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.
