Multistore model

• The multi store model Suggests that memory is composed of 3 sub stores, the sensory register, short term memory and the long term memory
• Firstly information from stimuli in our environment enters the brain via the senses, most of this information is then lost almost instantly via the process of spontaneous decay
• However, if the person pays attention to something then that information can move into the short term memory, where unless it is rehearsed it is forgotten.
• If it is rehearsed enough then the information can enter the long term memory where it can be recalled from, back into the STM for recall of the information.
• Evidence to support the MSM comes from brain damage patients who have damaged one store without damaging the other
• . E.g the case study of KF who after an injury had lost the ability to recall recent information but still had an intact ability to remember older memories like his first day at school.
• The case study of KF suggest that KF had damaged his STM but not damaged his LTM, thus supporting the Multi store models theory of memory being composed of different sub stores located differently within the brain
• MSM has been criticised for being oversimplified in comparison to other models of memory. This is because the MSM suggests that short term memory is only one single store, whereas the working memory model suggests that the short term memory alone is composed of multiple sub stores.
• In the working memory model- These sub stores include the visuo-spatial sketchpad, responsible for processing visual and spatial information
• In the working memory model- phonological loop is responsible for processing auditory information and both of these “slave systems” are overseen by the central executive which temporarily stores all information before deciding which of the two slave systems is required to process the information. This may mean that the multistore model is a reductionist model of memory.
• When information from our environment enters the brain via the senses it needs to be stored for a very small amount of time until the body's processing systems can decide what to do with it
• Because there is so much information in our surroundings most of it is forgotten straight away via the process of spontaneous decay
• Unless the information is paid attention to in which case it can move into the short term memory store instead of going under the process of spontaneous decay
• Sperling investigated the capacity and duration of the sensory register by flashing a 3 by 4 grid of numbers for 50 milliseconds to the participants before asking them to recall either the top row, middle row, bottom row or all rows (indicated by a tone).
• Sperlings Results showed that when asked to recall the entire grid participants on average could only recall 4-5 numbers, however when asked to recall a specific row they could recall 3-4 numbers of any row
• Sperlings results suggest initially the whole grid was in the participants sensory register, its just forgotten so quickly that the entire grid cannot be recalled. Demonstrating that sensory register has potentially unlimited capacity, just for a very short duration
• Capacity of the STM - Jacobs Participants were presented with a string of letters or digits and had to repeat them back in the same order. The number of items increased until the participant failed to recall the sequence
• Jacob results found that the majority of participants recalled about 9 digits and about 7 letters. And the capacity increased with age during childhood.
• Based on the range of results, Jacobs concluded that STM has a limited storage capacity of 5-9 items.
• Miller also looked at the capacity of STM and suggested that it was 7 +/- 2 items. Like Jacobs he believed that the capacity of STM could be increased with ‘chunking’.
• Jacobs- was a lab experiment so was high in control of all variables, which makes it easy to replicate and check the reliability of the findings.
• Because Jacobs experiment was a lab experiment- because the setting is artificial results may lack ecological validity i.e results may not generalise to real life memory
• Duration of the STM - Peterson= Participants were shown nonsense trigrams and asked to recall them after either 3,6,9,12,15,18 seconds. During the pause they were asked to count back in 3s from a given number, this acted as an ‘interference task’ to prevent them from repeating the letters internally.
• Petersons results found that after 3 seconds, 80% of trigrams where recalled Whereas after 18 seconds only 10% of trigrams where recalled
• Petersons- results suggest that when rehearsal is prevented, very little can stay in the STM for longer than 18 seconds
• Peterson- Because this was a lab experiment it was high in control of all variables, which makes it easy to replicate and check the reliability of the findings.
• Peterson- However, because the setting is artificial results (lab) may lack ecological validity i.e results may not generalise to real life memory.
• Bahrick investigated the duration of LTM in several studies using a field study method in which participants of various ages were asked to identify people from their high school yearbook
• Bahrick- The participants were tested on their ability to match photographs to a list of names of their old classmates.
• Bahrick results- Participants that had left school 14 years ago could accurately recall their classmates 90% of the time. This then dropped to 60% after 47 years of leaving highschool
• Bahrick- results suggest that the long term memory could have a potentially unlimited duration, especially when presented with a cue to help prompt the memory.