The capacity of the short term memory (the amount of information that can be held) is 7+/- 2. It has a limited capacity and we can only hold a small amount of information before it is forgotten, although capacity is increased through chunking where the size of the units of information in memory is increased. The evidence for this was Jacobs, who gave participants increasingly longer lists of either letters or numbers, finding capacity for numbers was nine items and for letters was seven items.
The duration of the short term memory (how long the information lasts) is usually only about 18 seconds, rehearsing will make the memory last longer. Peterson and Peterson investigated in a study of giving participants trigrams to remember and then count back letters in threes (preventing rehearsal) and memory only lasted 18 seconds, as rehearsal retains material within the short term memory loop, until eventually it becomes a permanent feature of the long term memory.
The studies that were carried out for the short term memory were all carried out in a lab, to ensure control over extraneous variables and so the findings don’t really apply in an outside setting, also most memory experiments were carried out on students, and is difficult to suggest that all people will use memory in a similar way.
The long term memory involves the storage of information over extended periods of time, potentially a whole lifetime. Forgetting from long term memory may not occur due to loss of information, but rather to problems in retrieving memory traces. Storage of information longer than 30seconds counts as long term memory.
Long term memoy uses semantic encoding to take in information using verbal material, although acoustic codes may be used. Baddeley also conducted a study for encoding of the long term memory and used the same procedure as in his short term memory study, but with 20minute intervals before recall, during which participants conducted another task. The participants only had 55% recall and appears that there is semantic confusion in the long term memory.
The long term memory’s capacity is unlimited, as no one has ever shown that their brain is full although information may be lost due to decay and interface, but such losses do not occur to limitation of capacity. Linton spent 6 years creating a diary of 5,000 personal events and tested herself for recognition of events each month and found she had excellent recall of dates demonstrating the potential capacity of the long term memory.
Long term memory’s duration is potentially a lifetime, older people often have very clear childhood memories. Items in the long term memory have a longer duration if originally well learned and certain forms of information have a longer duration like information based on skills rather than just facts.
The three areas of the long term memory show that it is difficult to see how smells and tastes could be encoded semantically and reason suggests that songs must be encoded acoustically, supporting the idea of several forms of encoding in the long term memory. Also diary studies which are used in capacity studies are a type of case study and therefore are not representative of the general population.
There is strong evidence to support the components of the multi-store model and it provides an account of memory in terms of both structure and process. The structures are the three stores and the processes are attentio0n and verbal rehearsal. However it is reductionist (oversimplifies memory structures and processes). And has been criticised for focusing too much on structure and too little on process.
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waterwater1 (student)
