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02-01-2006, 03:27 AM

Theories of Memory

There are three theories:

1. The Multistore model (Atkinson –Shiffrin) which suggests there are two memory systems Short-term memory (STM) for events occurring in the immediate past (30 seconds or so) and Long-term memory (LTM) for the rest of our past.
STM has a limited capacity and is thought to code information on the basis of sounds. LTM is extensive and codes information by meaning.
Information in the Short-term memory is transferred to the Long-term memory for more permanent storage using rehearsal.
STM’s capacity has been described as “the magical number 7 plus or minus 2”(Miller). This can be increased by chunking. Chunking also gives meaning to the information which means that it will be more likely to be remembered.
Support for this theory comes from experiments on the primacy-recency effect and on rehearsal:
Murdock found that the participants recalled items from the end and the beginning of lists and forgot those from the middle. The idea here is that the words at the end (recency) are being retrieved from the STM and those from the beginning (primacy) from LTM.
Peterson et al gave participants short series of letters (CPQ etc) and then asked them to count backwards in threes. This interfered with rehearsal and resulted in most of the material being forgotten. It seems that rehearsal is needed to retain information in the STM and also transfer it to LTM.
The problems with this theory are that other studies show that rehearsal doesn’t always improve memory and also it is questionable whether memory is really divided into compartments.

2. Craik and Lockhart’s levels of processing model. This states that how well we remember information depends on how well we have ‘processed’ it.
Rehearsal does not necessarily result in better memory but giving meaning to words deepened the processing and results in better recall. This is known as ‘elaboration rehearsal’. (see also mnemonics below) Maintenance rehearsal is where words are only processed at a superficial, shallow level. Craik and Lockhart gave participants lists of words with questions about each word, e.g. is the word in capitals (shallow, visual processing); does the word rhyme with…(moderate, phonetic processing); fit the word into a sentence (deep, meaningful processing). Participants remembered more words from the third group (deeper processing). It has also been found that there was no difference whether or no the participants were expecting a memory test.
This theory does take into account how well the item is learnt in the first place and is supported by evidence from the work of Bartlett and others. However, it is hard to define ‘depth’ of processing and other researchers have found that maintenance rehearsal can also improve memory.

3. Constructive memory - Bartlett examined memory in a more realistic way by
asking participants to repeat a story he told them called ‘The War of the Ghosts’ to other people. This story is about a battle between two Indian tribes, one side of which is made up of ghosts. Bartlett found that participants altered some parts of the story to fit in with their own beliefs and ideas. He called this “effort after meaning”. This shows that memory is an active process which involves the reconstruction of events and can be affected also by feelings.
This theory does allow us to relate memory to everyday life but the story used is ambiguous and not like our usual experience.

Applications of memory research and ways to improve memory
All these theories of memory نقرتين لعرض الصورة في صفحة مستقلة

l us how to improve our memories in different ways. The Atkinson – Shiffrin model would suggest that rehearsal (i.e. revision) helps us to remember things better. The Levels of Processing model suggests on the other hand that giving information meaning (i.e. understanding what you are trying to learn) will help us to remember it.
Mnemonics are another way of improving memory. A mnemonic is an aid to memory. We can help store and recall information using visual and verbal systems, for example one visual mnemonics is the method of loci – we imagine going on a familiar walk and place the items to be remembered along the way e.g. potatoes in the tree. It is important to visualise bizarre images. When you need to remember the information then you visualise/imagine going on the walk again and seeing the items as you go. Examples of verbal mnemonics are rhymes (e.g. 30 days hath September…) or making a set of words from the first letter of words to be remembered e.g. Richard Of York Gave Battle In Vain (ROYGBIV – order of the colours of the rainbow – red, orange, yellow, green, blue, indigo, violet).