MEMORY Flashcards
Duration
The amount of time the information stays in the memory store for
Capacity
How much can be stored
Encoding
How the information is processed
Short term memory
- Acoustic coding
Capacity of short term memory
- One of the earliest systematic attempts to measure the capacity of short term memory was carried out by Jacobs. He devised a method called the digit span technique. The researcher gives for example 4 digits and then the participant is asked to recall these in the correct order out loud. If they get it right then they can give them 5 digits and so on until the participant can’t recall the order correctly. This determines the person’s digit span. Jacobs found that the mean span for digits was 9.3 and for letters 7.3. Miller found that generally participants can recall 7±2 chunks of information in immediate serial recall tasks.
Evaluation of capacity on STM
- One issue with Jacob’s study is that it was conducted a long time ago. In the past research in psychology lacked adequate control. For example, participants may have been distracted during the experiment. This is an example of confounding variables which weren’t controlled. Therefore, this was a limitation of his research.
- One issue with Miller’s study is that he may have overestimated the capacity of STM. Cowan reviewed other research and concluded that the capacity of STM was only about 4 chunks. This suggests that the lower end of Miller’s estimate is more appropriate than 5 items.
Duration of short term memory
- They investigated the duration of STM with nonsense trigrams. They conducted the experiment in a lab with a sample of 24 psychology students. The students had to recall meaningless three-letter trigrams (e.g THG or XVW) at different intervals (3, 6, 9, 12, 15, 18 seconds.) To prevent rehearsal the students had to count backwards from a specific number, until they were asked to recall the letters. At 3 seconds, around 80% of the trigrams were correctly recalled, whereas at 18 seconds only 10% were correctly recalled. They concluded that STM has a limited duration of 18 seconds. Furthermore, the results show that if we are unable to rehearse information, it will not be passed to LTM, providing further support for the multi store model and the idea of discrete components.
Evaluation of duration on STM
They used a sample of 24 psychology students so they may have encountered the multi-store model of memory previously and therefore may have demonstrated demand characteristics by changing their behaviour to assist the experiment. The memory of psychology students may also be different from other people, so we are unable to generalise the results of this study to non-psychology students. It could be argued that the study has low levels of ecological validity. In this study participants were asked to recall three letter trigrams, which is unlike anything people would memorise in their everyday lives. As a result we are unable to apply these results to everyday examples of memory and are unable to conclude if the duration of short term memory may be longer for more important information e.g memorising a phone number. However, the study took place in a highly controlled lab setting so extraneous variables were controlled and the procedure is easy to replicate.
Long term memory
- Semantic coding
Coding evaluation
A limitation of the research on coding is the use of artificial stimuli. Braddeley didn’t use meaningful materials. Instead he used word lists that had no personal meaning to the participants. As a result we should be cautious of generalising such results due to the low ecological validity of the experiment. For example, when processing more meaningful information, people may use semantic coding even for STM tasks. This suggests that the findings from this study has limited application. However, Baddeley’s experiment is reliable. If he wanted to repeat it with the same participants under the same conditions using the same word lists, then he would be able to do so. This would allow him to check for consistency in his findings.
Discuss the research into the multi store model of memory
Discuss the research into the working memory model
The working memory model involves three sub-sections: the central executive (the master), the phonological loop and the visuospatial sketch pad (the slave counterparts). The central executive (CE) assigns where each information piece will be stored. The phonological loop takes in verbal and sound information. It also has sub-slave counterparts: the phonological store that holds information that has been heard and the articulatory process that holds verbal information. The visuo-spatial sketchpad holds the visual and spatial information and how the sub-slave systems: the visuo-cache, which holds visual information and the inner scribe that holds spatial and movement information.
Discuss research into the effects of misleading information on the accuracy of eyewitness testimony (16 marks)
Misleading information incorporates misleading questions and post-event discussions. Loftus and Palmer (1974) examined the effect of misleading questions by using three groups students who watched a one-minute video of a car accident. One group was asked how fast the cars were going when they smashed, another group was asked the same question but the verb ‘smashed’ was replaced with ‘hit.’ The third group was not asked any questions. A week later all the groups were asked if they saw any broken glass. The participants that were asked with the verb ‘smashed’ were much more likely to report glass than the ‘hit’ and control group. These results suggest that misleading questions can significantly effect the reliability of eyewitness testimony and make people report things that they didn’t witness. However, one limitation is that their study lacks population validity. This is because their experiment consisted of 150 american students. It is reasonable to argue that the students were less experienced drivers who may be less accurate at estimating speeds. Consequently, we are unable to generalise the results to other populations, for example older experienced drivers, who may not be affected by misleading questions in the same way. Furthermore, Loftus and Palmer’s research has questionable ecological validity. This is because the participants watched a video of the car crash from start to finish but in real life witnesses rarely witness the whole event. Therefore, their results may not reflect everyday car accidents, and we are unable to conclude if the effect of leading questions is the same outside the laboratory.
Another researcher investigated the effect of post-event discussion. Her participants watched a video of a girl stealing money. However, participants in the co-witness group were told that they had watched the same video when they had in fact, seen different perspectives. 60% said that the girl was guilty despite not having seen the crime. These results highlight the issue of post-event discussion and the powerful effect that this can have on the accuracy of eyewitness testimony. This distortion could be due to conformity and the social pressure from the co-witness. Therefore, further research is required in the real world to demonstrate the exact effect of misleading information on the accuracy of eyewitness testimony.
Describe and evaluate how retrieval failure due to the absence of cues leads to forgetting
Researchers proposed that the encoding specificity principle argues that memory is most effective when information that was present at the time of coding is also present at time of retrieval. They suggested that environmental and mental cues aid recall. Consequently, there are two types of retrieval failure due to the absence of cues: context-dependent failure and state-dependent failure. Context-dependent failure occurs when environmental cues are missing and state-dependent failure occurs when an individual’s emotional state is different.
Baddeley investigated the effect of contextual cues on recall using a sample of 18 participants from a university diving club. They were divided into four conditions: learning words on land and recalling on land, learning words on land and recalling underwater, learning words underwater and, recalling underwater and learning underwater and recalling on land. It was found that words learned underwater were better recalled on land. These results provide clear support for the idea of context-dependent retrieval failure and the idea that context can aid recall. However, they used a repeated measure design so each diver took part in all four conditions. So, the participants may have experienced practice effects where their recall improved due to completing the task multiple times or fatigue effects due to boredom or tiredness from repeating the same task. So this means that the results lack validity and may not be accurate and generalisable to the target population.
Other researchers have sought to examine the effect of state-dependent retrieval failure, which occurs when an emotional state
