a person gets a leading question it actually changes the stored memory
Loftus and Palmer 1974
- 45 student participants shown short video clips
- Split into 5 groups
- All the participants were asked ‘how fast were the cars going when they ——- each other
- Each group were given a different verb from the experimenter ‘smashed, collided, bumped, hit or contacted’.
- They were then asked to estimate the speed of the car, when the harsher verbs were used such as smashed the mean estimation of speed was higher compared to a low estimation when contacted was used
Post event discussion
When witnesses discuss what they saw after a crime their memory can become become contaminated by what others say. In court witnesses cannot speak to each other until the trial is completed.
Memory conformity
People being influenced by another person’s report. This results in the individual’s memory report becoming more similar to another
Gabbart et al 2003
-Investigated the effect of post-event discussion on the accuracy of eyewitness testimony.
-Sample consisted of 60 students from the University of Aberdeen and 60 older adults recruited from a local community.
-Participants watched a video of a girl stealing money from a wallet. The participants were either tested individually (control group) or in pairs (co-witness group).
-The participants in the co-witness group were told that they had watched the same video, however they had in fact seen different perspectives of the same crime and only one person had actually witnessed the girl stealing.
-Participants in the co-witness group discussed the crime together.
-All of the participants then completed a questionnaire, testing their memory
of the event.
-Gabbert et al. found that 71% of the witnesses in the co-witness group recalled information they had not actually seen and 60% said that the girl was guilty, despite the fact they had not seen her commit a crime.
-These results highlight the issue of post-even discussion and the powerful effect this can have on the accuracy of eyewitness testimony
Anxiety and eye witness testimony
Anxiety has a big effect on eye witness testimony, when a crime happens you are usually in an emotional state and this can affect the accuracy of eye witness testimony.
Johnson and Scott
Aim: investigate the effect of a weapon on eye witness testimony accuracy
Method (pen/knife study): participants waited in a reception area and were exposed to either:
1. a heated argument in the next room, a crash of equipment and then a man emerged holding a paper knife
2. a disagreement about lab equipment in the next room and then a man left holding a pen
Participants had to identify the man from 50 photos
Results: Those in the pen condition were correct 49% of the time. Those in the knife condition were correct 33% of the time.
Conclusion: Anxiety decreased the effectiveness of eye witness testimony, as participants were focusing on the knife rather than the mans face. This is the weapon focus phenomenon.
Optimum level
It could be that there is an optimum level for anxiety. Recall improves up to a point and then declines if anxiety continues to increase. The optimism point on the graph is perfect for eye witness testimony.
The cognitive interview
- Geiselman et al developed the cognitive interview, identifying four key principles that they believed would enhance recall:
- Context Reinstatement: when a person mentally recalls the context of the event. For example a person may remember the time, weather or who they were with. These can act as a recall trigger
- Report everything: where a person recalls every detail they can remember, even those that may seem trivial
- Recall from changed perspective: when a person considers the event from someone else’s point of view, for example, they might consider what the offender saw
- Recall in reverse order: where a person recalls a event in reverse chronological order
