Memory

Memory

1. A model is a representation of something. Memory is the process of storing and retrieving information about the past.

2. The Multi-store Model

   • 1) Sensory Memory - a set of limited capacity, specific stores, which if aren't rehearsed will decay (disappear). The encoding for the SM is that it takes information from one of the sense organs and holds it in that same form. The capacity is 1 out of 2 pieces of information at a time. The duration time for the memory is a split second of a fraction.
   • Encoding - the way in which information is represented in the memory store.
   • Capacity - the amount of information tha't can be held in memory at any one time.
   • Duration - the length of time that memories can be held.
   • 2) Short-term Memory - a temporary store for small amounts of information to be kept for brief periods of time. It is encoded acoustically and has limited capacity (Miller's magical number 7 > 7+/- 2). The duration is between 0 - 18 seconds.
     • Jacobs (1887) wanted to find out how much information the STM can store. To measure the digit span he gave the participants digits for them to recall out loud in the correct order. If this is correct, the number of digits used increases by one each time until the participants cannot recall the order correctly. He found that the mean span for digits across all participants was 9.3 items and the mean span for letters was 7.3. To expand STM, we must chunk numbers and letters together so it takes up fewer spaces in the STM and also chunking it meaningfully by organising it with existing knowledge, e.g. abbreviations. A limitation of this study would be that it was conducted a long time ago - technology and research methods have changed (outdated).
     • Miller (1956) further supported this by looking at past research on STM concluding we can hold up to 7+/- 2 pieces of information. However, Miller did not specify how large each ‘chunk’ of information could be and therefore making it unable to conclude the exact capacity of short-term memory. Consequently, further research is required to determine each size of information ‘chunks’ to understand the exact capacity of short-term memory.
   • 3) Long-term Memory - a permanent store where limitless amounts of information can be stored for long periods of time. It is encoded mainly semantically and has an unlimited capacity. It can be stored for long periods of time.
     • Bahrick (1975) explored the number of times memory can be retrieved by asking American high school graduates to put names to faces in their high school yearbook. They had to match pictures, match names and recall names with no pictures. He found that the participants recalled well up to around 34 years old - performance was better on recognition tasks than on recall tasks. After 47 years, participants dipped in remembering. This concludes that the more time passes, the fewer amount of memories retained. However, it is difficult to decide whether this deficit is due to the passage of time or due to ageing effects in the brain of older people. A strength is that it has high external validity because real-life meaningful memories were studied.
   • Evaluation
     • 1) Glanzer and Cunitz (1966) - The Serial Position Effect: Words were read out to participants and they were asked to recall them straight after. The results showed that words from the start were remembered due to LTM and words at the end were remembered by the STM. Therefore words in the middle were lost. This is the primacy effect (remembered at the beginning) and the recency effect (remembered at the end). When participants remember primary and recent information, it is thought that they are recalling information from two separate stores (STM and LTM).
     • 2) MRI scans show which parts of the brain are being used when certain tasks are carried out. They take an image of the brain and see what area is involved in specific tasks. The prefrontal cortex is active when individuals work on tasks in STM. The hippocampus is active when the LTM is engaged. This supports the fact that STM and LTM are separate.
     • 3) HM suffered from severe epilepsy when surgeons carried out an operation to remove most of his hippocampus. Since then his personality and intellect remained intact but he could no longer form new long memories but could remember things before his surgery. This suggests the hippocampus functions as a 'gateway' through which new memories must pass through before entering permanent storage in the brain.

3. The Working Memory Model

   • 1) Central Executive: This manages attention, and controls information from the two ‘slave stores’. It has limited capacity and can switch attention between tasks. It coordinates the activity needed to carry out more than once processing task at a time.
     • Phonological Loop has two parts: Phonological Store (inner ear) - This holds information in a speech-based form, such as spoken words. Articulatory Process (inner voice) - any language presented visually to convert to a phonological state, for storage in the phonological store.
       • Baddeley, Thompson and Bucannan (1975) - Word Length Effect: They presented words for very brief periods of time. One condition had 5 words with one syllable familiar. The other condition had 5 polysyllabic words. The average correct recall over several trials showed participants remembered the short words much better - called the 'word length effect'. The fact that people cope better with short words than long words in the STM shows that the capacity depends on the length of words and not the amount.
     • Visuo-Spatial Sketchpad - this temporarily retains visual and spatial information: Visual cache - looks at things in their form and colour. Inner scribe - remembers objects as they are.
       • Baddeley et al (1973): Participants were given a visual tracking task to track a moving line with a pointer at the same time as one of the other given tasks: to describe the angle of the letter F and to peform a verbal task. They performed better in the second task because they were able to use two different systems simultaneously rather than conducting a task, where they are competing for the same attention.
     • Episodic Buffer - acts as a 'backup' store which communicates with both long-term memory and the components of working memory.
     • Activity in the CE should be increased when an individual has to perform 2 tasks simultaneously (dual-task) rather than one after the other (single task). Bunge (2000) used fMRI scans to see which parts of the brain are most active when participants were carrying out 2 tasks. The same brain areas were active during dual or single-task conditions. There was significantly more activity in the brain when two tasks were being performed indicating there was an increased demand for attention when performing two tasks simultaneously. This supports the existence of the four different components of the WMM.
     • Evaluation
       • + Brain imaging studies have suggested that the components of WM are related to distinct areas of the brain. For example, Cohen et al (1997) found that there was higher brain activity in a part of the brain known as the prefrontal cortex during a task when the CE was working.
       • + The model was developed based on evidence from laboratory experiments, so confounding variables could be carefully controlled to produce reliable results (that can be replicated).
       • - Despite providing more detail of STM than the multi-store model, the WMM has been criticized for being too simplistic and vague, e.g. it is unclear what the central executive is, or its exact role in attention.

4. Types of LTM

   • Semantic Memory: General knowledge, declarative (explicit). Usually starts as the episodic memory but generally loses association with particular events, so only the knowledge remains.
   • Epsiodic Memory: Personal recollections, explicit memory. They include details of events, the contect in which the event took place and emotions associated with it.
   • Procedural Memory: Knowing how to do something -> they usually describes our implicit knowledge of tasks that usually do not require conscious recall to perform them.
   • Evaluation
     • CW and Hm: Both suffered from memory loss. Their episodic memory was severely impaired as a consequence of amnesia. They had difficulty recalling events that happened from their pasts.
       • Their semantic memories were unaffected, e.g. they still knew the meaning of words. HM couldn't remember stroking a dog 30 minutes ago, previously owning a dog in the past, but never needed the concept of dog explained to him over and over again.
       • Their procedural memories were also intact. They both knew how to tie their shoelaces, how to walk and speak. CW was a professional musician and knew how to read music, sing and play.
       • Shows that there are different types of LTM stored as some types could not be remembered. Also, the memories are stored in different places because their hippocampus was damaged, but other memories as such were intact.
     • + Evidence from brain scan studies to support different types of LTM being stored in different parts of the brain.
       • Tulving got p's to perform various tasks while their brains were being scanned using a PET scanner. They found that episodic memories were recalled from the right prefrontal cortex and semantic memories were recalled from the left prefrontal cortex. Procedural memories were recalled from the cerebellum and the basal ganglia.
       • This is a strength as brain scans are scientific. (unbias).
     • Real Life Application: Belleville demonstrated that episodic memory could be improved in older people who had a mild cognitive impairment. The trained p's performed better on a test of episodic memory after training than the control group.
       • Benefit of being able to distinguish between them -> e.g. gives people a better life experience.

5. Explanations For forgetting

   • Interference
     • When one memory disturbs the ability to recall another - more likely to happen if the memories are similar.
       • Retroactive Interference: When more recent information gets in the way of trying to recall older information, e.g. calling tour ex by your new partner's name - newer memories interfere with older memories.
       • Proactive Interference: When old information prevents recall of newer information, e.g. when trying to recall a new phone number, the old number previously learnt interferes with recall - older memory interferes with a new one.
       • Underwood and Postman: Participants divided into two groups and used a paired associate learning task to test the effect of interference. Group A were asked to learn a list of word pairs, and then asked to learn a second list where the word pairs were different. Group B only learn the first list of word pairs. Both groups were asked to recall. Group B recalled the first list more accurately as no interference occured with previously learnt words.
       • Evaluation
         • Poor ecological validity: Like much of memory research there is a problem with the validity of the research that supports the theory. It is predominantly laboratory based and therefore does not test everyday recall.
         • Limited scope: This theory only can explain lack of recall when information in a similar format prevents recall. This means that there are many types of recall that are not explained by this theory.
         • Intuitively correct: Most people can think of times when interference in both directions have occurred. This means that the theory makes sense and there are plenty of everyday examples of it occurring.
   • Retrieval Failure due to Absence of Cues
     • When information is initially placed in memory, associated cues are stored at the same time. Forgetting in LTM is usually down to retrieval failure (lack of accessability, NOT AVAILABILITY).
       • There are two types of cues: Cues which are linked meaningfully to the information to be remembered, and cues which are not.
         • Context-dependent forgetting can occur when the environment during recall is different from the environment you were in when you were learning.
           • Godden and Baddely carried out a study of deep sea divers working underwater. The divers learned lists of words in different conditions: 1. Learn on land, recall on land. 2. Learn on land, recall underwater. 3. Learn underwater, recall on land, 4. Learn underwater, recall underwater. They found that the environmental contexts of learning and recall matched, whereas in the other conditions they did not. Accurate recall was 40% lower in the non-matching consitions. This shows the context acts as a cue for remembering words.
         • State-dependent forgetting occurs when your mood or physiological state during recall is different from the mood you were in when you were learning.
           • Goodwin et al conducted a study on 48 male medical students who participated on day 1 in training sessions and day 2 on testing. They were randomly assigned to four groups. Group 1 (SS) was sober both days. Group 2 (AA) was intoxicated both days. Group 3 (AS) was intoxicated on day 1, and sober on say 2. Group 4 (SA) was sober on day 1 and intoxicated on day 2. They intocicated groups had 100ml of alcohol in their blood and showed signs of intoxication.
             • The p's performed 4 tests: an avoidance task, a verbal rote-learning task, a word-association test and a picture recognition task. More errors were made on day 2 in the SA and AS condition than the others, but this was not the case for picture recognition tests. The SS p's performed best in all tasks.
               • When people encoded information when toxicated, they were more likely to recall it in the same state.

6. Eyewitness Testimony

   • A legal term, referring to the use of eyewitnesses to give evidence in court.
   • Misleading Information: A leading question is a question that either suggests to the witness what answer is desired or leads them to the desired answer.
     • Loftus and Palmer: They aimed to investigate how accurate/inaccurate memory was - see the effect of language upon estimates of memory.
       • Experiment 1: To see if the speed estimated by p's upon watching a video of a car crash would be influenced by the wording of the question asked. The participants were 45 American students and they each watched 7 films depicting a traffic accident. Each film lasted for 5-30 seconds and presented in different orders to each group. After each film they were given a questionnaire, the first question asked the students to explain what they had seen. The second part was a series of specific questions about the film. All participants were asked the question 'how fast were the cars going when they ___ each other? The blanks were filled with either hit, smashed, collided, bumped or contacted.
         • Results: Those with the word smashed estimates 40.5 mph, whereas those with contacted estimated 31.8 mph.
       • .Experiment 2: They used 150 students, who watched a film of a car with multiple traffic accidents. The students were questioned after the film asking 'how fast were the cars going when they smashed/hit into each other?'. One week later, the students were asked 'did you see any broken glass?'. Those who had the verb smashed answered 'yes' more than those with the word hit'. This shows that leading questions altered the memory a participant had for the event.
     • Post-Event Discussion: When co-witnesses to a crime discuss it with one another, their eyewitness testimonies may become contaminated -> combine information from other witnesses with their own memories.
       • Gabbert: Studied p's in pairs. They each watched a video of the same crime, but filmed from different points of view. They found that 71% recalled aspects they did not see in the video, but in the discussion instead. In the control group where there was no discussion, there was 0%. It was concluded that witnesses to along with each other to win social approval because they believe other witnesses are right.
         • Evaluation
           • + Tested two different populations, university students and older adults and found little difference between these two conditions. Therefore her results provide good population validity and allow us to conclude that post-even discussion affects younger and older adults in a similar way.
           • Provide an insight into the effect of post-event discussion on the accuracy of eyewitness testimony, we are unable to conclude why the distortion occurs. The distortion could be the result of poor memory, where people assimilate new information into their own accounts of the event and are unable to distinguish between what they have seen and what they have heard. On the other hand, it could be that the distortion occurs due to conformity and the social pressure from the co-witness. Further research is required answer this question.
           • Questionable ecological validity. The participants in the co-witness condition witnessed different perspectives of the same crime, as would typically be the case in real life crimes. However, like Loftus and Palmer, these witnesses knew they were taking part in an experiment and were more likely to have paid close attention to the details of the video clip.
     • Anastasi and Rhodes: Used individuals from three age groups who had to rate 24 individuals (from different age groups) for attractiveness. They found that young p's have the best memory so they can remember the most and remembered the majority in their won age group.
     • Yullie and Cutshall: Interviewed 13 people who had witnessed an armed robbery in Canada four months after. They used two misleading questions and found that the p's were not led by the leading questions, and the accounts given were very similar to their initial witness statements. It suggests Loftus and Palmers findings only apply in a laboratory setting.
   • Factors that Influence the Accuracy of EWT - ANXIETY

7. Cognitive Interview

   • Fisher et al: Developed cognitive interviews, based on proven psychological principles concerning effective memory recall.
   • 1. Context Reinstatement: Recall the scene, the weather and what you were thinking and feelings. Recall how you felt and the context enhance recall (act as cues to remembering).
   • 2. Report Everything: Report every detail you can see, even if they seem irrelevant. Witnesses might not realise that some details might help them recall significant information.
   • 3. Recall From Changed Experience: Describe the event as it would have been seen from different viewpoints. Encourages many retrieval paths.
   • 4. Recall in Reverse Order: When events are recalled un forward order, witnesses reconstruct based on their schemas. If the order is changed, they may break down those schemas and report other things.
   • Evaluation
     • + Fisher et al. (1990) found that witnesses reported greater detail in their accounts of crimes when American detectives had been trained to use the technique. - The technique is more structured than the standard technique, and it seems appropriate for crime-related interviews to be very thorough in order to gather the detail required for a useful testimony.
     • - Koehnken et al. (1999) found that witnesses recalled more incorrect information when interviewed with the cognitive interview compared to the standard interview technique, perhaps because more detailed recall increases the chances of making mistakes. The interview is far more time-consuming than the standard interview.

Images and files in the map